<%BANNER%>

Residual Herbicide Impact on Native Plant Restoration as an Integrated Approach to Cogongrass Management


PAGE 1

RESIDUAL HERBICIDE IMPACT ON NA TIVE PLANT RESTORATION AS AN INTEGRATED APPROACH TO COGONGRASS MANAGEMENT By MELISSA CAROLE BARRON A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLOR IDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2005

PAGE 2

Copyright 2005 by Melissa Carole Barron

PAGE 3

ACKNOWLEDGMENTS First and foremost, I would like to thank God for the strength and guidance He has constantly provided for me. My parents, Bryant and Carol Barron, have been my biggest fans throughout every moment of my life. I am grateful to my mother for her endless love and encouragement. She has been and always will be the person I most aspire to become. I thank my father for being such a supportive and loving dad and close friend. He always lifts my spirits with a good laugh and kind words from his heart. I thank my close friends Ron Emerson and Casey Jones for their love and encouragement which have given me the confidence I need to get through the tough times. Thanks go to my running friends, Tim Vinson, Debbie McCarthy, Elizabeth Nelson, and Beth Martin, for motivating me in all aspects of life. Endless appreciation is given to my major advisor, Dr. Greg MacDonald, for his constant faith in my abilities to perform well in this graduate program. Having his vote of confidence taught me to have a stronger believe in myself. Thanks go to Bob Querns for similarly providing advice and good conversation throughout my time in this program. Finally, I thank Nick Pool for being my best friend and top supporter throughout our time in graduate school. Our friendship extends from fieldwork to free time, and this entire experience would not have been complete without him. iii

PAGE 4

TABLE OF CONTENTS page ACKNOWLEDGMENTS.................................................................................................iii LIST OF TABLES.............................................................................................................vi LIST OF FIGURES.........................................................................................................viii ABSTRACT......................................................................................................................xii CHAPTER 1 INTRODUCTION........................................................................................................1 Cogongrass Characteristics...........................................................................................1 Current Management Strategies...................................................................................3 Revegetation.................................................................................................................8 2 THE RESPONSE OF SELECTED REVEGETATION SPECIES TO IMAZAPYR CONCENTRATIONS IN SOIL...........................................................12 Introduction.................................................................................................................12 Materials and Methods...............................................................................................15 Results and Discussion...............................................................................................16 3 IMAZAPYR RESIDUAL MEASUREMENTS USING CORN ROOT BIOASSAY................................................................................................................47 Introduction.................................................................................................................47 Materials and Methods...............................................................................................51 Results and Discussion...............................................................................................53 4 NATURAL RECRUITMENT OF PLANT SPECIES IN AREAS PREVIOUSLY INFESTED WITH COGONGRASS..........................................................................62 Introduction.................................................................................................................62 Materials and Methods...............................................................................................65 Long Term Cogongrass Control..........................................................................66 Rhizome Distribution..........................................................................................66 Native Species Recolonization............................................................................66 iv

PAGE 5

Results and Discussion...............................................................................................67 Long Term Cogongrass Control..........................................................................67 Rhizome Distribution..........................................................................................68 Native Species Recolonization............................................................................68 5 CONCLUSIONS........................................................................................................75 APPENDIX STANDARD CURVES FOR CORN ROOT BIOASSAY...............................................80 LIST OF REFERENCES...................................................................................................91 BIOGRAPHICAL SKETCH.............................................................................................95 v

PAGE 6

LIST OF TABLES Table page 2.1 Species used in revegetation study in Citra, Florida................................................42 2.3 The effect of imazapyr soil concentration on percent mortality of selected revegetation species 10 weeks after planting Experiment 2 initiated on July 21, 2004, in Citra, FL P60 values reflect the predicted imazapyr concentration that would result in less than 60% mortality...................................................................44 2.4 The effect of imazapyr soil concentration on percent injury of selected revegetation species 10 weeks after planting Experiment 1 initiated on June 22, 2004, in Citra, FL I30 values reflect the highest predicted imazapyr concentration that would cause no greater than 30% injury....................................45 2.5 The effect of imazapyr soil concentration on percent injury of selected revegetation species 10 weeks after planting Experiment 2 initiated on July 21, 2004, in Citra, FL I30 values reflect the highest predicted imazapyr concentration that would cause no greater than 30% injury....................................46 3.1 The predicted concentration values of imazapyr using a corn root bioassay from sand tailings soil in Polk County..............................................................................58 3.2 The predicted concentration values of imazapyr using a corn root bioassay from clay soil in Polk County...........................................................................................58 3.3 The predicted concentration values of imazapyr using a corn root bioassay from overburden soil in Polk County................................................................................59 3.4 Estimated revegetation timeframe as related to plant species and soil type according to Experiment 1.......................................................................................60 3.5 Estimated revegetation timeframe as related to plant species and soil type according to Experiment 2.......................................................................................61 4.1 Cogongrass control over a 4-year period Visual ratings taken in January 2004 in Polk County..........................................................................................................71 4.2 The effect of glyphosate and imazapyr on native species 39 months after application in Polk County (area sprayed in Fall 2000)...........................................71 vi

PAGE 7

4.3 Category 1 soil samplesno cogongrass within 0.6 meters of core samples Rhizome data taken 39 months after herbicide application in Polk County............71 4.4 Category 2 soil samplescogongrass within 0.6 meters of core samples Rhizome data taken 39 months after herbicide application in Polk County............72 4.5 Category 3 soil samplescogongrass present within core samples Rhizome data taken 39 months after herbicide application in Polk County...................................72 4.6 Natural presence of species on sand soil type burned and treated with imazapyr (Arsenal) in the fall of 2002 at Tenoroc WMA Visual evaluations of percent cover were taken in fall of 2004 (24 months after treatment)..................................73 4.7 Natural presence of species on overburden soil type burned and treated with imazapyr (Arsenal) in the fall of 2002 at Tenoroc WMA Visual evaluations of percent cover were taken in fall of 2004 (24 months after treatment).................74 vii

PAGE 8

LIST OF FIGURES Figure page 2.1 Andropogon virginicus (broomsedge) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1 Means of 4 replications present with standard error........................21 2.2 Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application Experiment initiated on June 22, 2004, in Citra, Florida Means of 12 replications present with standard error...................................................................22 2.3 Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1 Means of 4 replications present with standard error........................23 2.4 Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1 Means of 4 replications present with standard error........................24 2.5 Eucalyptus amplifolia response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1 Means of 4 replications present with standard error................................................25 2.6 Eucalyptus grandis response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1 Means of 4 replications present with standard error............................................................26 2.7 Panicum virgatum (switchgrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1 Means of 4 replications present with standard error........................27 2.8 Andropogon virginicus (broomsedge) response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error........................28 2.9 Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error................................................29 viii

PAGE 9

2.10 Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error........................30 2.11 Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error........................31 2.12 Eucalyptus amplifolia response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error............................................................32 2.13 Eucalyptus grandis response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error............................................................33 2.14 Panicum virgatum (switchgrass) response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error........................34 2.15 Andropogon virginicus (broomsedge) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error........................35 2.16 Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error........................36 2.17 Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error........................37 2.18 Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error........................38 2.19 Eucalyptus amplifolia response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error................................................39 2.20 Eucalyptus grandis response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error............................................................40 2.21 Panicum virgatum (switchgrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2 Means of 4 replications present with standard error........................41 ix

PAGE 10

A-1 The effect of imazapyr concentration on corn root length in a sand tailings soil type in Polk County, FL Regression analysis used to determine unknown imazapyr concentrations in sand tailings soil 0 Months After Treatment (MAT) Values shown in Table 3.1.......................................................................................80 A-2 The effect of imazapyr concentration on corn root length in a sand tailings soil type in Polk County, FL Regression analysis used to determine unknown imazapyr concentrations in sand tailings soil 1 Month After Treatment (MAT) Values shown in Table 3.1.......................................................................................81 A-3 The effect of imazapyr concentration on corn root length in a sand tailings soil type in Polk County, FL Regression analysis used to determine unknown imazapyr concentrations in sand tailings soil 3 Months After Treatment (MAT) Values shown in Table 3.1.......................................................................................82 A-4 The effect of imazapyr concentration on corn root length in a clay soil type in Polk County, FL Regression analysis used to determine unknown imazapyr concentrations in clay soil 0 Months After Treatment (MAT) Values shown in Table 3.2...................................................................................................................83 A-5 The effect of imazapyr concentration on corn root length in a clay soil type in Polk County, FL Regression analysis used to determine unknown imazapyr concentrations in clay soil 1 Month After Treatment (MAT) Values shown in Table 3.2...................................................................................................................84 A-6 The effect of imazapyr concentration on corn root length in a clay soil type in Polk County, FL Regression analysis used to determine unknown imazapyr concentrations in clay soil 3 Months After Treatment (MAT) Values shown in Table 3.2...................................................................................................................85 A-7 The effect of imazapyr concentration on corn root length in an overburden soil type in Polk County, FL Regression analysis used to determine unknown imazapyr concentrations in overburden soil 0 Months After Treatment (MAT) Values shown in Table 3.3.......................................................................................86 A-8 The effect of imazapyr concentration on corn root length in an overburden soil type in Polk County, FL Regression analysis used to determine unknown imazapyr concentrations in overburden soil 1 Month After Treatment (MAT) Values shown in Table 3.3.......................................................................................87 A-9 The effect of imazapyr concentration on corn root length in an overburden soil type in Polk County, FL Regression analysis used to determine unknown imazapyr concentrations in overburden soil 3 Months After Treatment (MAT) Values shown in Table 3.3.......................................................................................88 x

PAGE 11

A-10 Imazapyr concentration as a function of days after treatment (DAT) in a clay soil type in Polk County, FL Regression analysis used to determine imazapyr concentrations over time after initial application of 0.84 kg ai/ha Values shown in Table 3.4...............................................................................................................89 A-11 Imazapyr concentration as a function of days after treatment (DAT) in an overburden soil type in Polk County, FL Regression analysis used to determine imazapyr concentrations over time after initial application of 0.84 kg ai/ha Values shown in Table 3.5.......................................................................................90 xi

PAGE 12

Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science RESIDUAL HERBICIDE IMPACT ON NATIVE PLANT RESTORATION AS AN INTEGRATED APPROACH TO COGONGRASS MANAGEMENT By Melissa Carole Barron August 2005 Chair: Greg E. MacDonald Major Department: Agronomy Field studies were conducted to evaluate the impact of soil residues of imazapyr on native species establishment. Both broomsedge and silkgrass showed at least 30% injury at all rates of imazapyr, and only Eucalyptus grandis showed less than 30% injury at rates above 0.033 kg ai/ha. Imazapyr caused significant injury to all species at rates higher than 0.56 kg ai/ha. Wax myrtle and longleaf pine showed greater than 60% mortality at the lowest rate of imazapyr (0.018 kg ai/ha), while mimosa and both Eucalyptus species show less than 60% mortality at the highest rate of 1.12 kg ai/ha. Three areas were sprayed with 0.84, 1.68, and 3.36 kg ai/ha imazapyr in 2002 and soil core sampling occurred immediately prior to application, immediately after application, and at 1, 3, 6, and 12 months after treatment (MAT). Imazapyr concentration was determined using a corn-root bioassay. At the lowest application rate of 0.84 kg ai/ha, sand soil samples give a consistently similar rate at 0 MAT. There was no detection of imazapyr at 1 MAT, and a trace amount was detected at 3 MAT (0.0005 kg xii

PAGE 13

ai/ha). In the clay soil, samples taken 0 MAT were similar in value (0.078, 0.066, and 0.074 kg ai/ha for the plots sprayed with 0.84, 1.68, and 3.36 kg ai/ha, respectively). In the overburden area, the plots treated with 0.84 kg ai/ha had measured residues that decreased to 0.016 kg ai/ha 1 MAT and 0.0095 kg ai/ha 3 MAT. Overall, imazapyr dissipation was faster in sand tailings, with mixed results occurring between clay and overburden soil. In the area treated in 2000, 25 random soil samples were taken from each plot and categorized based on proximity to cogongrass. Approximately half of all samples were in a cogongrass-free area for both glyphosate and imazapyr plots. Thirty-eight percent of samples taken were within 2 feet of cogongrass and approximately half of these samples contained rhizomes. Only 9 and 6% of samples from the glyphosate and imazapyr plots were within cogongrass patch and all these samples contained rhizomes. Bioassay data were combined with plant species injury and mortality data to create a timetable to best estimate optimal planting dates per species. In both the clay and overburden area, six species can be planted immediately after imazapyr application and expect to show at least a 40% survival rate. E. grandis can be planted after one month in clay and overburden to exhibit no more than 30% injury 10 weeks after planting (WAP). E. amplifolia, mimosa, and bluejack oak also show slightly longer time periods in overburden soils as compared to clay soils. Silkgrass and broomsedge need three months before planting until soil residues are within range of I30 values. Wiregrass was the most sensitive showing at least 30% injury at all rates of imazapyr regardless of plantback interval. In a repeated study, similar predicted dates were generated according to I30 values for E. grandis and switchgrass. xiii

PAGE 14

CHAPTER 1 INTRODUCTION Cogongrass [Imperata cylindrica (L.) Beauv.] is a rhizomatous perennial grass species found throughout much of the tropical and sub-tropical regions of the world, being widely distributed in Africa, Asia, Europe, North and South America, and Australia (Holm et al. 1977). This species predominates in the eastern hemisphere, where it covers over 200 million hectares in Asia alone (Garrity et al. 1996). Worldwide, cogongrass infests over 500 million hectares and is considered the worlds seventh worst weed (Holm et al. 1977). In the United States, it is widely spread throughout Florida and much of southern Alabama and Mississippi, infesting several hundred thousand acres (Johnson et al. 1999). Cogongrass can usually be found in predominately non-agricultural settings in the United States, and spreads over vast areas where vegetation is marginally supported, suppressing and displacing many native plants (Bryson and Carter 1993). Cogongrass Characteristics First introduced into the U.S. as a packing material from Japan in 1912, cogongrass initially invaded areas of Alabama (Dickens 1974). The weed was later introduced purposefully in Mississippi as potential forage in 1921 (Patterson et al. 1979). Other forage evaluations of cogongrass were later carried out in Texas, Alabama, Mississippi, and Florida with spread being hindered from the Texas site due to winter kill (Dickens and Moore 1974). Studies concluded that this potential forage was not suitable for livestock because of its high silica content in the leaf tissue. This highly aggressive weed is now a primary invader of disturbed lands, displacing desirable and native vegetation 1

PAGE 15

2 (Terry et al. 1997). Unfortunately, the occurrence of cogongrass has increased drastically during the past twenty years (Bryson and Carter 1993) and is currently reported in much of the southeast United States. Cogongrass tolerates a wide range of soil conditions but appears to grow best in soils with acidic pH, low fertility, and low organic matter. Cogongrass infestations occur in a wide range of habitats from shoreline course sands to the >80% clay soils of reclaimed phosphate settling ponds (MacDonald 2004). Cogongrass is highly efficient in nutrient uptake (Saxena and Ramakrishnan 1983) and reportedly has an association with mycorrhiza, which may help explain its competitiveness in unfertile soils (Brook 1989). Cogongrass is able to spread and persist through several survival strategies including an extensive rhizome system, adaptation to poor soils, drought tolerance, prolific wind disseminated seed production, fire adaptability, and high genetic plasticity (Holm et al. 1977; Dozier et al. 1998). With the exception of a flowering stalk, cogongrass is virtually stemless. The leaves are slender, flat, and linear-lanceolate, and possess serrated margins and a prominent off-center white mid-rib (Terry et al. 1997). Silicates accumulate in the serrated margins of the leaves, which deter herbivory (Dozier et al. 1998). Cogongrass rhizomes can comprise over 60% of the total plant biomass (Sajise 1976). This low shoot to root/rhizome ratio contributes to its rapid regrowth after cutting or burning. Cogongrass rhizomes are white and tough with shortened internodes. Specialized anatomical features help to conserve water within the central cylinder and help to resist breakage and disruption when trampling or disturbance occurs (Holm et al. 1977). Rhizomes are predominately found within the top 15 cm of fine textured soils or the top 40 cm of course textured soils. However, rhizomes have been discovered

PAGE 16

3 growing at depths of 120 cm (Holm et al. 1977; Gaffney 1996). According to Tominaga (2003), cogongrass rhizomes can be grouped in the following three categories: tillering, secondary colonizing, and pioneer rhizomes. Unlike cogongrass seedlings, which are defined as R-strategist (ruderal) and invade open patches in disturbed habitats, rhizomes from current cogongrass stands are defined as C-strategist (competitor) that can persist in established populations (Tominaga 2003). These rhizomes provide a tremendous amount of biomass for regeneration after foliar loss, with one study showing rhizome length of over 89 meters within one square meter of soil surface area (Lee 1977). Cogongrass is also a prolific seed producer, with shortly branched, compacted and dense seed heads producing over 3000 seeds per plant. Each brownish colored seed (grain) possesses a plume of long hairs that affect wind dispersal. These plumed seeds travel over long distances averaging 15 meters (Holm et al. 1977), but Hubbard (1944) stated that cogongrass seeds could travel up to 24 kilometers over open country. Flowering is highly variable depending on region and environment. Cogongrass flowering occurs year-round in the Philippines (Holm et al. 1977), whereas flowering in the United States occurs in the late winter/early spring (Shilling et al. 1997). Disturbances including burning, mowing, grazing, frost, or the addition of nitrogen can also stimulate flowering (Holm et al. 1977; Soerjani 1970; Sajise 1972). Current Management Strategies Current control methods for cogongrass rely heavily on chemical treatments, which provide limited long-term control. The main reason for this limited control is the presence of cogongrass rhizomes, which can comprise over 2/3 the total plant biomass. These rhizomes contain multiple nodes from which regrowth may occur, but generally only a fraction sprout at any given time (English 1998). Mowing is also often included as

PAGE 17

4 a control method with chemical application. While mowing alone does not effectively control cogongrass, it has been shown to reduce rhizome and foliar biomass (Willard and Shilling 1990). However, the integration of mowing with chemical applications resulted in poor control compared to conventional application techniques (Marchbanks et al. 2002). Cultivation has proven effective, with little or no regrowth occurring under continuously cultivated conditions (Hartley 1949). However, the high costs and limited utility in many areas precludes use of this type of method. Johnson et al. (1999) showed that a single discing in combination with herbicides did not significantly enhance cogongrass control compared to herbicide alone. A second discing provided better control than just single discing but also did not enhance control over herbicide treatments. Therefore, sporadic mechanical control treatments are less effective than other approaches and often exacerbate the situation. Over the last three decades, several herbicides have been evaluated for cogongrass control with minimal success (Dickens and Buchanan 1975). Presently, the most effective herbicides are glyphosate [N-(phosphonomethyl)glycine] and imazapyr {()-2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imadazol-2-yl]-3-pyridinecarboxylic acid (Dozier et al. 1998). Generally, imazapyr provides control for a longer period of time due to soil activity, but off-target effects limits use in certain areas (MacDonald et al. 2002). These chemicals are broad-spectrum, systemic herbicides that, in general, can effectively control cogongrass for one year after application (Miller, 2000). Imazapyr is used to control annual and perennial weeds, deciduous trees, and vines in rights-of-way and other noncropland areas, as well as in forestry as a conifer releasing agent (Anon. 2002). The mode of action of imazapyr, a member of the imidazolinone family of

PAGE 18

5 herbicides, involves the inhibition of acetohydroxyacid synthase (AHAS), which is needed for branched chain amino acid synthesis (Shaner 1991). Field half-life values range from 25-142 days depending on soil type and environmental conditions, with soil adsorption increasing as organic matter and clay content increase (Anon. 2002). Imazapyr is relatively harmless to animals, and if used correctly, has minimal off-target impacts (Mangels 1991). Research to date has indicated imazapyr at 1.12 kg ai/ha applied late summer/early fall provides cogongrass control for as long as 18 months (Dozier et al. 1998). This application timing has been attributed to the basipetal flow of photosynthates and herbicides that occur at this time of year, which results in improved rhizome lethality (Gaffney 1996). After this time, cogongrass will re-form a monotypic stand within 1-2 years if additional treatments are not imposed (Dozier et al. 1998). Burning prior to herbicide application has shown the ability to remove old growth and dead biomass and provides several benefits (Johnson et al. 1999). Starch storage reserves in rhizomes are forced to re-allocate to produce new shoot growth, thereby weakening the rhizomes. Also, removal of the substantial biomass improves the ability to effectively apply herbicides. Herbicide application to the regrowth of new plant tissues also maximizes absorption and results in greater efficacy (Johnson et al. 1999). Imazapyr provides good control of cogongrass but has limited utility due to the long residual effects of this compound, which could hinder revegetation strategies and native recruitment. In previous research, several native species were evaluated under greenhouse conditions for response to imazapyr used in non-cropland situations. Imazapyr caused severe injury to most species evaluated, but injury was restricted to a foliar application only (Miller et al. 2002). A more accurate assessment of successful

PAGE 19

6 native species growth and establishment is when the concentration of residual herbicide in the soil is at a tolerable level. Initial research indicates the residual activity of imazapyr may be less than theorized, allowing for more flexibility in a revegetation scheme. A better understanding of native species response to imazapyr soil concentration could provide greater flexibility when developing revegetation schemes. Varying initial rate and time of transplanting after application could provide land managers with a greater number of native species to select. Other major factors in the determination of timing and revegetation include the total amount of chemical used and the soil type to which the herbicide is applied. Soil type has an important influence on the residual amount of herbicide due to the soil structure and content of clay and organic matter. In sandy soils, there are fewer charged sites that the herbicide can adsorb to, and leaching often occurs. Therefore, sandy soils contain less residual matter after a given period of time than a clay soil, which has a much greater affinity for adsorption (McBride, 1994). Also, herbicides tend to persist longer in loamy and silty soils due to reduced leaching compared to sandy soils. Because of the diversity of soils in Florida, as well as much of the U.S., an understanding of herbicide persistence as a function of soil type is important in predicting the best time to revegetate. In central Florida, reclaimed mining sites have a diverse collection of soil types with overburden, sand tailings and phosphatic clay pits being three of the most prominent (Richardson et al. 2003). Overburden, a mixture of sand and clay, is removed from the land surface above the ore body and piled on the side. Overburden shows the highest variability in soil texture, soil color and soil chemical parameters (Segal et al. 2001).

PAGE 20

7 This soil type is on average composed of 80% sand, 8% silt, and 12% clay with a pH of 5.8.1 Overburden has slightly greater clay and silt content, higher water-holding capacity, and greater P and K content than native Floridian soils, which may give aggressive weeds a competitive advantage over slower-growing natives (Richardson et al. 2003). The phosphate ore currently being mined is an unconsolidated mixture of sand, clay, and phosphate mineral. The sand tailings are separated from this ore and hydraulically pumped to fill mine cuts between overburden piles. Although sand tailings are usually nutrient-poor and droughty compared with these three other soil types (Segal et al. 2001), they have higher P and K contents and slightly coarser grain sizes than native soils (Kluson et al. 2000). Phosphatic clay is washed from phosphate ore and pumped, at about 3-5% solids, to settling areas. This clay commonly has pH values near 7.5, while some older sites with good forest cover and higher organic matter have pH values near 6.8. This soil type covers about 40% of the mined area and is considered highly fertile (Stricker 2000). These three soil types involved in phosphate mining processes are highly diverse in nature, yet they are all susceptible to cogongrass and other non-native weed invasions. This is due to the disturbance of the areas during the mining process and the associated harsh conditions to which plants are subjected. For long-term control of cogongrass, further methods need to be integrated into the traditional control techniques mentioned above. Even in areas where management has been successful, cogongrass re-infestation will often occur. Because of this, studying the 1 Richardson, S.G. 2004. Personal Communication.

PAGE 21

8 reinfestation aspects of cogongrass, especially from rhizomes, is also an important aspect of overall integrated control. Revegetation In Florida, reclaimed phosphate mining areas are important areas for cogongrass control and native plant restoration. Because mining disturbance creates a hospitable environment for weed invasion, one of the most difficult barriers to successful restoration is the control of cogongrass and other invasive weeds. Effectively returning mined lands and lands infested with cogongrass to self-sustaining native upland communities with functional ecological value would be beneficial to the mining industry, local communities, and the state of Florida (Miller et al. 2002). Mined land restoration is crucial in Florida because upland ecosystems in Florida have been dramatically reduced in area (Richardson et al. 2003) due to a variety of causes, including mining, development, and agriculture. Determining which species will be most successful in a restoration scheme involves several factors, such as imazapyr tolerance, competitiveness with cogongrass and other invasive species, and overall desirability. The cornerstone of integrated management and restoration is the establishment of a self-sustaining native plant community. Previous studies show that wiregrass (Aristida beyrichiana Trin. and Rupr.) is a pivotal native grass in areas of phosphate mining and is highly desired for use in reclamation (Norcini et al. 2003). Wiregrass is often the dominant grass species in Florida uplands, and foresters have long preferred this species as well as broomsedge (Andropogon virginicus L.) for pine forest understory because of their ability to carry a fire (Pfaff et al. 2002). Silkgrass [Pityopsis graminifolia (Michx.) Nutt.] also proved highly adaptable to reclaimed mining land soils and was selected as a candidate for future large-scale assembly and seed source development (Pfaff et al.

PAGE 22

9 2002). Gopher apple (Licania michauxii Prance) is a drought-tolerant woody plant native to Florida uplands, is locally abundant, and can function as a ground cover. It is consistently demanded for use in a variety of restoration and mitigation projects, and it is a prime candidate for use in mine reclamation (Norcini et al. 2003). Another species of interest is lovegrass [Eragrostis spectabilis (Pursh) Steud.]. This pioneer species is important because it has the potential to be a good competitor against aggressive species while allowing other slow-growing species to become established (Segal et al, 2001). Wax myrtle [Myrica cerifera (L.) Small], switchgrass (Panicum virgatum L.), and creeping mimosa (Mimosa strigillosa Torr. and Gray) are three additional perennial species that have been studied in plantback studies involving imazapyr (Miller et al, 2002). Tree species are also important in successful native plant restoration. Weed management in pine (Pinus spp.) has been extensively studied, and imazapyr is widely used in pine culture throughout the south (Lauer et al. 2002). Longleaf pine (Pinus palustris P. Mill.) is native to Florida and is widely desired in revegetation scenarios. In addition to pines, Florida was historically heavily forested with stands of bluejack oak (Quercus incana Bartr.) and sand live oak (Quercus geminata Small). Recent studies have tested imazapyr as a site preparation herbicide for oak species with promising results (Schuler et al. 2004). Other trees for potential use in a revegetation scheme are eucalyptus (both Eucalyptus grandis W. Hill ex Maid. and Eucalyptus amplifolia Naudin). Although these eucalyptus species are considered exotic and non-native, they are shown to be non-invasive. This is because eucalyptus has been grown in south and central Florida since the 1970s with no evidence of escaping into the environment

PAGE 23

10 (Rockwood 1996). These trees are potentially good at suppressing cogongrass after initial control because of good growth during the first year while typically dominating other vegetation for the rest of the rotation (Stricker 2000). Eucalyptus also grows faster than native tree species in peninsular Florida (Rockwood et al. 1996), making them good candidates for bioenergy crop production. The humid Lower South has the most suitable climate (warm temperature, high rainfall, and longest warm growing season) for biomass crops in the continental US, and Eucalyptus species, especially Eucalyptus grandis, is now showing the greatest potential for reclaimed mining lands (Prine and French 1999). Under intensive cultivation and close spacing, E. amplifolia can yield as much as 25 dry mg/ha/yr on good sites in northeastern Florida, and E. grandis can yield up to 35 dry mg/ha/yr in central and southern Florida (Prine and French 1999; Segrest et al. 1998). This wide selection of both native and non-native plant species possesses qualities that are desirable for many revegetation studies for reclamation. Characteristics such as tolerability to variable amounts of imazapyr in the soil and effective competitiveness with cogongrass regrowth are important in choosing which plant species to use in successful revegetation work. In combination with more traditional control methods, a comprehensive revegetation plan might be the most important link in overall cogongrass control and spread prevention. If complete cogongrass control is the ultimate goal, the utilization of current management techniques has been shown to be only marginally successful. Eradication with herbicides such as imazapyr is theoretically possible but is undesirable for several reasons. This type of approach invites erosion, is unsightly, and will prevent the introduction of desirable native species. Ideally, cogongrass should be gradually

PAGE 24

11 eliminated while desirable species are introduced. Taking into consideration factors such as residual herbicide amount, plant tolerance levels, and soil types can be very beneficial to an overall cogongrass control strategy. Also, visual monitoring of both disturbed and undisturbed areas previously treated for cogongrass will provide information on plant succession, rhizome dormancy and spread, and long-term growth habits of cogongrass in competition with other, more desirable plant species.

PAGE 25

CHAPTER 2 THE RESPONSE OF SELECTED REVEGETATION SPECIES TO IMAZAPYR CONCENTRATIONS IN SOIL Introduction Cogongrass [Imperata cylindrica (L.) Beauv.] is an aggressive perennial grass species which infests over 500 million hectares worldwide and is considered the worlds seventh worst weed (Holm et al. 1977). In the United States, it is widely spread throughout Florida and much of southern Alabama and Mississippi, infesting several hundred thousand acres (Johnson et al. 1999). Cogongrass can usually be found in predominately non-agricultural settings in the United States. Cogongrass tends to spread over vast areas where vegetation is marginally supported, suppressing and displacing many native plants (Bryson and Carter 1993). Cogongrass tolerates a wide range of soil conditions but appears to grow best in soils with acidic pH, low fertility, and low organic matter. This invasive plant is able to spread and persist through several survival strategies including an extensive rhizome system, adaptation to poor soils, drought tolerance, prolific wind disseminated seed production, fire adaptability, and high genetic plasticity (Holm et al. 1977, Dozier et al. 1998). Current control methods for cogongrass rely heavily on chemical treatment, which provides limited long-term control. To date, the most effective herbicides for cogongrass management are glyphosate and imazapyr (Dozier et al. 1998; Barnett et al. 2000; MacDonald et al. 2002). Generally, imazapyr provides control for a longer period of time due to soil activity, but off-target effects limits use in certain areas (MacDonald et 12

PAGE 26

13 al. 2002). Research to date has indicated imazapyr at 1.12 kg-ai/ha applied late summer/early fall provides control for as long as 18 months (Dozier et al. 1998). Burning prior to herbicide application provides several benefits including rhizome weakening due to new shoot growth and removal of old biomass for more effective herbicide application (Johnson et al. 1999). Imazapyr provides good control of cogongrass but has limited utility in reclamation projects due to the long residual effects of this compound. Although there is ample information on the effect of several herbicides on weedy species, little information regarding the herbicide tolerance (i.e., selectivity potential) of native species is available. In previous research by Miller et al. (2002), several native species were evaluated under greenhouse conditions for response to imazapyr used in non-cropland situations. Imazapyr caused severe injury to most species, but this injury was reflective to a foliar application only. In most practical field situations, herbicides are usually sprayed to control cogongrass with little or no subsequent control measures. These areas often become reinfested because of a lack of suppressive cover and/or incomplete initial control. An important step in the further suppression of cogongrass is to establish a native plant cover as soon as the residual herbicide levels in the soil become tolerable to the revegetation species. It is important to quantify soil residual levels to best predict effective revegetation timing for the most effective suppression of cogongrass. Therefore, an understanding of plant species response to imazapyr residues in soil will ultimately be beneficial for restoration purposes in southeastern ecosystems (MacDonald et al., 2002).

PAGE 27

14 Many plants tolerate herbicides, including imazapyr, differentially, so an understanding of the effects of imazapyr on the selected revegetated species is crucial. Determining which species will be most successful in plantback situations involves several factors, such as imazapyr tolerance, competitiveness with cogongrass and other invasive species, and overall desirability. Because the cornerstone of integrated management and restoration is the establishment of a self-sustaining native plant community, primary emphasis for this study was placed on native Floridian plant species. Species such as wiregrass (Aristida beyrichiana), broomsedge (Andropogon virginicus), and silkgrass (Pityopsis graminifolia) are desired native grasses for use in reclamation (Norcini et al. 2003). Woody plants such as gopher apple (Licania michauxii), wax myrtle (Myrica cerifera), and creeping mimosa (Mimosa strigillosa) have also been studied in plantback research involving imazapyr (Miller et al, 2002). Other species of interest are lovegrass (Eragrostis spectabilis) and swichgrass (Panicum virgatum), which can potentially be good competitors against aggressive species while allowing other slow-growing species to become established (Segal et al, 2001). Tree species are also important in successful native plant restoration. Longleaf pine (Pinus palustris) is native to Florida and is widely desired in revegetation schemes. In addition, Florida was historically heavily forested with stands of bluejack oak (Quercus incana) and sand live oak (Quercus geminata). Recent studies have tested imazapyr as a site preparation herbicide for oak species with promising results (Schuler et al. 2004). Other trees for potential use in a revegetation scheme are eucalyptus (both Eucalyptus grandis and Eucalyptus amplifolia). Although these eucalyptus species are considered exotic and non-native, they are non-invasive. These trees are potentially good

PAGE 28

15 at suppressing cogongrass after initial control because they show good growth during the first year while typically dominating other vegetation for the rest of the rotation (Stricter 2000). Eucalyptus also grow faster than native tree species in peninsular Florida (Rockwood et al. 1996), making them good candidates for bioenergy crop production. This wide selection of both native and non-native plant species possesses qualities that are desirable for many revegetation scenarios. Characteristics such as tolerability to variable amounts of imazapyr in the soil and effective competitiveness with cogongrass regrowth are important in choosing which plant species to use in successful revegetation work. Materials and Methods Field experiments were conducted in the summer of 2004 at the Plant Science Research and Education Unit (PSREU) in Citra, Florida. The soil type at Citra is a Sparr sand (loamy, siliceous, hyperthermice Grossa-renic paleudult) with 1% organic matter and a pH of 6.4. The field area was conventionally prepared using standard tillage practices. Imazapyr (Arsenal 4 SC) was applied at 0.0, 0.018, 0.036, 0.071, 0.14, 0.28, 0.56, and 1.12 kg-ai/ha using a backpack CO2 sprayer calibrated to deliver 187 L/ha. Applications occurred on June 22 and July 21, 2004, for the first and second experiments, respectively. Immediately after application, the herbicide was lightly incorporated into the soil to a depth of 5 to 7.6 centimeters. Plots were 6 x 7.6 m plots and arranged in a completely randomized block design with four replications. Within 24 hours of herbicide application, 3 seedling plants of each species were hand planted into the soil in a 76 cm x 76 cm spacing per plant. A native plant nursery supplied all native plant seedlings used

PAGE 29

16 in the studies,1 and the two Eucalyptus species were obtained from Dr. Don Rockwood of the University of Florida.2 Common name, scientific name, and plant size at time of transplanting for all species are listed in Table 2.1. All species were evaluated for percent mortality at 10 weeks after planting. In addition, several species were evaluated for percent injury at 6 and 10 weeks after planting where 0 = no injury and 100 = plant death. Data were subjected to analysis of variance to test for main effects and interactions. Regression analysis was used to predict species response to imazapyr. Results and Discussion There was a significant interaction (p< 0.05) between experiments; therefore data for the two studies are reported separately. Of the 13 species used in the revegetation study, only 7 were observed for percent injury in each experiment. These seven species showed the greatest range of injury over the varying levels of imazapyr in the soil. Mortality ratings were recorded for all 13 species. Mortality data for experiment 1 are shown in Table 2.2. Regression analysis was used to predict the mortality response to imazapyr for each species. P60 values were calculated to define the highest amount of imazapyr in the soil at which at least 40% of plants remaining alive. Due to the slow activity of imazapyr, only the 10 WAP data is shown to allow for greatest plant response and possible recovery. In this experiment, only E. amplifolia showed less than 60% mortality at all rates of imazapyr, followed by M. strigillosa, which could tolerate imazapyr up to 0.82 kg ai/ha. P. palustris and E. grandis had P60 values of 0.443 and 0.381 kg ai/ha, which were still significantly greater 1 The Natives, Inc., Davenport, FL, USA. 2 Professor of Tree Improvement, University of Florida School of Forest Resources and Conservation, Gainesville, FL, USA.

PAGE 30

17 than the other species listed in Table 2.2. P. graminifolia and A. beyrichiana had P60 values of 0.17 and 0.11 kg ai/ha imazapyr, while Q. geminata, A. virginicus, L. mixhauxii, and E. spectabilis were the most sensitive to imazapyr with P60 values from 0.066 to 0.041 kg ai/ha imazapyr. Only M. cerifera showed greater than 60% mortality ratings at all levels of imazapyr in the soil, but this could be reflective of low transplant survival, not necessarily sensitivity to imazapyr. Mortality data for experiment 2 are shown in Table 2.3. In this experiment, most species showed greater tolerance to imazapyr than in experiment 1, which is reflected in greater P60 values. E. amplifolia, E. grandis, M. strigillosa, and L. michauxii all showed less than 60% mortality at all rates of imazapyr. A. beyrichiana showed a tolerance up to 0.974 kg ai/ha, followed by P. graminifolia and P. virgatum, with values of 0.773 and 0.739 kg ai/ha, respectively. A. virginicus was moderately sensitive with a P60 value of 0.544 kg ai/ha, followed by Q. geminata and E. spectabilis (0.437 and 0.325 kg ai/ha imazapyr). Data for Q. incana had such high variability that a response could not be calculated. P. palustris and M. cerifera showed greater than 60 % mortality ratings at all levels of imazapyr in the soil. Only 10 WAP injury data were recorded in experiment 1. All seven species evaluated exhibited an exponential increase in injury score in response to imazapyr injury. In Table 2.4, I30 values were calculated for species 10 WAP. These are values of imazapyr in soil (kg ai/ha) that cause no more than 30% injury to the plant species. Andropogon virginicus showed immediate dose response at very low concentrations increasing up to 0.15 kg ai/ha imazapyr (Figure 2.1), with injury of 83%. Injury levels did not increase dramatically as the rates increased from 0.15 to the maximum rate of

PAGE 31

18 1.12 kg ai/ha. A. virginicus exhibited 20% injury in the plots where there was no imazapyr, which might be reflective of transplant stress. Mimosa strigillosa and Aristida beyrichiana exhibited a more gradual response to imazapyr with increasing herbicide concentration (Figures 2.2 and 2.3), although M. strigillosa showed less injury at 0.4 kg ai/ha than A. beyrichiana (63% and 90%, respectively). A. beyrichiana also showed injury (38%) in areas where there was no imazapyr, again reflective of potential transplant stress of the seedlings. Pityopsis graminifolia also had a relatively high injury rate at 0.2 and 0.4 kg ai/ha (78 and 90% injury) as seen in Figure 2.4. Eucalyptus amplifolia and E. grandis, the two energy crop species, had comparatively low injury responses at 0.2 kg ai/ha (66 and 60%, respectively) when compared to the other species in the study (Figures 2.5 and 2.6). Also, Panicum virgatum showed 69% injury at 0.2 kg ai/ha (Figure 2.7). Of the 7 species, M. strigillosa, E. amplifolia, and E. grandis showed the lowest injury ratings at 0.2 kg ai/ha (no greater than 66%). For experiment 2, both 6 and 10 WAP injury data were recorded. Once again, the relationship between injury and imazapyr rate was exponential, but overall percent injury per concentration was lower in this experiment. In Table 2.5, I30 values were calculated for species 10 WAP. These are the highest values of imazapyr in soil (kg ai/ha) that cause no more than 30% injury to the plant species. A. beyrichiana and P. graminifolia showed the lowest injury at 0.2 kg ai/ha of all the 7 species monitored (41 and 40%, respectively) at 6 WAP, shown in Figures 2.10 and 2.11. Even at the highest rate of 0.4 kg ai/ha imazapyr, these two species show a minimal increase in injury (60% injury for A. beyrichiana and 55% for P. graminifolia) at 6 WAP. At 10 WAP, these two species have only a slight increase in injury at 0.4 kg ai/ha (64% for both species), as shown in

PAGE 32

19 Figures 2.17 and 2.18. M. strigillosa follows a similar trend, with 44% injury at 0.2 kg ai/ha and 59% injury at 0.4 kg ai/ha 6 WAP (Figure 2.9). At 6 WAP, M. strigillosa showed no greater than 78% damage at the maximum rates of imazapyr. M. strigillosa showed no significant change in reported injury between 6 and 10 WAP for rates of 0.4 kg ai/ha imazapyr (59 and 61%, respectively). A. virginicus showed 33% injury at 6 WAP in plots with no imazapyr, as well as 39% injury in the same plots 10 WAP. This high rate of injury is thought to be related to either transplanting or water stress (due to three days without watering immediately after transplanting in experiment 2). E. amplifolia and E. grandis showed higher rates of injury compared to experiment 1 at 0.4 kg ai/ha for both 6 and 10 WAP, as shown in Figures 2.12, 2.13, 2.19, and 2.20. E. amplifolia exhibited 76 and 78% injury at 0.4 kg ai/ha at 6 and 10 WAP, while E. grandis exhibited 75 and 80% injury at 6 and 10 WAP. P. virgatum had a marked increase in injury from 6 to 10 WAP for both 0.2 and 0.4 kg ai/ha imazapyr, as shown in Figures 2.14 and 2.21 (44 and 65% 6 WAP and 57 and 74% 10 WAP). Overall, both Eucalyptus species, M. strigillosa, A. beyrichiana, and P. graminifolia show low mortality response to imazapyr in soil. However, E. amplifolia and E. grandis both show higher injury response than many other species to imazapyr in this study. These data show that these species might be able to outgrow the imazapyr injury after some period of time. Even though a plant might show initial injury symptoms, the overall ability of that plant to recover is a very important quality to look for in a potential revegetation species. In addition to these data regarding the most tolerant species to be used as revegetation species, it is important to consider the costs involved with transplanting, as

PAGE 33

20 well as the overall desirability of the species by landowners. These data are beneficial from a research standpoint, but economic aspects should be taken into consideration as well.

PAGE 34

21 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100120 y=87.9*(1-exp(-24.7*x)) R2=0.87 Figure 2.1. Andropogon virginicus (broomsedge) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1. Means of 4 replications present with standard error.

PAGE 35

22 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=42.8*(1-exp(-17.5*x))+69.1*(1-exp(-0.9*x)) R2=0.96 Figure 2.2. Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application. Experiment initiated on June 22, 2004, in Citra, Florida. Means of 12 replications present with standard error.

PAGE 36

23 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100120 y=86.2*(1-exp(-21.8*x)) R2=0.21 Figure 2.3. Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1. Means of 4 replications present with standard error.

PAGE 37

24 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100120 y=91.3*(1-0.0^*x)) R2=0.67 Figure 2.4. Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1. Means of 4 replications present with standard error.

PAGE 38

25 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100120 y=86.0*(1-exp(-8.5*x)) R2=0.97 Figure 2.5. Eucalyptus amplifolia response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1. Means of 4 replications present with standard error.

PAGE 39

26 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100120 y=34.2*(1-exp(-23.7*x))+61.1*(1-exp(-2.9*x)) R2=0.97 Figure 2.6. Eucalyptus grandis response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1. Means of 4 replications present with standard error.

PAGE 40

27 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100120 y=90.6*(1-exp(-9.9*x)) R2=0.94 Figure 2.7. Panicum virgatum (switchgrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 1. Means of 4 replications present with standard error.

PAGE 41

28 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100120 y=32.7+25.0*(1-exp(-14.5*x))+149557.6*(1-exp(-0.0002*x)) R2=0.61 Figure 2.8. Andropogon virginicus (broomsedge) response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 42

29 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=19.4+63.2*(1-exp(-2.8*x)) R2=0.75 Figure 2.9. Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 43

30 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=12.0+77.7*(1-exp(-2.7*x)) R2=0.94 Figure 2.10. Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 44

31 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=33.9+64.5*(1-exp(-1.6*x)) R2=0.69 Figure 2.11. Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 45

32 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=85.1*(1-exp(-7.4*x)) R2=0.91 Figure 2.12. Eucalyptus amplifolia response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 46

33 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=86.4*(1-exp(-5.9*x)) R2=0.95 Figure 2.13. Eucalyptus grandis response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 47

34 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=85.2*(1-exp(-4.3*x)) R2=0.96 Figure 2.14. Panicum virgatum (switchgrass) response to imazapyr concentration in soil 6 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 48

35 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100120 y=39.2+45.3*(1-exp(-5.9*x)) R2=0.41 Figure 2.15. Andropogon virginicus (broomsedge) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 49

36 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=12.9+67.5*x^0.33 R2=0.74 Figure 2.16. Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 50

37 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=5.5+22.8*(1-exp(-60.4*x))+63.5*(1-exp(-2.6*x)) R2=0.97 Figure 2.17. Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 51

38 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=27.5+59.9*x^0.5 R2=0.75 Figure 2.18. Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 52

39 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=10.2+27.6*(1-exp(-42.3*x))+55.7*(1-exp(-3.6*x)) R2=0.81 Figure 2.19. Eucalyptus amplifolia response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 53

40 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 injury (%) 020406080100 y=6.1+85.8*(1-exp(-5.5*x)) R2=0.92 Figure 2.20. Eucalyptus grandis response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error.

PAGE 54

41 imazapyr concentration (kg ai/ha) 0.00.20.40.60.8 1.01.2 injury (%) 02040 6080100 Figure 2.21. Panicum virgatum (switchgrass) response to imazapyr concentration in soil 10 WAP (weeks after planting) immediately after imazapyr application for experiment 2. Means of 4 replications present with standard error. y=14.6+77.4*(1-exp(-4.6*x)) R2=0.82

PAGE 55

Table 2.1. Species used in revegetation study in Citra, Florida. 42 common name scientific name size of seedlings broomsedge Andropogon virginicus 10 centimeter tublings mimosa Mimosa strigillosa 10 centimeter pots sand live oak Quercus geminata 1 liter pots bluejack oak Quercus incana 1 liter pots wiregrass Aristida beyrichiana 10 centimeter tublings silkgrass Pityopsis graminifolia 10 centimeter tublings gopher apple Licania michauxii 5 centimeter cups wax myrtle Myrica cerifera 2.5 centimeter x 7.5 centimeter (tray) lovegrass Eragrostis spectabilis 10 centimeter tublings longleaf pine Pinus palustris 2.5 centimeter x 7.5 centimeter (tray) switchgrass Panicum virgatum 10 centimeter tublings Eucalyptus grandis Eucalyptus grandis 15 centimeter tublings Eucalyptus amplifolia Eucalyptus amplifolia 15 centimeter tublings

PAGE 56

Table 2.2. The effect of imazapyr soil concentration on percent mortality of selected revegetation species 10 weeks after planting. Experiment 1 initiated on June 22, 2004, in Citra, FL. P60 values reflect the predicted imazapyr concentration that would result in less than 60% mortality. 43 Plant Species Regression Equation R2 P60 imazapyr values (kg ai/ha) Eucalyptus amplifolia y=(-5518.4)+5614.4*exp(-0.0062*x) 0.78 > 1.12 mimosa y=101.3*exp(-1.1*x) 0.99 0.82 longleaf pine y=96.1*exp(-2.0*x) 0.97 0.443 Eucalyptus grandis y=5.2+88.8*exp(-2.5*x) 0.87 0.381 silkgrass y=10.1+55.3*exp(-3.6*x) 0.65 0.17 wiregrass y=1.8+56.8*exp(-3.6*x) 0.68 0.11 sand live oak y=25.2+22.7*exp(-6.3*x) 0.18 0.066 broomsedge y=43.3*exp(-20.5*x)+27.6*exp(-0.15*x) 0.60 0.058 gopher apple y=15.5+38.6*exp(-7.7*x) 0.65 0.058 lovegrass y=(-1.9)+59.0*exp(-7.9*x) 0.95 0.041 bluejack oak y=41.2*exp(-4.7*x) 0.85 0.0044 switchgrass y=10.9+34.9*exp(-39.0*x) 0.59 0.0043 wax myrtle y=35.6*exp(-4.9*x) 0.47 *Species exhibits greater than 60% mortality at all rates of imazapyr in soil.

PAGE 57

Table 2.3. The effect of imazapyr soil concentration on percent mortality of selected revegetation species 10 weeks after planting. Experiment 2 initiated on July 21, 2004, in Citra, FL. P60 values reflect the predicted imazapyr concentration that would result in less than 60% mortality. 44 Plant Species Regression Equation R2 P60 imazapyr values (kg ai/ha) Eucalyptus amplifolia y=93.7+(-58.5)*x+14.7*x^2 0.75 >1.12 mimosa y=88.8+10.0*exp(-3.7*x) 0.26 >1.12 Eucalyptus grandis y=98.2+(-6.3)*x+(-16.9)*x^2 0.81 >1.12 gopher apple y=69.5+6.2*x 0.12 > 1.12 wiregrass y=92.3+(-12.9)*x+(-53.9)*x^2 0.90 0.974 silkgrass y=(-501.5)+577.9*exp(-0.09*x) 0.67 0.773 switchgrass y=95.7+(-81.3)*x+(-3.2)*x^2 0.67 0.739 broomsedge y=(-1177.7)+1240.1*exp(-0.04*x) 0.31 0.544 sand live oak y=37.5+16.0*exp(-2.7*x) 0.05 0.437 lovegrass y=87.8+(-192.9)*x+104.9*x^2 0.96 0.325 bluejack oak NS --longleaf pine y=38.7*exp(-1.6*x) 0.78 wax myrtle y=39.9+(-105.9)*x+74.2*x^2 0.63 *Species exhibits greater than 60% mortality at all rates of imazapyr in soil.

PAGE 58

Table 2.4. The effect of imazapyr soil concentration on percent injury of selected revegetation species 10 weeks after planting. Experiment 1 initiated on June 22, 2004, in Citra, FL. I30 values reflect the highest predicted imazapyr concentration that would cause no greater than 30% injury. 45 Plant Species Regression Equation R2 I30 imazapyr values (kg ai/ha) Eucalyptus grandis y=34.2*(1-exp(-23.7*x))+61.1*(1-exp(-2.9*x)) 0.97 0.063 Eucalyptus amplifolia y=86.0*(1-exp(-8.5*x)) 0.97 0.056 mimosa y=42.8*(1-exp(-17.5*x))+69.1*(1-exp(-0.9*x)) 0.96 0.055 switchgrass y=90.6*(1-exp(-9.9*x)) 0.94 0.037 broomsedge y=87.9*(1-exp(-24.7*x)) 0.87 0.014 silkgrass y=91.3*(1-0.0^*x)) 0.67 0.012 wiregrass y=86.2*(1-exp(-21.8*x)) 0.21 *Species exhibits greater than 30% injury at all rates of imazapyr in soil.

PAGE 59

46 Table 2.5. The effect of imazapyr soil concentration on percent injury of selected revegetation species 10 weeks after planting. Experiment 2 initiated on July 21, 2004, in Citra, FL. I30 values reflect the highest predicted imazapyr concentration that would cause no greater than 30% injury. Plant Species Regression Equation R2 I30 imazapyr values (kg ai/ha) Eucalyptus grandis y=6.1+85.8*(1-exp(-5.5*x)) 0.92 0.066 switchgrass y=14.6+77.4*(1-exp(-4.6*x)) 0.82 0.041 wiregrass y=5.5+22.8*(1-exp(-60.4*x))+63.5*(1-exp(-2.6*x)) 0.97 0.034 Eucalyptus amplifolia y=10.2+27.6*(1-exp(-42.3*x))+55.7*(1-exp(-3.6*x)) 0.81 0.024 mimosa y=12.9+67.5*x^0.33 0.74 0.017 silkgrass y=27.5+59.9*x^0.5 0.75 broomsedge y=39.2+45.3*(1-exp(-5.9*x)) 0.41 *Species exhibits greater than 30% injury at all rates of imazapyr in soil.

PAGE 60

CHAPTER 3 IMAZAPYR RESIDUAL MEASUREMENTS USING CORN ROOT BIOASSAY Introduction Cogongrass [Imperata cylindrica (L.) Beauv.], an aggressive perennial grass species which infests over 500 million hectares worldwide, is considered the worlds seventh worst weed (Holm et al. 1977). In the United States, cogongrass infests several hundred thousand acres and it is widely spread throughout Florida and much of southern Alabama and Mississippi (Johnson et al. 1999). Cogongrass can usually be found in predominately non-agricultural settings in the United States., and this aggressive weed tends to spread over vast areas where vegetation is marginally supported, suppressing and displacing many native plants (Bryson and Carter 1993). Cogongrass tolerates a wide range of soil conditions but appears to grow best in soils with acidic pH, low fertility, and low organic matter. Several survival strategies lend to this invasive plants ability to spread and persist, including an extensive rhizome system, adaptation to poor soils, drought tolerance, fire adaptability, and high genetic plasticity (Holm et al. 1977, Dozier et al. 1998). Current control methods for cogongrass rely heavily on chemical treatment, which unfortunately provides limited long-term control unless used in conjunction with revegetation. The most effective herbicides for cogongrass management are glyphosate and imazapyr (Dozier et al. 1998; Barnett et al. 2000; MacDonald et al. 2002). Imazapyr is used to control annual and perennial weeds, deciduous trees, and vines in rights-of-way and other noncropland areas, as well as in forestry as a conifer releasing agent (Anon. 47

PAGE 61

48 2002). The mode of action of imazapyr, a member of the imidazolinone family of herbicides, involves the inhibition of acetohydroxyacid synthase (AHAS), which is needed for synthesis of branched chain amino acids (Shaner 1991). Field half-life values range from 25-142 days depending on soil type and environmental conditions, with soil adsorption increasing as organic matter and clay content increase (Anon. 2002). Imazapyr is relatively harmless to animals and has minimal off-target impacts if used correctly (Mangels 1991). Compared to glyphosate, imazapyr generally provides control for a longer period of time due to soil activity (MacDonald et al. 2002), and research to date has indicated imazapyr at 1.12 kg-ai/ha applied late summer/early fall provides control for as long as 18 months (Dozier et al. 1998). Burning prior to herbicide application has also proven effective, with benefits including weakened rhizomes due to re-allocation of starch reserves to new shoot growth and removal of old biomass. Herbicide application to the regrowth of new plant tissues maximizes absorption and results in greater efficacy (Johnson et al. 1999). Although there is ample information on the effect of several herbicides on weedy species, little information regarding the herbicide tolerance (i.e., selectivity potential) of native species is available. In previous research by Miller et al. (2002), several native species were evaluated under greenhouse conditions for response to imazapyr. Imazapyr caused severe injury to most species, but this injury was reflected to a foliar application only. In practical field situations, herbicides are usually sprayed to control cogongrass with little or no subsequent implementations such as revegetation. These areas often become reinfested because of a lack of suppressive cover.

PAGE 62

49 An important step in the further suppression of cogongrass is to establish a native plant cover into these sprayed areas as soon as the residual herbicide levels in the soil become tolerable to the plant. It is important to quantify these soil residual levels to best predict effective revegetation timing in order to effectively suppress cogongrass. One of the more popular tools for monitoring imidazolinone residues is through soil bioassay. Corn is highly sensitive to imidazolinone and sulfonylurea herbicides and has become the accepted bioassay species for the detection of these herbicides in soil (OBryan 1994). By using corn bioassay techniques, an understanding of plant species response to imazapyr residues in soil can be obtained. With these data, a prediction model can be calculated to determine how long it takes imazapyr levels in soil to reach a concentration that will be tolerable to the plant in question. This information will ultimately be beneficial for restoration purposes in southeastern ecosystems (MacDonald et al. 2002). Soil type plays an important role in residual herbicide levels due to its structure and content of clay and organic matter. In sandy soils, there are fewer charged sites that the herbicide can adsorb to, and leaching occurs more often. Therefore, sandy soils contain less residual matter after a given period of time than a clay soil, which has a much greater affinity for adsorption. Herbicides also tend to persist longer in loamy and silty soils due to less leaching compared to sandy soils. In central Florida, reclaimed mining sites have a diverse collection of soil types with overburden, sand tailings and phosphatic clay pits being three of the most prominent. Overburden, a mixture of sand and clay, is removed from the land surface to the top of the ore body and piled on the side. Overburden shows the highest variability in soil texture, soil color and soil chemical parameters (Segal et al. 2001). This soil type is

PAGE 63

50 on average composed of 80% sand, 8% silt, and 12% clay with a pH of 5.8.1 Overburden has slightly greater clay and silt content, higher water-holding capacity, and greater P and K content than native Floridian soils, which may give aggressive weeds a competitive advantage over slower-growing natives (Richardson et al. 2003). The phosphate ore currently being mined is an unconsolidated mixture of sand, clay, and phosphate mineral. The sand tailings are separated from this ore and hydraulically pumped to fill mine cuts between overburden piles. Although sand tailings are usually nutrient-poor and droughty compared with these three other soil types (Segal et al. 2001), they have higher P and K contents and slightly coarser grain sizes than native soils (Kluson et al. 2000). Phosphatic clay is washed from phosphate ore and pumped, at about 3-5% solids, to settling areas. This clay commonly has pH values near 7.5, while some older sites with good forest cover and higher organic matter have pH values near 6.8. This soil type covers about 40% of the mined area and is considered highly fertile (Stricker 2000). Imazapyr provides good control of cogongrass but has limited utility due to the long residual effects of this compound, which could hinder revegetation strategies. Initial research indicates the residual activity of this compound may be less than theorized, allowing for more flexibility in a revegetation scheme. Because of the diversity of soils in Florida, as well as much of the U.S., an understanding of herbicide persistence as a function of soil type would be important to predict the best time for revegetation. By taking samples of the three distinct types of soil after a certain amount of time after herbicide application, information on residue amounts can be generated. With such 1 Richardson, S.G. 2004. Personal Communication.

PAGE 64

51 residual data, a timetable could be calculated to best predict when revegetation should occur. Materials and Methods Research was conducted at Tenoroc Fish Management Area, a 2,430-hectare tract of land that was mined for phosphate until the mid-1970's. The area is located 3.2 kilometers northeast of Lakeland, Florida. Approximately 4000 hectares of lakes locally referred to as "phosphate pits" remained from early mining operations. This area has three distinct soil types that were results of the mining process: sand tailings, overburden, and phosphatic clay settling ponds. Studies were conducted on each of the three soil types to gain better understanding of imazapyr persistence in each of these areas. In each of the three soil types, a total area of 24 x 30 meters was mowed in October 2002, immediately before herbicide application. The plots measured 6 x 6 meters in a randomized complete block design with 5 replications. Treatments were applied using a CO2 backpack sprayer with 11002 flat fan nozzles calibrated to deliver 187 L/ha. The treatments were 0.84, 1.68, and 3.36 kg ai/ha imazapyr2 with an untreated check. Both the overburden and sand areas were sprayed on November 19, 2002, while the clay settling area was sprayed December 12, 2002. Within each plot for all 3 areas, a total of 10, 2.5-cm diameter, 15-cm deep soil cores were randomly taken. Sampling occurred immediately prior to application, immediately after application, and at 1, 3, 6, and 12 months after application. Samples were put in labeled plastic freezer bags and placed on 2 Arsenal 4 Applicators Concentrate (AC), BASF, USA.

PAGE 65

52 ice for transport to Gainesville. These soil samples were stored frozen at -20C until bioassay work was performed. Imazapyr concentration was determined using a corn-root bioassay, which was conducted in the greenhouse at the Gainesville campus. Individual frozen soil samples from each location were thawed, dried, and equally distributed into 3 cone shaped vessels (Cone-tainers, 40 x 200 mm)3 which were used as growth containers. Each bioassay experiment was conducted with an accompanying series of imazapyr concentrations which allowed for the development of a standard response curve. To develop this curve, untreated soil from each of the three locations was sifted through a 2mm screen and air dried for 3 days. Soils were put in small pots (10 x 15 cm) to simulate the surface area of the previous field sampling. Known amounts of imazapyr were applied to the samples using a CO2 backpack sprayer with 11002 flat fan nozzles calibrated to deliver 187 L/ha. For these standards, a wide range of imazapyr rates were applied: 0.0, 0.018, 0.036, 0.071, 0.14, 0.28, 0.56, and 1.12 kg ai/ha. This was performed because imazapyr in the original field samples would decrease as the sampling continued over time. Having lower concentrations in the standard response curve component would aid in accuracy of predicted concentration. After imazapyr rates were sprayed, treated soil was equally mixed in a plastic bag and similarly divided into 3 Cone-tainers. Seeds of field corn4 were pre-germinated by placement under wet paper towels for 2-3 days. For all field and standard samples, one pre-germinated corn seed (radical 3 Cone-Tainer Nursery, 150 North Maple, Canby, OR 97013. 4 Pioneer 33J 56.

PAGE 66

53 length approximately 0.5 cm) was planted 2 cm below the soil surface. The soil-filled cone-tainers were immediately subirrigated to field capacity and then placed in a greenhouse environment of 16 hours daylight and 8 hours darkness at 30C mean temperature. After 9 days, corn seedlings were removed, washed, and primary root length measured. Regression equations were calculated to best fit the recorded data. Results and Discussion Only 0, 1 and 3 month after treatment (MAT) soil samples were successfully utilized using corn root bioassay. Standard curves were calculated each time a bioassay was performed and are shown in the Appendix. These generated regression equations are shown on each graph, along with adjusted R2 values. Corn root data were fitted to the corresponding regression equations and the predicted values of imazapyr in the soil are listed in Tables 3.1, 3.2, and 3.3. In all three areas sprayed, detected residues were substantially lower than expected. This can especially be seen in the 0 MAT data, where significantly low levels of imazapyr were detected immediately after application. This could be due to a dense vegetative cover found in the areas during herbicide application, which might have prevented imazapyr from fully reaching the soil surface. Vegetative cover, either as dead biomass or thatch, is common in areas chemically treated for cogongrass. This might be beneficial in revegetation planning since soil imazapyr residues might be lower than expected due to this foliar uptake. Sand tailing data for all samples taken at 0, 1, and 3 MAT were averaged and replications were combined. This combined data are shown in Table 3.1. At the lowest application rate of 0.84 kg ai/ha, the soil samples average a consistently similar rate at 0 MAT. At 1 MAT of the 0.84 kg ai/ha, there was no detection of imazapyr, and a trace

PAGE 67

54 amount was detected at 3 MAT (0.003 kg ai/ha). In the areas sprayed with 1.68 and 3.36 kg ai/ha, 1.12 kg ai/ha were predicted for sand tailings at 0 MAT. Since the maximum rate of the standards was 1.12 kg ai/ha, no greater value could be comparatively quantified. For 1 MAT, predicted imazapyr values were 0.011 and 0.026 kg ai/ha for the 1.68 and 3.36 kg ai/ha sand tailing applications. In the 1.68 kg ai/ha areas, imazapyr rates were reduced at 3 MAT (0.003 kg ai/ha). For the replications treated with 3.36 kg ai/ha, a reduction was seen 3 MAT (0.0087 kg ai/ha). In the clay soil, higher concentrations of imazapyr than in the sand tailings area were detected 3 MAT in the areas treated with 1.68 and 3.36 kg ai/ha (Table 3.2). For all treatments, samples taken 0 MAT were similar in value (0.062, 0.064, and 0.054 kg ai/ha for the plots sprayed with 0.84, 1.68, and 3.36 kg ai/ha, respectively). This inconsistent data could be credited to the variability of the soil sampling techniques. Soil imazapyr residues were continually reduced at 1 and 3 MAT for all treatments in the clay soil. In the overburden soil, 0 MAT residues were greater than those of the clay and less than those in the sand area (Table 3.3). For the area sprayed with 0.84 kg ai/ha, residues decreased to 0.018 kg ai/ha 1 MAT and 0.01 kg ai/ha 3 MAT. The plots treated with 1.68 kg ai/ha also decreased to 0.027 kg ai/ha 1 MAT and 0.015 kg ai/ha 3 MAT. Finally, plots treated with 3.36 kg ai/ha were reduced to 0.033 kg ai/ha 1 MAT and 0.025 kg ai/ha 3 MAT. Overall, imazapyr concentration was more quickly reduced in sand tailings. Mixed results occur between clay and overburden soil. This overall decreased concentration of imazapyr in the soil is expected, and the different rates and change with concentrations among soil types are useful data for selecting successful revegetation species.

PAGE 68

55 These bioassay data, coupled with the plant species injury and mortality data from Chapter 2, were used to create a timetable to best estimate optimal planting dates per species. The dates reflect the estimated time it takes for imazapyr residues in soil to decrease to a tolerable level for the plants. Estimated time intervals are expressed in months after treatment (MAT) and were estimated from the predicted P60 and I30 values for each species. These data are based on an imazapyr application rate of 0.84 kg ai/ha and are shown in Tables 3.4 and 3.5 (Experiment 1 and 2, respectively). Regression figures and equations are also shown in the Appendix. As seen in Table 3.1, no correlation can be found among the measurements taken in the sand area sprayed with 0.84 kg ai/ha imazapyr. This is because imazapyr was not detected 1 MAT, yet trace amounts were detected 3 MAT. For this reason, only estimations for clay and overburden areas were formulated. In both the clay and overburden area in Experiment 1, six species can be planted immediately after imazapyr application and expect to show at least a 40% survival rate 10 WAP (P60). These species are E. amplifolia, mimosa, longleaf pine, E. grandis, silkgrass, and wiregrass. Sand live oak, broomsedge, and gopher apple show some sensitivity, therefore at least one month should be waited before planting. Lovegrass should be planted at least one month after treatment, while bluejack oak and switchgrass have significantly longer times of 3 MAT to allow for at least 40% survival. Since wax myrtle showed greater than 60% mortality at all imazapyr rates in both experiments, no predicted plantback date could be given within the limit of 60 days. In Experiment 2, all plant species show at least 40% survival in both soil types immediately after application. In addition to wax myrtle, switchgrass

PAGE 69

56 shows greater than 60% mortality at all rates in Experiment 2, therefore no date could be predicted. Predicted dates according to injury data from Chapter 2 (I30 values) are listed for the seven monitored species for Experiment 1 and 2, as well. In Experiment 1 (Table 3.4), E. grandis can be planted 1 MAT in clay and 1 MAT in overburden to exhibit no more than 30% injury 10 WAP. E. amplifolia, mimosa, and bluejack oak also show slightly longer time periods for I30 predictions in overburden soils as compared to clay soils. Silkgrass and broomsedge have the longest delay in planting until soil residues are within range of I30 values (3 MAT in clay and 3 MAT in overburden). Wiregrass shows at least 30% injury at all rates of imazapyr, so no predicted date could be made within the range of 60 days. Experiment 2 (Table 3.5) shows similar predicted dates according to I30 values for E. grandis and switchgrass, although E. amplifolia, mimosa, and wiregrass show increased predicted plantback time (MAT) in which soil residues cause no more than 30% injury in both clay and overburden areas. These extended dates are in contrast with those for silkgrass and broomsedge, in which all rates of imazapyr caused at least 30% injury in Experiment 2. Therefore, no predicted dates could be made for these species since the study range was only 60 days. Based on the plant-back time in relation to injury data, E. grandis and switchgrass are good candidates for use in revegetation planning. Several additional species, including E. amplifolia, mimosa, longleaf pine, silkgrass, and wiregrass, would be good choices in a plantback scenario if percent mortality is a more desirable quality than injury. These predicted plantback dates after initial imazapyr application will be helpful in determining optimum timing of a revegetation project. Knowing what species will

PAGE 70

57 best tolerate imazapyr and how long to wait before planting can reduce the gap of time between initial cogongrass control and its reinvasion of an area.

PAGE 71

58 Table 3.1. The predicted concentration values of imazapyr using a corn root bioassay from sand tailings soil in Polk County. Months after treatment Application rate 0 1 1 2 3 3 --------------------------------------kg ai/ha -----------------------------------0 0 0 0 0.84 0.84 0.334 0 0.003 0 1.68 1.12 0 0.011 0.01 0.003 0 3.36 1.12 0 0.026 0.01 0.0087 0.01 1 Values derived from regression equation y=2.3+12.3*exp (-26.7*x); R2= 0.87; See Figure A-1. 2 Values derived from regression equation y=1.7+13.6*exp (-28.9*x); R2=0.95; See Figure A-2. 3 Values derived from regression equation y=2.0+10.8*exp (-44.0*x); R2=0.97; See Figure A-3. 4 Mean of 5 replications followed by Standard Deviation. Table 3.2. The predicted concentration values of imazapyr using a corn root bioassay from clay soil in Polk County. Months after treatment Application rate 0 1 1 2 3 3 --------------------------------------kg ai/ha -----------------------------------0 0 0 0 0.84 0.062 0.014 0.013 0.01 0.0018 0 1.68 0.064 0.02 0.044 0.01 0.023 0.02 3.36 0.054 0.02 0.032 0.02 0.02 0.02 1 Values derived from regression equation y=1.7+15.2*exp(-40.5*x); R2= 0.83; See Figure A-4. 2 Values derived from regression equation y=1.4+16.4*exp(-36.7*x); R2=0.97; See Figure A-5. 3 Values derived from regression equation y=1.5+12.1*exp(-23.3*x); R2=0.90; See Figure A-6. 4 Mean of 5 replications followed by Standard Deviation.

PAGE 72

59 Table 3.3. The predicted concentration valu es of imazapyr using a corn root bioassay from overburden soil in Polk County. Months after treatment Application rate 0 1 1 2 3 3 -------------------------------------kg ai/ha ---------------------------------0 0 0 0 0.84 0.29 0.294 0.018 0.01 0.01 0.01 1.68 0.17 0.17 0.027 0.02 0.015 0.01 3.36 0.36 0.36 0.033 0.01 0.025 0.02 1 Values derived from regression equation y =2.0+12.6*exp(-28.3*x); R2= 0.95; See Figure A-7. 2 Values derived from regression equation y =1.6+11.8*exp(-33.0*x); R2=0.94; See Figure A-8. 3 Values derived from regression equation y =0.9+12.7*exp(-32.7*x); R2=0.93; See Figure A-9. 4 Mean of 5 replications followed by Standard Deviation.

PAGE 73

60 Table 3.4. Estimated revegetation timeframe as related to plant species and soil type according to Experiment 1. Clay Overburden P 40 Mortality I30 Injury P40 Mortality I30 Injury Plant Species --------------Months after imazapyr application (0.84 kg ai/ha) in soil------------Eucalyptus amplifolia 0 1 0 1 mimosa 0 1 0 1 longleafpine 0 -0 -Eucalyptus grandis 0 1 0 1 silkgrass 0 3 0 3 wiregrass 0 0 sand live oak 1 -1 -broomsedge 1 3 1 3 gopherapple 1 -1 -lovegrass 1 -1 -bluejackoak 3 -3 -switchgrass 3 1 3 1 waxmyrtle -* -* Time for imazapyr rate to become tolerable at the specified value exceeds period of monitoring.

PAGE 74

61 Table 3.5. Estimated revegetation timeframe as related to plant species and soil type according to Experiment 2. Clay Overburden P 40 Mortality I30 Injury P40 Mortality I30 Injury Plant Species --------------Months after imazapyr application (0.84 kg ai/ha) in soil------------Eucalyptus amplifolia 0 1 0 1 mimosa 0 3 0 3 longleafpine 0 -0 -Eucalyptus grandis 0 1 0 1 silkgrass 0 0 wiregrass 0 1 0 1 sand live oak 0 -0 -broomsedge 0 0 gopherapple 0 -0 -lovegrass 0 -0 -bluejackoak 0 -0 -switchgrass 1 1 waxmyrtle -* -*Time for imazapyr rate to become tolerable at the specified value exceeds period of monitoring.

PAGE 75

CHAPTER 4 NATURAL RECRUITMENT OF PLANT SPECIES IN AREAS PREVIOUSLY INFESTED WITH COGONGRASS Introduction Cogongrass [Imperata cylindrica (L.) Beauv.] is a rhizomatous perennial grass species found throughout much of the tropical and sub-tropical regions of the world and is considered to be the worlds seventh worst weed (Holm et al. 1977). Unfortunately, the occurrence of cogongrass has increased drastically during the past twenty years (Bryson and Carter 1993) and is currently reported in much of the southeast United States, including Florida, Mississippi, and Alabama (Johnson et al. 1999). Cogongrass tends to spread over vast areas where vegetation is marginally supported, suppressing and displacing many native plants (Bryson and Carter 1993). Cogongrass is able to spread and persist through several survival strategies including an extensive rhizome system, adaptation to poor soils, drought tolerance, prolific wind disseminated seed production, fire adaptability, and high genetic plasticity (Holm et al. 1977; Dozier et al. 1998). Invasive, non-native weeds such as cogongrass are a cause for concern in natural areas within the United States. Once aggressive weeds such as this become established in an area, they may continue to proliferate and displace most of the native vegetation, many times resulting in a monoculture of cogongrass (Shilling et al. 1997). Invasive weeds can displace native plants by growing and reproducing more rapidly and being less sensitive to environmental stresses than native species (Marion 1986). Native xeric scrub and sand hill species commonly found throughout Florida typically grow slowly and provide low 62

PAGE 76

63 coverage. This is due to low moisture and fertility inherent in xeric soils, which allows for an open niche for invasive species (Segal et al. 2001). Once an invasive species dominates an area, natural fire and hydrology processes that influence the ecosystem may be altered. There is often less pressure placed upon these non-native species from disease, insects, or predation since they did not naturally evolve in these areas. Non-native invasive plants are often able to thrive when outside pressures are removed. In Florida, reclaimed phosphate mining areas are important areas for cogongrass control and native plant restoration. Because mining disturbance creates a hospitable environment for weed invasion, one of the most difficult barriers to successful restoration is the control of cogongrass and other invasive weeds. In central Florida, reclaimed mining sites have a diverse collection of soil types with overburden, sand tailings and phosphatic clay pits being three of the most prominent (Richardson et al. 2003). Overburden, a mixture of sand and clay, is removed from the land surface to the top of the ore body and piled on the side. Phosphate ore, currently being mined, is an unconsolidated mixture of sand, clay, and phosphate mineral. Sand tailings are separated from the phosphatic ore and hydraulically pumped to fill mine cuts between overburden piles. Phosphatic clay is washed from phosphate ore and pumped, at about 3-5% solids, to settling areas. This soil type covers about 40% of the mined area and is considered highly fertile (Stricker 2000). These three soil types involved in phosphate mining processes are highly diverse in nature, yet they are all susceptible to cogongrass and other non-native weed invasions. This is due to the disturbance of the areas during the mining process and the associated harsh conditions to which plants are subjected.

PAGE 77

64 In phosphate reclamation areas and other natural areas, chemical weed control is the most common practice. Unfortunately, these herbicide control methods provide limited long-term control. To date, the most effective herbicides for cogongrass management are glyphosate and imazapyr (Dozier et al. 1998; Barnett et al. 2000; MacDonald et al. 2002). Generally, imazapyr provides control for a longer period of time due to soil activity and has minimal off-target effects if used correctly (MacDonald et al. 2002). Research to date has indicated imazapyr at 1.12 kg-ai/ha applied late summer/early fall provides control for as long as 18 months (Dozier et al. 1998). The main reason for this limited control is the presence of cogongrass rhizomes, which can comprise over 2/3 the total plant biomass. These rhizomes contain multiple nodes from which regrowth may occur, but generally only a fraction sprout at any given time (English 1998). This low shoot to root/rhizome ratio contributes to its rapid regrowth after cutting or burning (Sajise 1976). Cogongrass rhizomes are white and tough with shortened internodes. Specialized anatomical features help to conserve water within the central cylinder and help to resist breakage and disruption when trampling or disturbance occurs (Holm et al. 1977). Rhizomes are predominately found within the top 15 cm of fine textured soils or the top 40 cm of course textured soils. However, rhizomes have been discovered growing at depths of 120 cm (Holm et al. 1977; Gaffney 1996). According to Tominaga (2003), cogongrass rhizomes can be grouped in the following three categories: tillering, secondary colonizing, and pioneer rhizomes. Unlike cogongrass seedlings, which are defined as R-strategist (ruderal) and invade open patches in disturbed habitats, rhizomes from current cogongrass stands are more defined as C-strategist (competitor) that can persist in established populations (Tominaga 2003).

PAGE 78

65 These rhizomes provide a tremendous amount of biomass for regeneration after foliar loss, with one study showing rhizome length of over 89 meters within one square meter of soil surface area (Lee 1977). Cogongrass rhizomes are a major hindrance to continued suppression after initial control. For long-term management of cogongrass, further methods need to be integrated into the traditional control techniques that are currently used. Even in areas where initial control has been successful, cogongrass re-infestation will often occur. One objective of this study is to determine rhizome presence and density in areas previously treated with imazapyr and glyphosate, which will be helpful in understanding the mechanism of cogongrass re-infestation. In addition, the objective of monitoring natural recruitment of native species in areas previously treated with these herbicides may help us to understand which plant species are more competitive with cogongrass. This type of information will be beneficial in the long-term planning and management of natural areas for long-term cogongrass management and control. Materials and Methods Research was conducted at Tenoroc Fish Management Area, a 2,430-hectare tract of land that was mined for phosphate until the mid-1970's. The area is located 3.2 kilometers northeast of Lakeland, Florida. Approximately 400 hectares of lakes locally referred to as "phosphate pits" remain from early mining operations. Three areas previously infested with cogongrass were sprayed in the fall of 2000, 2001, and 2003, following a late summer (August) burn. Burning removed accumulated thatch and simulated regrowth. Cogongrass was 30-45 cm tall at the time of treatment.

PAGE 79

66 Long Term Cogongrass Control Treatments included imazapyr at 0.84 kg ai/ha and glyphosate at 3.36 kg ai/ha in 76 m long x 15 m wide plots with 4 replications. In January 2004, visual observations were taken in these areas to monitor cogongrass reinfestation 0.25, 2, and 3 years after initial treatment to determine which herbicide had the greatest control over time. Percent control was recorded, where 0 = no control and 100 = complete control. Data were subjected to analysis of variance to test for main effects and interactions. Rhizome Distribution In the area sprayed on October 16, 2000, 25 samples of 10 cm x 20 cm soil cores were taken from each of the 8 plots, approximately 3 years post-treatment (January 13, 2004). The samples were taken at random locations within each plot and categorized according to proximity to cogongrass regrowth: 1) samples where no cogongrass was present within 0.6 meters; 2) samples within 0.6 meters of cogongrass; and 3) samples within a cogongrass patch. This sampling date was chosen after several growing seasons to allow for any natural progression of annual and perennial species that might establish after initial cogongrass control. Soil samples were transported back to Gainesville, FL, for rhizome removal. After 3 days in an oven drier at 60C, rhizome dry weight was determined. Plant species were evaluated for percent cover within each plot, where 0 = no coverage and 100 = complete coverage, and data were subjected to analysis of variance to test for main effects and interactions. Native Species Recolonization In addition, the Tenoroc area has three distinct soil types that result from the mining process: sand tailings, overburden, and phosphatic clay settling ponds. Mowing occurred in October 2002 in each of the three soil types immediately before herbicide

PAGE 80

67 application, with treatments including 0.0, 0.84, 1.68, and 3.36 kg ai/ha imazapyr. Plot size was 6 m x 6 m with 5 replications in a randomized complete block design. Treatments were applied using a CO2 backpack sprayer with 11002 flat fan nozzles calibrated to deliver 187 L/ha. Both the overburden and sand areas were sprayed on November 19, 2002, while the clay settling area was sprayed December 12, 2002. In each of these three soil types, native species recolonization was observed in January 2004 (approximately 2 years after treatment) among the 3 imazapyr rates applied. All data were subjected to analysis of variance to test for main effects and interactions, and means separated using Fishers LSD procedure at the 0.05 level. Results and Discussion Long Term Cogongrass Control Table 4.1 shows percent cogongrass control in each of the previously sprayed areas in Polk County, Florida. Since these observations were made in January 2004, this table represents observations taken 4, 39, and 48 months after treatment (MAT) from separate sites. In the area sprayed in 2003, there was a significant difference between glyphosate and imazapyr plots (62 and 96% cogongrass control, respectively). There was also significant difference in the areas sprayed in 2001, 36 MAT (37% control in glyphosate plots and 88% control in imazapyr plots). These data show that up to 36 MAT, areas treated with 0.84 kg ai/ha imazapyr continue to provide statistically greater control of cogongrass than those treated with 3.36 kg ai/ha glyphosate. As time progressed to 48 MAT, there was no statistical difference between treatments. This continued control of cogongrass in imazapyr areas does not imply that imazapyr provides increased control as time progresses. The data might reflect differences in consistency with glyphosate control as seen in the difference in control with glyphosate between 2001 and 2000.

PAGE 81

68 Also, the data possibly suggest that initial higher control of cogongrass with imazapyr compared to glyphosate possibly allowed for other species to enter the area and compete with the cogongrass as regrowth occurred. Thirty nine MAT, there was no significant difference between herbicides in overall cogongrass control or the density of the 3 most commonly observed native speciesdogfennel (Eupatorium capillifolium), broomsedge (Andropogon virginicus), and saltbush (Baccharis halimifolia), as shown in Table 4.2. Rhizome Distribution Both glyphosate and imazapyr plots had approximately half of all samples classified as category 1no cogongrass within 0.6 meters, (52 and 56%, respectively) as shown in Table 4.3. Of these samples, only an average of 1.5% contained rhizomes, with low average weights (0.19g and 0.08g in glyphosate and imazapyr treatments.) Both herbicide treatments contained an average of 38% category 2 samplescogongrass within 0.6 meters, with approximately half of these samples containing rhizomes with average weights of 0.9g and 0.38g, respectively (Table 4.4). Only 9 and 6% of glyphosate and imazapyr samples were classified as category 3cogongrass present within core samples (Table 4.5). Of these samples, 100% contained rhizomes with average weights of 2.2g and 2.0g, respectively. These data help to support the hypothesis that the continued growth and spread of cogongrass after treatment in 2000 was due to patches remaining from initial control rather than regrowth from dormant rhizomes. This is because rhizomes were predominately associated with foliar patches. Native Species Recolonization Vegetation percent cover at the two of the three soil types in Polk County sprayed with imazapyr in 2002 was recorded. The third soil type was the clay settling pond area,

PAGE 82

69 but no data could be reported due to a fire that moved through the area in the fall of 2003. Due to the fire, all treatments in the clay area had cogongrass coverage averaging 100%. Data for the sand tailing area and the overburden area are shown in Tables 4.6 and 4.7. At the sand area in Polk County (Table 4.6), the most common species present was the non-native P. notatum, which was present prior to treatment in 2002, followed by the windblown species H. subaxillaris. There was no significant difference in percent cover for either species among varying imazapyr rates. Rhynchelytrum repens, Passiflora incarnata, Conyza canadensis, and cogongrass were also present, but with no statistical difference among imazapyr rates, including the untreated plots. Since cogongrass was still present in all imazapyr treated areas, it is not known if it spread from dormant rhizomes in the plot or rhizome invasion from adjacent untreated areas. In the overburden area, similar differences in imazapyr rates among all species is shown in Table 4.7. The most common species was again the non-native P. notatum, followed by R. repens, E. capillifolium, and Euthamia caroliniana, three species that spread by windblown seeds. Leguminous species such as Indigofera hirsuta, Crotalaria pallida, and Chamaecrista fasciculata were also present within the overburden plots, although at lower coverage. In related studies, legumes have shown tolerance in areas treated with imazapyr and show an ability to suppress cogongrass due to competitiveness (Akobundu et al. 2000; Gaffney 1996). A. virginicus, another wind-blown native species, was present in the check plots where no imazapyr was sprayed, yet only at minimal coverage. Overall, results from these studies do not suggest there were significant long-term effects on native plant recruitment due to imazapyr treatment. After 2 years, there was no

PAGE 83

70 significant difference in native species growth in two soil types for all rates of imazapyr. These data are helpful in understanding how a more effective revegetation strategy could be developed as part of an overall integrated cogongrass management system.

PAGE 84

71 Table 4.1. Cogongrass control over a 4-year period. Visual ratings taken in January 2004 in Polk County. 2003 2001 2000 kg ai/ha ----------------------% cogongrass control-------------------glyphosate 3.36 62 37 67 imazapyr 0.84 96 88 81 LSD 0.05 25 15 NS Table 4.2. The effect of glyphosate and imazapyr on native species 39 months after application in Polk County (area sprayed in Fall 2000). Eupatorium capillifolium Andropogon virginicus Baccharis halimifolia kg ai/ha ------------------------------% cover-----------------------------glyphosate 3.36 88 8 42 imazapyr 0.84 66 16 33 LSD 0.05 NS NS NS Table 4.3. Category 1 soil samplesno cogongrass within 0.6 meters of core samples. Rhizome data taken 39 months after herbicide application in Polk County. Category 1 no cogongrass within 0.6 meters kg ai/ha % of all samples % of samples with rhizomes average rhizome dry wt.(g) glyphosate 3.36 52 2 0.19 imazapyr 0.84 56 1 0.08 LSD0.05 NS NS NS

PAGE 85

72 Table 4.4. Category 2 soil samplescogongrass within 0.6 meters of core samples. Rhizome data taken 39 months after herbicide application in Polk County. Category 2 cogongrass within 0.6 meters kg ai/ha % of all samples % of samples with rhizomes average rhizome dry wt.(g) glyphosate 3.36 39 45 0.9 imazapyr 0.84 38 49 0.38 LSD0.05 NS NS NS Table 4.5. Category 3 soil samplescogongrass present within core samples. Rhizome data taken 39 months after herbicide application in Polk County. Category 3 cogongrass present kg ai/ha % of all samples % of samples with rhizomes average rhizome dry wt.(g) glyphosate 3.36 9 100 2.2 imazapyr 0.84 6 100 2.0 LSD0.05 NS NS NS

PAGE 86

Table 4.6. Natural presence of species on sand soil type burned and treated with imazapyr (Arsenal) in the fall of 2002 at Tenoroc WMA. Visual evaluations of percent cover were taken in fall of 2004 (24 months after treatment). 73 Rhynchelytrum repens Paspalum notatum Heterotheca subaxillaris Passiflora incarnata Conyza canadensis cogongrass imazapyr rate (kg ai/ha) ------------------------------------------------% cover----------------------------------------------0.0 30 70 40 23 10 50 0.84 30 39 33 -30 20 1.68 27 65 26 20 30 25 3.36 12 32 49 5 15 15 LSD 0.05 NS NS NS NS NS NS

PAGE 87

74 Table 4.7. Natural presence of species on overburden soil type burned and treated with imazapyr (Arsenal) in the fall of 2002 at Tenoroc WMA. Visual evaluations of percent cover were taken in fall of 2004 (24 months after treatment). 1Including Indigofera hirsuta, Crotalaria pallida, and Chamaecrista fasciculata. Rhynchelytrum repens Eupatorium capillifolium Euthamia caroliniana Paspalum notatum legume spp.1 Andropogon virginicus imazapyr rate (kg ai/ha) ----------------------------------------------% cover---------------------------------------------0.0 35 60 15 57 5 35 0.84 33 10 51 53 7 -1.68 44 8 15 60 11 -3.36 45 5 10 53 20 -LSD 0.05 NS NS NS NS NS NS

PAGE 88

CHAPTER 5 CONCLUSIONS Cogongrass [Imperata cylindrica (L.) Beauv.] is a highly invasive grass species found throughout much of the tropical and sub-tropical regions of the world, infesting over 500 million hectares worldwide (Holm et al. 1977). Cogongrass can usually be found in predominately non-agricultural settings in the United States, and spreads over vast areas where vegetation is marginally supported, suppressing and displacing many native plants (Bryson and Carter 1993). Cogongrass tolerates a wide range of soil conditions but appears to grow best in soils with acidic pH, low fertility, and low organic matter. This aggressive weed is able to spread and persist through several survival strategies including an extensive rhizome system, adaptation to poor soils, drought tolerance, prolific wind disseminated seed production, fire adaptability, and high genetic plasticity (Holm et al. 1977; Dozier et al. 1998). Current control methods for cogongrass rely heavily on chemical treatments which provide limited long-term control due to the presence of multiple cogongrass rhizomes, which can comprise over 2/3 the total plant biomass. Research to date has indicated imazapyr at 1.12 kg ai/ha applied late summer/early fall provides control for as long as 18 months (Dozier et al. 1998). Burning prior to herbicide application helps to remove dead biomass and promote new shoot growth, allowing for more effective control. Unfortunately, cogongrass will re-form a monotypic stand within 1-2 years after this time if additional treatments are not imposed (Dozier et al. 1998). 75

PAGE 89

76 Imazapyr provides good control of cogongrass but has limited utility due to the long residual effects of this compound, which could hinder revegetation strategies. An important step in the further suppression of cogongrass is to establish a native plant cover into these sprayed areas as soon as the residual herbicide levels in the soil become tolerable to the plant. Plant response to imazapyr in soil is useful information in determining which species would perform best in a plantback scenario. These studies showed that both Eucalyptus species (E. grandis and E. amplifolia), Mimosa strigillosa, Aristida beyrichiana, and Pityopsis graminifolia show low mortality response to imazapyr in soil. However, E. amplifolia and E. grandis both show higher injury response than many other species to imazapyr in this study. The data show that these species might be able to outgrow the imazapyr injury after some period of time. Even though a plant might show initial injury symptoms, the overall ability of that plant to recover is a very important quality to look for in a potential revegetation species. Another concern with revegetation is the amount of imazapyr residues in different soils. Soil type has an important influence on the residual amount of herbicide due to the soil structure and content of clay and organic matter. Central Florida is home to many reclaimed mining sites which have a diverse collection of soil types, with overburden, sand tailings and phosphatic clay pits being the most prominent. These three soil types involved in phosphate mining processes are highly diverse in nature, yet they are all susceptible to cogongrass and other non-native weed invasions. This is due to the disturbance of the areas during the mining process and the associated harsh conditions to which plants are subjected. Because of this diversity of soils in Florida, as well as much of the U.S., an understanding of herbicide persistence as a function of soil type is

PAGE 90

77 important in predicting the best time for revegetation. Samples of these soils were taken after a certain amount of time after herbicide application and information on residue amounts was generated using corn bioassay techniques. These residual data were used to estimate the best time for revegetation to occur based on the imazapyr residues reaching a tolerable level in soil. In all three areas sprayed, detected residues were substantially lower than expected, which could be due to a dense vegetative cover found in the areas during herbicide application that might have prevented imazapyr from fully reaching the soil surface. Vegetative cover, either as dead biomass or thatch, is common in areas chemically treated for cogongrass. This might be beneficial in revegetation planning since soil imazapyr residues might be lower than expected due to this foliar uptake. Six species can be planted immediately after an imazapyr application of 0.84 kg ai/ha and expect to show no less than 60% mortality 10 weeks after planting. These species (E. amplifolia, mimosa, longleaf pine, E. grandis, silkgrass, and wiregrass) could potentially suppress cogongrass regrowth if they are established at this critical time. Based on the wait time in relation to injury data, E. grandis and switchgrass are good candidates for use in revegetation planning. Several additional species, including E. amplifolia, mimosa, longleaf pine, silkgrass, and wiregrass, would be good choices in a plantback scenario if percent mortality is a more desirable quality than injury. These estimated plantback dates after initial imazapyr application will be helpful in determining optimum timing of a revegetation project. Knowing what species will best tolerate imazapyr and how long to wait before planting can reduce the gap of time between initial cogongrass control and its reinvasion of an area.

PAGE 91

78 These data regarding the most tolerable plants to be used as revegetation species is valuable research, but it is important to consider the costs involved with transplanting, as well as the overall desirability of the species by landowners. Economical aspects should be studied in future research and be taken into consideration to ultimately identify the benefits of this type of revegetation planning. As earlier stated, even in areas where management has been successful, cogongrass re-infestation will often occur. Because of this, studying reinfestation of dormant cogongrass rhizomes is also an important aspect of overall integrated control. In addition, monitoring natural recruitment of native species in areas previously treated with these herbicides will help to understand which plant species are more competitive with cogongrass. Studies conducted show that cogongrass is continually suppressed over a period of time after treatment with imazapyr. Glyphosate, also used on cogongrass, provided consistently less control. This continued control of cogongrass in imazapyr areas does not imply that imazapyr provides increased control as time progresses. Instead, the data suggests that initial higher control of cogongrass with imazapyr compared to glyphosate possibly allowed for other species to enter the area and compete with the cogongrass as regrowth occurred. Studying rhizome presence in areas previously treated for cogongrass control gave data which help support the hypothesis that the continued growth and spread of cogongrass after a treatment in 2000 is due to patches remaining from initial control rather than regrowth from dormant rhizomes. This is because rhizomes were only found where there were foliar patches. Overall, results of studies related to natural recruitment in different soil types suggest that there are no significant long-term effects on native

PAGE 92

79 plant recruitment due to imazapyr residues in the soil. After 2 years, there is no significant difference in native species growth in two soil types for all levels of imazapyr. These data are helpful in understanding how native species react to a post-imazapyr treated area for further cogongrass suppression.

PAGE 93

APPENDIX STANDARD CURVES FOR CORN ROOT BIOASSAY imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 root length (cm) 0246810121416 y=2.3+12.3*exp (-26.7*x) R2= 0.87 Figure A-1. The effect of imazapyr concentration on corn root length in a sand tailings soil type in Polk County, FL. Regression analysis used to determine unknown imazapyr concentrations in sand tailings soil 0 Months After Treatment (MAT). Values shown in Table 3.1. 80

PAGE 94

81 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 root length (cm) 024681012141618 y=1.4+16.4*exp(-36.7*x) R2=0.97 Figure A-2. The effect of imazapyr concentration on corn root length in a sand tailings soil type in Polk County, FL. Regression analysis used to determine unknown imazapyr concentrations in sand tailings soil 1 Month After Treatment (MAT). Values shown in Table 3.1.

PAGE 95

82 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 root length (cm) 02468101214 y=2.0+10.8*exp (-44.0*x) R2=0.97 Figure A-3. The effect of imazapyr concentration on corn root length in a sand tailings soil type in Polk County, FL. Regression analysis used to determine unknown imazapyr concentrations in sand tailings soil 3 Months After Treatment (MAT). Values shown in Table 3.1.

PAGE 96

83 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 root length (cm) 024681012141618 y=1.7+15.2*exp(-40.5*x) R2= 0.83 Figure A-4. The effect of imazapyr concentration on corn root length in a clay soil type in Polk County, FL. Regression analysis used to determine unknown imazapyr concentrations in clay soil 0 Months After Treatment (MAT). Values shown in Table 3.2.

PAGE 97

84 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 root length (cm) 02468101214161820 y=1.4+16.4*exp(-36.7*x) R2=0.97 Figure A-5. The effect of imazapyr concentration on corn root length in a clay soil type in Polk County, FL. Regression analysis used to determine unknown imazapyr concentrations in clay soil 1 Month After Treatment (MAT). Values shown in Table 3.2.

PAGE 98

85 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 root length (cm) 0246810121416 y=1.5+12.1*exp(-23.3*x) R2=0.90 Figure A-6. The effect of imazapyr concentration on corn root length in a clay soil type in Polk County, FL. Regression analysis used to determine unknown imazapyr concentrations in clay soil 3 Months After Treatment (MAT). Values shown in Table 3.2.

PAGE 99

86 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 root length (cm) 0246810121416 y =2.0+12.6*exp(-28.3*x) R2= 0.95 Figure A-7. The effect of imazapyr concentration on corn root length in an overburden soil type in Polk County, FL. Regression analysis used to determine unknown imazapyr concentrations in overburden soil 0 Months After Treatment (MAT). Values shown in Table 3.3.

PAGE 100

87 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 root length (cm) 0246810121416 y =1.6+11.8*exp(-33.0*x) R2=0.94 Figure A-8. The effect of imazapyr concentration on corn root length in an overburden soil type in Polk County, FL. Regression analysis used to determine unknown imazapyr concentrations in overburden soil 1 Month After Treatment (MAT). Values shown in Table 3.3.

PAGE 101

88 imazapyr concentration (kg ai/ha) 0.00.20.40.60.81.01.2 root length (cm) 0246810121416 y =0.9+12.7*exp(-32.7*x) R2=0.93 Figure A-9. The effect of imazapyr concentration on corn root length in an overburden soil type in Polk County, FL. Regression analysis used to determine unknown imazapyr concentrations in overburden soil 3 Months After Treatment (MAT). Values shown in Table 3.3.

PAGE 102

89 days after treatment (DAT) 020406080 100 imazapyr concentraton (kg ai/ha) 0.000.020.040.060.080.10 y =0.08*exp(-0.05*x) R2=0.99 Figure A-10. Imazapyr concentration as a function of days after treatment (DAT) in a clay soil type in Polk County, FL. Regression analysis used to determine imazapyr concentrations over time after initial application of 0.84 kg ai/ha. Values shown in Table 3.4.

PAGE 103

90 days after treatment (DAT) 020406080 100 imazapyr concentration (kg ai/ha) 0.000.020.040.060.080.100.12 y =0.10*exp(-0.06*x) R2=0.97 Figure A-11. Imazapyr concentration as a function of days after treatment (DAT) in an overburden soil type in Polk County, FL. Regression analysis used to determine imazapyr concentrations over time after initial application of 0.84 kg ai/ha. Values shown in Table 3.5.

PAGE 104

LIST OF REFERENCES Akobundu, I.O., U.E. Udensi, and D. Chikoye. 2000. Velvetbean (Munuca spp) suppresses speargrass (Imperata cylindrica (L.) Raeuschel) and increases maize yield. Int. J. Pest. Manage. 46:103-108. Anonymous. 2002. Herbicide Handbook. Lawrence, KS: Weed Science Society of America. Pp. 251-253. Barnett, J.W., Jr., J.D. Byrd, Jr., and D.B. Mask. 2000. Efficacy of herbicides on cogongrass (Imperata cylindrica). Proc. South. Weed Sci. Soc. 53:227. Brook, R.M. 1989. Review of literature on Imperata cylindrica (L.) Raeuschel with particular reference to South East Asia. Trop. Pest Manage. 35:12-25. Bryson, C.T. and R. Carter. 1993. Cogongrass, Imperata cylindrica, in the United States. Weed Technol. 7:1005-1009. Dickens, R. 1974. Cogongrass in Alabama after sixty years. Weed Sci. 22:177-179. Dickens, R. and G.A. Buchanan. 1975. Control of cogongrass with herbicides. Weed Sci. 23:194-197. Dickens, R. and G.M. Moore. 1974. Effects of light, temperature, KNO3, and storage on germination of cogongrass. Agron. J. 66:187-188. Dozier, H., J.F. Gaffney, S.K. McDonald, E.R.R.L. Johnson, and D.G. Shilling. 1998. Cogongrass in the United States: history, ecology, impacts, and management. Weed Technol. 12(4):737-743. English, R. 1998. The regulation of axillary bud development in the rhizomes of cogongrass [Imperata cylindrica (L.) Beauv.]. M.S. dissertation, University of Florida, Gainesville, FL, USA. 123 p. Gaffney, J.F. 1996. Ecophysiological and technical factors influencing the management of cogongrass (Imperata cylindrica). Ph.D. dissertation, University of Florida, Gainesville, FL, USA. 111 p. Garrity, D.P., M. Soekardi, M. Van Noordwijk, R. De La Cruz, P. S. Pathak, H.P.M. Gunasena, N. Van So, G. Huijun, and N.M. Majid. 1996. The Imperata grasslands of tropical Asia: area, distribution, and typology. Agrofor. Syst. 36(1-3): 3-29. 91

PAGE 105

92 Hartley, C.W.S. 1949. An experiment on mechanical methods on Lalan eradication. Malay Agric. J. 32:236-252. Holm, L.G., D.L. Pucknett, J.B. Pancho, and J.P. Herberger. 1977. The Worlds Worst Weeds: Distribution and Biology. Univ. Press of Hawaii: Honolulu, HI. 609 p. Hubbard, C.E. 1944. Imperata cylindrica. Taxonomy, distribution, economic significance, and control. Imp. Agric. Bur. Joint Publ. No. 7, Imperial Bureau Pastures and Forage Crops, Aberstwyth, Wales. 53 p. Johnson, E.R.R.L., J.F. Gaffney, and D.G. Shilling. 1999. The influence of discing on the efficacy of imazapyr for cogongrass [Imperata cylindrica (L.) Beauv.] control. Proc., South. Weed Sci. Soc. 52:165. Kluson, R.A., S.G. Richardson, D.B. Shibles, and D.B. Corley. 2000. Responses of two native and two non-native grasses to imazapic herbicide on phosphate mined lands in Florida. In Proc. 17th Annual Meeting of the American Society for Surface Mining and Reclamation, June 11-15, 2000, Tampa, FL. Pp. 49-57. Lauer, D.K., H.E. Quicke, and P.J. Minogue. 2002. Early season site preparation with different imazapyr formulations. Proc. South. Weed Sci. Soc. 55:83-88. Lee, S.A. 1977. Germination, rhizome survival, and control of Imperata cylindrica (L.) Beauv. on peat. MARDI Res. Bull., Malaysia. 5:1-9. MacDonald, G.E. 2004. Cogongrass (Imperata cylindrica) biology, ecology and management. Crit. Rev. Plant Sci. 23(5):367-380. MacDonald, G.E., E.R.R.L. Johnson, D.G. Shilling, D.L. Miller, and B.J. Brecke. 2002. The use of imazapyr and imazapic for cogongrass [Imperata cylindrica (L.) Beauv.] control. Proc. South. Weed Sci. Soc. 55:110. Mangels, G. 1991. Behavior of the imidazolinone herbicides in the aquatic environment. In D.L. Shaner and S.L. OConnor, eds. The Imidazolinone Herbicides. CRC Press: Boca Raton, FL. Pp 183-190. Marchbanks, P.R., J.B. Byrd, Jr., J.W. Barnett, Jr., D.B. Mask, and K.D. Burnell. 2002. Comparison of Burch Wet Blade and conventional boom applications for control of cogongrass (Imperata cylindrica). Proc. South. Weed Sci. Soc. 55:66-67. Marion, W. R. 1986. Phosphate mining: regulations, reclamation, and revegetation. Florida Institute of Phosphate Research. Bartow, FL. 72 p. McBride, M.B. 1994. Environmental Chemistry of Soils. New York, NY: Oxford University Press. 406 p.

PAGE 106

93 Miller, D., G.E. MacDonald, D. Shilling, and B. Brecke. 2002. Integrated management of invasive weeds as a component of native plant restoration. Final Report. Florida Institute of Phosphate Research. Bartow, FL. 72 p. Miller, J.H. 2000. Refining rates and treatment sequences for cogongrass (Imperata cylindrica) control with imazapyr and glyphosate. Proc. South. Weed Sci. Soc. 53:131-132. Norcini, J.G., T.N. Chakravarty, R.S. Kalmbacher, and W. Chen. 2003. Micropropagation of wiregrass and creeping bluestem, and propagation of gopher apple. Final Report. Florida Institute of Phosphate Research. Bartow, FL. 144 p. OBryan, K.A, B.J. Brecke, D.G. Shilling, and D.L. Colvin. 1994. Imazaquin dissipation in soil and its effect on sicklepod (Cassia obtusifolia L.) interference with soybean (Glycine max (L.) Merr.). Weed Technol. 8:203-206. Patterson, D.T., E.E. Terrell, and R. Dickens. 1979. Cogongrass in Mississippi. Miss. Agric. For. Exp. Stn. Res. Rep. 46(6):1-3. Pfaff, S., C. Maura, Jr., and M.A. Gonter. 2002. Development of seed sources and establishment methods for native upland reclamation. Final Report. Florida Institute of Phosphate Research. Bartow, FL. 73 p. Prine, G. and E.C. French. 1999. New forage, grain, and energy crops for Humid Lower South, US. In J. Janick, ed. Perspectives on New Crops and New Uses. ASHS Press: Alexandria, VA. Pp. 60. Richardson, S.G., N. Bissett, C. Knott, and K. Himel. 2003. Weed control and upland native plant establishment on phosphate mined lands in Florida. Final Report. Florida Institute of Phosphate Research. Bartow, FL. 12 p. Rockwood, D.L. 1996. Eucalyptuspulpwood, mulch or energywood? Univ. of Fla. Coop. Ext. Serv., circular 1194. Rockwood, D.L., S.M. Pisano, and W.V. McConnell. 1996. Superior cottonwood and Eucalyptus clones for biomass production in wastewater bioremediation systems. Proc. Bioenergy 96, 7th National Bioenergy Conference, Sept 15-20, 1996, Nashville, TN. Pp 254-261. Sajise, P.E. 1976. Evaluation of cogon [Imperata cylindrica (L.) Beauv.] as a serial stage in Philippine vegetational succession. 1. The cogonal serial stage and plant succession. 2. Autecological studies on cogon. Weed Abst. 1339:3040-3041. Saxena, K.G. and P.S. Ramakrishnan. 1983. Growth and allocation strategies of some perennial weeds of slash and burn agriculture (jhum) in northeastern India. Can. J. Bot. 61:1300-1306.

PAGE 107

94 Schuler, J.L., D.J. Robison, and H.E. Quicke. 2004. Assessing the use of Chopper herbicide for establishing hardwood plantations on a cutover site. BASF Forestry Research Report 2004-03. 13 p. Segal, D.S., V.D. Nair, D.A. Graetz, K.M. Portier, N.J. Bissett, and R.A. Garren. 2001. Post-mine reclamation of native upland communities. Final Report. Florida Institute of Phosphate Research. Bartow, FL. 107 p. Segrest, S.A., D.L. Rockwood, J.A. Stricker, A.E.S. Green, and W.H. Smith. 1998. Biomass co-firing with coal at Lakeland, FL, USA, Utilities. Proc. 10th European Biomass for Energy and Industry Conf., June 8, 1998, Wurzburg, Germany. Pp. 1472. Shaner, D. 1991. Physical effects of the imidazolinone herbicides. In D.L. Shaner and S.L. OConnor, eds. The Imidazolinone Herbicides. CRC Press: Boca Raton, FL. Pp 129-138. Shilling, D.G., T.A. Bewick, J.F. Gaffney, S.K. McDonald, C.A. Chase, and E.R.R.L. Johnson. 1997. Ecology, physiology, and management of cogongrass (Imperata cylindrica). Final Report. Florida Institute of Phosphate Research. Bartow, FL. 128 p. Soerjani, M. 1970. Alang-alang Imperata cylindrica (L.) Beauv., pattern of growth as related to its problem of control. Biol. Trop. Bull. 1:88-96. Stricker, J.A. 2000. High value cash crop potential of reclaimed phosphatic clay soil. Proc. Annual Meeting Amer. Soc. Surface Mining and Reclamation, June 11-15, Tampa, FL. 11 p. Terry, P.J., G. Adjers, I.O. Akobundu, A.U. Anoka, M.E. Drilling, S. Tjitrosemito, and M. Utomo. 1997. Herbicides and mechanical control of Imperata cylindrica as a first step in grassland rehabilitation. Agrofor. Syst. 36:151-179. Tominaga, T. 2003. Growth of seedlings and plants from rhizome pieces of cogongrass [Imperata cylindrica (L.) Beauv.] Weed Biol. Manage. 3:193-195. Willard, T.R. and D.G. Shilling. 1990. The influence of growth stage on competition between Paspalum notatum and Imperata cylindrica. Trop. Grass. 24:81-86.

PAGE 108

BIOGRAPHICAL SKETCH Born on January 28, 1979, Melissa Carole Barron is the only child of Bryant and Carol Barron of Liberty, Mississippi. Born and raised in the small town of Liberty, Melissa was surrounded by nature and wildlife, which helped her to develop a strong interest in environmental sciences. After finishing at Franklin High School with honors in 1997, she went on to receive a Bachelor of Science degree in soil science from Mississippi State University in 2001. After completing her Master of Science degree in agronomy at the University of Florida in 2005, Melissa plans to pursue a career in environmental consulting. 95


xml version 1.0 encoding UTF-8
REPORT xmlns http:www.fcla.edudlsmddaitss xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.fcla.edudlsmddaitssdaitssReport.xsd
INGEST IEID E20101130_AAAABW INGEST_TIME 2010-11-30T13:48:23Z PACKAGE UFE0010801_00001
AGREEMENT_INFO ACCOUNT UF PROJECT UFDC
FILES
FILE SIZE 6010 DFID F20101130_AABISH ORIGIN DEPOSITOR PATH barron_m_Page_006thm.jpg GLOBAL false PRESERVATION BIT MESSAGE_DIGEST ALGORITHM MD5
52b9260afd37305febea222e81a0f777
SHA-1
baedbf63d3a7555a2993c986d0289db707f0d182
691 F20101130_AABIRS barron_m_Page_102.txt
2507063b91634b06e8ebd96b09197234
60d83dc71f94e0a47ea44c8363c473aa84ed99ca
12418 F20101130_AABISI barron_m_Page_007.QC.jpg
98a586ffa5e1636f51f3f0d06eb88433
cfe192eb56ead4d78e3169cb951237b35457266f
752 F20101130_AABIRT barron_m_Page_103.txt
be4257e02337d29318548bffce04f0b8
bb28c4187e7d5fcfecc666b7508e92014b05de5d
3443 F20101130_AABISJ barron_m_Page_007thm.jpg
95506802745236a89ccb9b7faadcfd4a
14603597a2f7116f5c445b39e2b46c26b6d6291b
2033 F20101130_AABIRU barron_m_Page_104.txt
ac0fa4250495b4ea1e827ebd19624a6c
6e0ef1729c064d9d9ebe5648e5e4ab2d9de95e07
6181 F20101130_AABISK barron_m_Page_008thm.jpg
a66db00fb812a88d7d19b585ca97240a
bfbb65f3257b1443477f35388bc7ac7a87be5c85
2472 F20101130_AABIRV barron_m_Page_105.txt
ca14f65c89a3f452a541156e65dfcb6a
6b1dcd1bee63a8772d5d67a09663d7d37606c4f5
30264 F20101130_AABISL barron_m_Page_009.QC.jpg
ce1aad82824b3860417fb30d371b5e6e
3c275b0ae9af376984a427beb8cd2be200baa607
2582 F20101130_AABIRW barron_m_Page_106.txt
d74c19b64191c7743ed596ec178823f2
6c6176924b2ac56cdeadf3312c76451cafc57f4a
2102 F20101130_AABIRX barron_m_Page_107.txt
9d428ee903e78a2fee86237177dcb140
2f240efc4f8e42a18fb284e220c69fa696b1de50
24276 F20101130_AABITA barron_m_Page_017.QC.jpg
0a4a238fc8f1a1aa4c869295346154ec
d2129c7f13d558ec3b55186f75b5cf4d8f1003d2
7417 F20101130_AABISM barron_m_Page_009thm.jpg
4aa69f6e189ad7db65f4ec269dc0f83e
008d0e9f02675555ac7e71c6605d8c09dee1062b
7746 F20101130_AABIRY barron_m_Page_001.QC.jpg
4a4674a50a94279772ea530b4ee1daab
8096e515fcb0208b7130783902cce76caae21054
6562 F20101130_AABITB barron_m_Page_017thm.jpg
fb39f66a05a57bc3721a8d727e2c6406
d29ed2e42581cbd17f78dc1dba82dacb6b6d98d5
27820 F20101130_AABISN barron_m_Page_010.QC.jpg
59c554ccec4bb89e44c903000447b54a
ed88f04111884412331ed8b932faf1f1edce4eb6
3383 F20101130_AABIRZ barron_m_Page_002.QC.jpg
6fbb6081e103dddaaceea37dd8f29f03
9b9d2c55e265a3974bd77eaefd33f26445193ecc
24054 F20101130_AABITC barron_m_Page_018.QC.jpg
5e79232c9294172de3859000236c6b58
c848a8f83ed9c4b77db688203e913e5dc7de86b3
7185 F20101130_AABISO barron_m_Page_010thm.jpg
d3d7b91511dc2441d9c2b09e498a4048
02b899866d5a049d35d1aa43bba93ba853612cee
6576 F20101130_AABITD barron_m_Page_018thm.jpg
d3e927afea32e1e5aa8c008be4c14473
b7cd756de732faab103e73ae52e8d808d05ae638
8283 F20101130_AABISP barron_m_Page_011.QC.jpg
5cc6f6c60089190dd3d3898cf67f9ba0
41528a3f45c201f8dc251e6aeb0d39ee3720b1a6
23022 F20101130_AABITE barron_m_Page_019.QC.jpg
7c55cde205846256818286b190d46000
434d71cc7d56c7565122f3f0362e772cd34f2727
2523 F20101130_AABISQ barron_m_Page_011thm.jpg
a811044ab6759e216aaad8cb480f6284
70a2570a2be1e1fcf86093572ce27d4fb54a0b19
6244 F20101130_AABITF barron_m_Page_019thm.jpg
74f2d94ed0171957ccd203a6ad6412aa
e648123b0b5a1f25761da9a34877fc82755c6d17
19057 F20101130_AABISR barron_m_Page_012.QC.jpg
4fa221e5be014251f915573755abb0ca
2027f7ca1a76cb924de8c2d3687824a87abf54c1
6158 F20101130_AABITG barron_m_Page_020thm.jpg
0fb1c1f42a9664736917cf46e7aa3e77
c1319572f6f625379759c93ff7b75aa212fc9211
22772 F20101130_AABISS barron_m_Page_013.QC.jpg
6025ad32b013cf33bcde1b1cc84ec838
b642d7c02d39d1876795b3b221c0c79d818df7a0
23680 F20101130_AABITH barron_m_Page_021.QC.jpg
b0a3f1ea22c986a955e37fa6949ccd48
9409d40180d1b972d325740f37d100ec70110c24
6307 F20101130_AABIST barron_m_Page_013thm.jpg
73979c0a5f161bf5c21f2ef7d039c6d7
1ce25de683b9e00141aced5fe1fac36c87be40d0
6609 F20101130_AABITI barron_m_Page_021thm.jpg
705a2c614ea460f6bd84deb19397fc8a
68beb07f1239f4523f34e09f0c0bb00dda1ddbfb
20988 F20101130_AABISU barron_m_Page_014.QC.jpg
aaf586a49acb13ec294bd79d63c1471d
57d005be316e9a5888ca08ccfebbb5df4c3341cc
22994 F20101130_AABITJ barron_m_Page_022.QC.jpg
8fec8879fb48af596cade412877fbc38
ed4e6f8dc0a463d9ea5db99d82162b606981c28b
6045 F20101130_AABISV barron_m_Page_014thm.jpg
792a122206df803bc36addf20df1a32f
1e125a05bf2a5646264c2d468b1d03e394492372
6453 F20101130_AABITK barron_m_Page_022thm.jpg
c3ae10f59690897dfce747ec074c0b27
4ee2c6485ac003c9236991a47e9e2464eb2c6067
23797 F20101130_AABISW barron_m_Page_015.QC.jpg
cbe26562682a5bc0d22af979075d7220
b4577ea1df5afa88f47db2d45a3937d129357ac0
23615 F20101130_AABITL barron_m_Page_023.QC.jpg
e220ce49697bcd9433c95f9d0b50f4c5
2e71bd91a45516b178443237ec85057d35e3e273
6612 F20101130_AABISX barron_m_Page_015thm.jpg
8569e40bdf822afbd9f55d0338615277
27b335cdc376d7c6affb0919f5fb534037461237
6693 F20101130_AABIUA barron_m_Page_031thm.jpg
778cacdb8acbe241e89ce9188499d54b
ba11d5899e741b7bf942dcd8d6069000267e56e8
6468 F20101130_AABITM barron_m_Page_023thm.jpg
990ed1fa466ada806d7d738c0ad86aa7
7c575bb65c8f5f7b195cdf856ac039d0799ef971
24512 F20101130_AABISY barron_m_Page_016.QC.jpg
059763c530041d6668e928dd7d5786eb
8ebb20643387a89de81fbc086b5d1e843a9f3b78
23718 F20101130_AABIUB barron_m_Page_032.QC.jpg
b9ee5157d3641be6a099959dfb12f607
4224e8f4520b67d24d4358cf64d6da745af148bc
6625 F20101130_AABISZ barron_m_Page_016thm.jpg
dd35a3c5704b3d9f7518f9f849e6081b
302348f8103aeb26f939bb8b6f2f09a3ddcb1079
5188 F20101130_AABIUC barron_m_Page_033.QC.jpg
db7526cd6cdd58b4e1bdcb36185dc7b5
a57d2163254c41cdc3bd6d7f3529bb28f8bca81d
2575 F20101130_AABITN barron_m_Page_024thm.jpg
eaac6bfa9b389a6ce2d9d6bff4471e94
20816fd8e044a1009cf284cace2f3b49eec0791a
1793 F20101130_AABIUD barron_m_Page_033thm.jpg
126e0eab3e57f8aaaad6bbd7e364bbac
83db468bce37b7cff95315841d4e67e0e6b194c1
20945 F20101130_AABITO barron_m_Page_025.QC.jpg
1699ba119ca75facabe6d600b3248349
7e5828d80469beb0fe52db9456e628e50c0bdff1
8299 F20101130_AABIUE barron_m_Page_034.QC.jpg
125aa27b6b77ad74fdbf16ca4cdf75b5
a17287f5eb861717e9740075a04a3c8d1468bf97
5958 F20101130_AABITP barron_m_Page_025thm.jpg
35d8088a409ae5388179eec9f7c8237c
d4fd5694a472300d27f81d9b79c6f9d57ca74fbb
2981 F20101130_AABIUF barron_m_Page_034thm.jpg
249e7ce3d7fbe9942a33ad74b5f32f83
0e9c186f712fda7cbf86fe54b3261b1aa7f26090
21795 F20101130_AABITQ barron_m_Page_026.QC.jpg
fe73fd96dcc4af417bd00ffbf71763d3
767d88b263fe7e92d8003531ca3ec2d808ccc4e5
3035 F20101130_AABIUG barron_m_Page_035thm.jpg
5db534b6c40f23ae4ff7f7f88e21064b
8ce0121a1b654bdad2be323f7dd88f32d8c90161
6132 F20101130_AABITR barron_m_Page_026thm.jpg
506dc3d1988ca6865c2d0e3537405176
a9ca632cff312b81412933eb0ae102ebb3b3279e
8501 F20101130_AABIUH barron_m_Page_036.QC.jpg
7793b3ecc267de11aac64c3e44763ea7
763d1bbf43a25d3aaec954de9d3c98e77064e06e
23714 F20101130_AABITS barron_m_Page_027.QC.jpg
2a8384a98c085d3584f5b3c2b7b32086
0134637ef87c16514c476880ae40e5a9bf3e0152
2954 F20101130_AABIUI barron_m_Page_036thm.jpg
229eb0e82c845e1fe6c1fcd9973bfbe8
3619844fd4877c5ad7b00df8dea07f6e7f3b4d1f
6460 F20101130_AABITT barron_m_Page_027thm.jpg
3122c31b14dbe30df02dd900f02cffde
7bc6a1dd33948d7f7a346aa8f56a762fb3998080
8368 F20101130_AABIUJ barron_m_Page_038.QC.jpg
ef7615974eb12aac1f6586a4a6d99f78
38be1a4d9cb542a901f094bf040f72e418774181
21731 F20101130_AABITU barron_m_Page_028.QC.jpg
2e3af593b8b7ff5278bbbf33595b891c
2c53efc7bf5589f5e2dfd0b23cdb709e1cb140d1
2856 F20101130_AABIUK barron_m_Page_038thm.jpg
e823c15fd0f701af45f81fa36fafbb2f
a7edfed2ef963c65f1370f237c85fb138eb67510
6360 F20101130_AABITV barron_m_Page_028thm.jpg
868a815567015618c049c20fefc2eacd
c908ff7e0e27fd8907ab8b76bb2cf49d21c78775
8591 F20101130_AABIUL barron_m_Page_039.QC.jpg
2f56158b32e1191dc17fe5dbe101e939
ccc2f240e694571d072a58c51086272eff69b514
22695 F20101130_AABITW barron_m_Page_029.QC.jpg
4480ab4793bccf2de20560c8b78edb85
0abadee9f5587ce263486ec480434a69ba9d1efc
8269 F20101130_AABIVA barron_m_Page_047.QC.jpg
9bd03bb06fa15d67366bb1087967b963
3dd8f7a4e5f9126a9c7996db8735a69e50a0e245
F20101130_AABIUM barron_m_Page_039thm.jpg
4a61a51f95f0b5af92660bc3a406b553
cfdbe8d3ce88aeada2778da717f29fe2ad071bad
6433 F20101130_AABITX barron_m_Page_029thm.jpg
298c4fe892561422c2a12ab28a07967e
d3cb3b388bc90459692e0904dafd8a7c96f5f2e0
2912 F20101130_AABIVB barron_m_Page_047thm.jpg
4aa2192ab386d427369f535e11464932
1f972e2b465d502f528e6bda01a280d0d20f5613
8221 F20101130_AABIUN barron_m_Page_040.QC.jpg
8904286e70555ecb8b6db6e523fd760b
9d7b19dfaf4e00a5dd9851120dc2cc902fa3fa30
6404 F20101130_AABITY barron_m_Page_030thm.jpg
7edfe8ef075c3cff0c10446804ec32b9
2cd1b480c1ee6bf4ed2492f8a1c58db7e065a9d4
24385 F20101130_AABITZ barron_m_Page_031.QC.jpg
5159d33c6a7085f98646543b0158f250
24734b4fc94672423d91e72df9ee71970ce801d2
8523 F20101130_AABIVC barron_m_Page_048.QC.jpg
71cec089c8ec409e64e4ed4ecde990d7
c8f1b5e47ff818b121317cdb6c8875bbccbabdd5
2899 F20101130_AABIUO barron_m_Page_040thm.jpg
096f136570b3ec9d232d5b414a04848e
bbaf1b82a7f318191467eb47bf6c57af667d2224
2939 F20101130_AABIVD barron_m_Page_048thm.jpg
6920109d782ffd343e5a19dc513b32c7
e0e1530e6b9c1915f7ca088b31c26e08a71455b2
9051 F20101130_AABIUP barron_m_Page_041.QC.jpg
d819866f765b192193095d0f96ecce6f
6e05021d3ba081e0de87d3b5fc90164d6d293258
8301 F20101130_AABIVE barron_m_Page_049.QC.jpg
88729c89e73720828c8a59cfcdc6f17f
cbe38e166d54ada7532f28730ade1331b3f22863
8311 F20101130_AABIUQ barron_m_Page_042.QC.jpg
d786d7feb1d1af75c10bd1264846eaa1
80485efca43e020dc760e5323033b6ce5e50a524
2941 F20101130_AABIVF barron_m_Page_049thm.jpg
e8e46fb9bd4507d5210d4d754a072e63
4a3f39b63ff98db348aeac343e44d2884a09ee5d
2998 F20101130_AABIUR barron_m_Page_042thm.jpg
3c1f39b605ec40351d3f381ab8a70e67
e521755749c0af5d9dbd7de9d59c1d0b3e8e2c76
8897 F20101130_AABIVG barron_m_Page_050.QC.jpg
6c6ac7e1643ab000604bfbb778b66c75
c73e6ed6e13349e945800466653f3fbedd3521af
8335 F20101130_AABIUS barron_m_Page_043.QC.jpg
d768ccd8a30f1376de1a68553de56a32
840a6fcfa0b98d90cc6ba0a63401fa746fe2ff07
3074 F20101130_AABIVH barron_m_Page_050thm.jpg
b07a9f23c2e8f868ef433bc142ad665c
4a3ec2bb5aba4f4437178ba62fb7b7458ac9ec8f
2908 F20101130_AABIUT barron_m_Page_043thm.jpg
c986d5b9c369b1f0c2d41334d83101b6
ec662e4b25b107f57e771727e39c47f7d8b26937
8429 F20101130_AABIVI barron_m_Page_051.QC.jpg
d3a6eb866be465d4dee1375ca9dbf331
6be25e6d80239ac23900b521fda7d842d8af1dd3
8483 F20101130_AABIUU barron_m_Page_044.QC.jpg
bbe34097c2eacec510f947ff934f3449
bbf417e4c416f47aa6653b48927519902be19910
3047 F20101130_AABIVJ barron_m_Page_051thm.jpg
e5c6719cd4c09446e1daee079b8d6bb9
5836f9d900ad4da70a2fd2fd660407964fc789f9
2961 F20101130_AABIUV barron_m_Page_044thm.jpg
fa5e1d19be76606227f8b17c69de9658
da932c9b1f531a2087c8c271154af2fe8eb40043
8566 F20101130_AABIVK barron_m_Page_052.QC.jpg
3c07d1ce2d24c41dcd6060b102e3a350
30a86e890cc7dad9461258e6fe6372758e176172
8252 F20101130_AABIUW barron_m_Page_045.QC.jpg
ec0b4cbcb7aa314cb14a52c2cc82fe71
0f39c18ff358cbbd5328ca88dc1e415a57208bff
8150 F20101130_AABIVL barron_m_Page_053.QC.jpg
5f7e70b43faa29c054db2de1ec268c88
aa2d4ba13bef3c095c5d777b98c9a82eee60a0e1
2813 F20101130_AABIUX barron_m_Page_045thm.jpg
9d007cc0b6261ea9b7f91fa06c678eb0
1dfc7dff1143afcea5a227d4b08e40605c691484
23966 F20101130_AABIWA barron_m_Page_062.QC.jpg
898d610c2bc98674ffa04329d438089b
c41275d9a7dc43478dcbf37d075925228ba4aec3
2943 F20101130_AABIVM barron_m_Page_053thm.jpg
02f5e84a0ec9bf16bdbc7035618d1873
d385be451bba737f5d1ac23fbe71bd0397e505d7
8222 F20101130_AABIUY barron_m_Page_046.QC.jpg
e8885bb54fa18ae4d0cc88f40a8b0c68
d20a863ed91fe8154afbb64c2e3438618397850f
6494 F20101130_AABIWB barron_m_Page_062thm.jpg
7fc3878599f057ce98974bcd8b600b60
3c07ef416904ae57e3cb70cf486be94a7bf86cf5
8486 F20101130_AABIVN barron_m_Page_054.QC.jpg
e85b41cb5ddf2a43ce64870dc5dda1e7
3b740ee8362be4f4e6e61e30481dc7d34ffdb24e
2842 F20101130_AABIUZ barron_m_Page_046thm.jpg
0821bdb2612210ec6eb9d20c4cfe7e73
cd9b49886d7a0ad016cea04d9f3122d1934a8f19
23261 F20101130_AABIWC barron_m_Page_063.QC.jpg
7ea92f1b1ea9d065a1846a47f45a1c44
0a1dcd638ba24ebaf412a55ab7141012c36c88c3
F20101130_AABIVO barron_m_Page_054thm.jpg
30e19afee50e7044f91ecf2e1743799f
3de36b511b1a61351a613fbebe65edeb7ba2a19c
6490 F20101130_AABIWD barron_m_Page_063thm.jpg
64960808b7efc226b5eeb9c525355c15
b84a063ca044498dc8a7d5c3a5b7dafc7edf2d0a
5920 F20101130_AABIWE barron_m_Page_064thm.jpg
092089af0871e9dda1300f694453ba58
ec205acbeaf1ff511f1dda9137c1a13cfea4589c
7632 F20101130_AABIVP barron_m_Page_055.QC.jpg
bf8075f27ad6aa522d3067ef4b4093a0
b6b1216227888dc22809a3ef9d5a0697b5242f21
21335 F20101130_AABIWF barron_m_Page_065.QC.jpg
3a8b235b99c3ce3545de987b3fae8502
fa52a779beee73191836b9d6854f847c9d72d18b
2398 F20101130_AABIVQ barron_m_Page_055thm.jpg
a29166464a523448c1be63900f296724
0332ebb999ddd0a807c6a561b659c56c30f7fb4c
5956 F20101130_AABIWG barron_m_Page_065thm.jpg
77fd98451fd503033e4317b592add0e5
002bdf29ac04747a0503a95e5202ca5366ad4c0c
9758 F20101130_AABIVR barron_m_Page_056.QC.jpg
5cf9674160bdc28a1bcdd5aa4bc91f31
ab7550b26368a31841bca9961097f9d82d29021a
23286 F20101130_AABIWH barron_m_Page_066.QC.jpg
ffb366796742a9162c6089e989baec50
1e30aa17aab912392910a8e92c07f215fe81fe9d
9536 F20101130_AABIVS barron_m_Page_057.QC.jpg
678288805c1219653fdcb41b8cceb9c5
2fc2e572b251d25b72a4464ae566ee06f9a8dbe0
6331 F20101130_AABIWI barron_m_Page_066thm.jpg
93db6f1042f1dbcaddaa358b9bf2e9fd
574f27d78e76f795e94c9c70eb1a356f12b75441
7560 F20101130_AABIVT barron_m_Page_058.QC.jpg
ac5fca37bf1705e0858e76790d85e290
748b44228867a24f5c3cfee7187eb66e11943650
23364 F20101130_AABIWJ barron_m_Page_067.QC.jpg
633ca18fcbf299da12f885267e1d4d37
ac75062b9d0a0532ec378c0eb70d3d67e857cdd4
2458 F20101130_AABIVU barron_m_Page_058thm.jpg
f45cc99b6b935080f5262763d0414fce
a596d674fa936d9acc4bdd0088e1e3528064c6a8
6392 F20101130_AABIWK barron_m_Page_067thm.jpg
07e1d278fe1e155dfd9ded09d580f965
354028b9c28d9a0525d28b0666dbe40910db9e5f
2414 F20101130_AABIVV barron_m_Page_059thm.jpg
52c60c948c8aaa1e148b015df19670f9
a5ee267e670a4de6dab1c9f2e0c4dc77517098bb
23203 F20101130_AABIWL barron_m_Page_069.QC.jpg
48df39129c96af78a6180d360326b47d
7ddbebdf961f89063b495269766b52e0eb1775fe
20957 F20101130_AABIVW barron_m_Page_060.QC.jpg
96f71950b347bf45dbe06a765f9eff6a
8da9ea75018808b0e5ee2aa7b3f9554f15c43a5b
F20101130_AABIXA barron_m_Page_076thm.jpg
9230717f923fdb2a4920551a15b80276
4e91a9a6104511ec8aa2c38f0105da80fb3f86a6
6467 F20101130_AABIWM barron_m_Page_069thm.jpg
e2ebca83fec02f7445e314eec8d048ed
b5f36d2d724bf24c18c2fc3a6a198685e964973e
5755 F20101130_AABIVX barron_m_Page_060thm.jpg
d2f1cd58ac65e6416da1f07e57eff144
be9415603d2ddd4435239f5a0930544b66dcca19
24157 F20101130_AABIXB barron_m_Page_077.QC.jpg
1f2afcd0b77bae15ae315144eca7fabd
654244a795c21abddf0b7ab13f8fa60e8828d68f
4724 F20101130_AABIWN barron_m_Page_070.QC.jpg
8ac8ff48abb6eb1e186b1d5b3369838a
826595f764832f1ee24e54976466b64b1cf668e5
22254 F20101130_AABIVY barron_m_Page_061.QC.jpg
2f45fbc9d9b3fcaaa668e950573d1bdd
bae11ad8821de77b8b34b9d263c79093a6f76c6e
6601 F20101130_AABIXC barron_m_Page_077thm.jpg
0ce5789b38f920c588733323f23b95da
ec392de35b7893703300a865aec99ecdab1e0283
1714 F20101130_AABIWO barron_m_Page_070thm.jpg
0761fac462579bef8746925cdee3ad59
ab471b282b617f11f09daa209879147c3fbf15ce
6302 F20101130_AABIVZ barron_m_Page_061thm.jpg
c6bec662243507f60442b29dcb652ed6
09d6c507cd4f9c53118277ae4208068df4d64352
21395 F20101130_AABIXD barron_m_Page_078.QC.jpg
e24d56df03ac71ef61b91d81932c3d9a
f858200213e3de293966ac6601eed8d2f8897ee8
15068 F20101130_AABIWP barron_m_Page_071.QC.jpg
dd672754de9e68cb845d5b34cdd20c95
fb54d948effd300370a6e0490411172605cc12bd
6226 F20101130_AABIXE barron_m_Page_078thm.jpg
56d9d9bf5a1e3b6f8a178bee0fac6a32
8ff96128d0fd69d978ea5ff9912d77927d1b4bb6
23113 F20101130_AABIXF barron_m_Page_079.QC.jpg
b72f3c6da5669c1cd88af6de45b87b37
5ec541afeed3db42311c92faf1f8adf8e4ca3975
4268 F20101130_AABIWQ barron_m_Page_071thm.jpg
140a897ca84e29e97034eb1c30097f47
0142902886083ca9a18554c4299c93d2d11044cc
6534 F20101130_AABIXG barron_m_Page_079thm.jpg
2205d125c1aab78f2d7b0b031b8b0b56
480c56612d18a9ebcdc14a3896d091ef0422105a
9102 F20101130_AABIWR barron_m_Page_072.QC.jpg
89a9d194e8afb24654268f53d5039034
fa2b6754c4cee9df596135b635e70dd4f74a42ae
23823 F20101130_AABIXH barron_m_Page_080.QC.jpg
bb27ba2bd1c048b1e8a8784d2becb96f
54fbc2fab3015caac41946594ce7b92ea630c562
2670 F20101130_AABIWS barron_m_Page_072thm.jpg
5b22082f0af0b02539ab9096f81d86be
9c5b990662bc862e864b5eb4dfb7f8df26cb167e
6724 F20101130_AABIXI barron_m_Page_080thm.jpg
24450835cd8ea890d023dcb479a92f89
bcc77891ee8ab2f3e62d348331defcb12d3a04a3
6844 F20101130_AABIWT barron_m_Page_073.QC.jpg
a778cfda9ba73bd17a303af936283b46
fb9d166b6ba4cd79ab316b06e81400d34c429fd8
71520 F20101130_AABIAA barron_m_Page_022.jpg
d32314ee8dfcf2faebb6d9fbaf35bb80
1652b68482894f39fe3cab41821b61f477f32341
23299 F20101130_AABIXJ barron_m_Page_081.QC.jpg
da01c728e23cce4ccdc8b0bdac20915d
4d7300c6da256c0417c9d7912e3fb5508d461fc9
2426 F20101130_AABIWU barron_m_Page_073thm.jpg
45826e43983cd0b8af1c33bd5bca4bec
4347dc296f9967edb95cdfabcb785b67a5c9b74d
72666 F20101130_AABIAB barron_m_Page_023.jpg
d7fbdd4307b61cc5e772ba3d54c554cd
409f492c8d1068a4ec825da9954a1471a44290fd
6544 F20101130_AABIXK barron_m_Page_081thm.jpg
67b88085d5ed3618ea77fcb005a0bc27
5d9301fbdbd1194ce478f6db6c6a2143ec76f33c
6898 F20101130_AABIWV barron_m_Page_074.QC.jpg
592326bb6405659e7e3c1305413efea8
aab254bdb9caef1a045606dd702bd315245a02b4
24798 F20101130_AABIAC barron_m_Page_024.jpg
948174c255ef89346d66dc6c6aa6f457
87464e0718aefdce278995335154bb65a40b4b41
6478 F20101130_AABIXL barron_m_Page_082thm.jpg
306611eaa24e3338f752f3b7ad22e44e
65d99bbc31da77eefe7f693e33455d58a7555db5
2461 F20101130_AABIWW barron_m_Page_074thm.jpg
5491d8107ef9ab0fe9ac023571fdd43d
36c71b03658388fca484d406b6809885744e90eb
67679 F20101130_AABIAD barron_m_Page_026.jpg
2f2e806df5cde01fae5f29bd4c6aed8a
d8d03d78dda7e2689c5ec2f6e8f6d6faae8e8114
5834 F20101130_AABIXM barron_m_Page_083.QC.jpg
45f9a14d6ffc52682b15a8740ac21b02
e0a642562002e5f62f68d7bce2d69d1082556276
21561 F20101130_AABIWX barron_m_Page_075.QC.jpg
148490dc1ee1452a95b8b5b3f69e80d9
04643e052e28f3cc0c9d21ac6ae8ad1b25d2750d
73421 F20101130_AABIAE barron_m_Page_027.jpg
b69d94aec36f151c5507832fa9b9e2b3
674d63fde3af457db15462b3593401468d99f054
23080 F20101130_AABIYA barron_m_Page_091.QC.jpg
3856db80720e8a25b92cbf8259e61a74
6c9a4a185731c6724021fdbf1de37cd66d450ef7
2044 F20101130_AABIXN barron_m_Page_083thm.jpg
ced4a284e0b1270910e805ab10d5f115
de80ea3c92d6a716c5935b8e104efa78bb3d7aef
6006 F20101130_AABIWY barron_m_Page_075thm.jpg
22b8940110dbecb58a3b2e6c12437999
6cec33830a95d6e674f2bd3609b9008cdf48c1d6
67278 F20101130_AABIAF barron_m_Page_028.jpg
90e320f220161a8ffa810f1a4e9248a9
0c5b678ca9b13f39a864fad158a197c28e3b92f0
6471 F20101130_AABIYB barron_m_Page_091thm.jpg
7c1da985c092c08862e1f89bfa92397c
a88ce2feac0ee2ef7385c3219ebbaf1b0a700fac
4595 F20101130_AABIXO barron_m_Page_084thm.jpg
46ee7f3d178b67adad862a00d360ced6
9bd20f6dc39ee3e274b7d731f1b0e1bba0e270d9
23009 F20101130_AABIWZ barron_m_Page_076.QC.jpg
99134c4b231fc86ea8be53067dadf429
b18356e9f1fd22cda40ee24150a942d8805b2543
70154 F20101130_AABIAG barron_m_Page_029.jpg
a727428c4c295fe22154a27888059bb3
de3dd104ff50de3606fa5704df4b5f239b3f894b
6154 F20101130_AABIYC barron_m_Page_092.QC.jpg
901085541fc83ec72135df9b41bb5534
ac8a358c1072282018d702335fea33dfbc47138a
11501 F20101130_AABIXP barron_m_Page_085.QC.jpg
500b19d82911e0aed3efb6a54d69f256
04d5d6e1768bab481d042b5176cdf97c0fd79686
70739 F20101130_AABIAH barron_m_Page_030.jpg
3bded946af79634095de38086262f4eb
1755ba10bb3ff6255826bef280cf8e9579ee2975
2161 F20101130_AABIYD barron_m_Page_092thm.jpg
b58829979159edd0eae0753a7399e4a1
3cabd037979e66a5b33540f02d585fa6979efc1b
3562 F20101130_AABIXQ barron_m_Page_085thm.jpg
cb89a2c797e3185aed91252be9559d9d
d71a2124cb5f5d3cbdcdc3bfb37c2250df2f1c7d
74429 F20101130_AABIAI barron_m_Page_031.jpg
8406d78f8a2d5fc6f940a0c7ad472e8d
17531fe7e33706da95bfb189ba892c55a74fcacf
9709 F20101130_AABIYE barron_m_Page_093.QC.jpg
54bf7a9920c1c7d3cc90f0b734f253d1
85a66e2b593597aa419e10be22f0e51e46b6acf8
14918 F20101130_AABIAJ barron_m_Page_033.jpg
ca60ed06c1a4773eae9e63f470e82ab8
400dca4fd792f8e11779afc5df140316fbf5ad7b
8329 F20101130_AABIYF barron_m_Page_094.QC.jpg
196e900affbf6536c2a6af64fa8e5e66
30a285364778d96f13007ec72d776edaeb123bf7
6660 F20101130_AABIXR barron_m_Page_086.QC.jpg
a19ceb0a53741df40d95692c550f23f4
bc6956367d9b4cc80181a18dab08f8a30bd186bc
24887 F20101130_AABIAK barron_m_Page_034.jpg
034cfbae20de37bb93072b6ec8369d79
6bf568fc025030af75b257fd98b804e52604124f
2852 F20101130_AABIYG barron_m_Page_094thm.jpg
d8af915b47b9a198a65cc81404057219
9e7cd16f604528bc48921092be32538f18d615f2
6984 F20101130_AABIXS barron_m_Page_087.QC.jpg
192eb58417ae6c5cb03d9d9e73b6b9fd
557ff5cc59184367ade1f97555a4988e5516228e
27533 F20101130_AABIAL barron_m_Page_035.jpg
d7281abd11984aea8590bd31c5a926c5
469392fb1a8190b48127a12a7e79e3473cb59e91
8522 F20101130_AABIYH barron_m_Page_095.QC.jpg
24e1975e0b91eafd501edb4b9201c532
2766b9029b0220e4dc97123d54e39c6f9885487a
2331 F20101130_AABIXT barron_m_Page_087thm.jpg
207857d36735b2dac5e05cd79699a353
062f7eef59e0ffc1074a1a9c0d39666bcb59da6c
25940 F20101130_AABIBA barron_m_Page_052.jpg
9081d32b09815c35cc6301474beeebc1
db3ddd19ba43a6ed04cf396cb3b59f4bb3a0a4ad
24742 F20101130_AABIAM barron_m_Page_036.jpg
54b51a39e29f288e5370c9a260816274
db83f08634788bb21dedf54a3d5a64493e50653b
2910 F20101130_AABIYI barron_m_Page_095thm.jpg
47a6c2e56d320a1719151edb113ee5a1
2441e72f6ff17176f5e334d137b19a2869455999
20515 F20101130_AABIXU barron_m_Page_088.QC.jpg
9ab14c2d480e3c6a18417f451c19af12
0672c09d7eeea209a3932d10f650c38d05e17496
24945 F20101130_AABIBB barron_m_Page_053.jpg
c7fa1681e2403971d18f70be1edf801a
d7d224053546d0de2216da4fadda8f9e3b27a912
25593 F20101130_AABIAN barron_m_Page_038.jpg
4fde02ccc5954b7d81a3ddf921e9dac0
dd345eb8d69f26db12abb3a115bec15c57b4284f
8019 F20101130_AABIYJ barron_m_Page_096.QC.jpg
d5abc8771a930c33fefc5a10fd413939
cebe90f6df5d89513b011cfd128c71568720a11d
5856 F20101130_AABIXV barron_m_Page_088thm.jpg
7754ea2521acc8cbe3884c0cf7b8c7aa
5cf0bd3957e5b04224c44e292871aa00ef30b404
25673 F20101130_AABIBC barron_m_Page_054.jpg
5ab6c6082f37e04c41a8fa403f3a0c8b
7a64d7f1b8ced475f008e0cfba31a9405e8d15e8
26342 F20101130_AABIAO barron_m_Page_039.jpg
7b85a5ba07dab041703327f9c788f62d
86bb09683fe4a28b3ca321b4aa89e2e503cb1f84
2795 F20101130_AABIYK barron_m_Page_096thm.jpg
d1cd60ffbd4c7a76f3a02f4f6e7738d8
8bb99775713c2d687ff0ce08970f23eba2e0180b
24023 F20101130_AABIXW barron_m_Page_089.QC.jpg
9691d333f4c17719660b4f1268d85ef9
3f3599a4a7b84bb6193bc41b7a86ac8bab88c520
25801 F20101130_AABIBD barron_m_Page_055.jpg
1f08de6f55d9081711b2ff6ef731f761
75a2c35a40e0e3a1d5506b72e682cf07b424e456
25569 F20101130_AABIAP barron_m_Page_040.jpg
9f49e22738693344314ab9a47b955a66
b9e5e4bda0fa0f1cda8f1f2c7aa4a67afd420442
8289 F20101130_AABIYL barron_m_Page_097.QC.jpg
22bd0166d8e54e8ecb6a3fe8f74006f5
bde67afb2bdbdb88fd88555e46550aa5c35afe48
6553 F20101130_AABIXX barron_m_Page_089thm.jpg
9dfdd91089b341770a406cffe3a80be6
1107f468d8ad0dc8a7b73fbda368d167e1ce2376
31622 F20101130_AABIBE barron_m_Page_057.jpg
306f00c40f9198b1e0bbd1d87e5ab9c2
e0f764c00f1154a0469e692c0437a58029ca4183
26198 F20101130_AABIAQ barron_m_Page_041.jpg
b77ac167d2335274ba9d66a803041bf3
048555257ee5af89bed6a484001ab1e62da30d9b
6641 F20101130_AABIZA barron_m_Page_105thm.jpg
c69021c474edaeb47fb0d4353943566a
9065eec09a2a675507376694889c3d3b73b1830c
8196 F20101130_AABIYM barron_m_Page_098.QC.jpg
50fb93bef039e01b66d114c3aa9af216
533a4293c617b57c0dcb7a48d33a2a8be961c3ba
22881 F20101130_AABIXY barron_m_Page_090.QC.jpg
9c1d678d37f91e3ab5b65ff76e8802cb
d2ad98976a1a257b0e263328ba851a870ccbd482
25642 F20101130_AABIBF barron_m_Page_058.jpg
72724587d893890461edfb1936a137af
a1ac685491fa2360128a038aaca05a1a60a83cba
26335 F20101130_AABIAR barron_m_Page_042.jpg
628656eb3511e3dd11e4cb0e259cdeca
a6225b9b480dfabe1649d1690abe31b6650db501
25756 F20101130_AABIZB barron_m_Page_106.QC.jpg
8f737bd07a6ccd3ffb5015ccfeea2a70
1ca5ebd1b87f2dd3a7ca1a2e54967805859fb67d
2858 F20101130_AABIYN barron_m_Page_098thm.jpg
73a3314349c3ca00e364676388f26f70
63614c99ff34cdb46f0851a96fcfc3400cd18759
6584 F20101130_AABIXZ barron_m_Page_090thm.jpg
5783a53d658cf5504ebf4101c39eb244
a920c5655655a928f24a2d574e0ec62fb6e4a213
26114 F20101130_AABIBG barron_m_Page_059.jpg
27c2429d9ab47c49d3b68253d03f5814
f41954a5ede1bd50f77ca9621a79f8d98444d8bc
25529 F20101130_AABIAS barron_m_Page_043.jpg
52ab4132e4263aeceae18c1c91477b27
04cb68cd0767896170944c139c7bc3dae789cb2d
6725 F20101130_AABIZC barron_m_Page_106thm.jpg
a543ded41b7969518f6ac2881cc6bd7c
57762f43791e53a7684a7324ae3776f6c4253c88
8410 F20101130_AABIYO barron_m_Page_099.QC.jpg
8bb15fb189ba88220474d3ad31d7ada4
08d954ef97a49e6dac1d8797ee839610e1fc0e8c
65526 F20101130_AABIBH barron_m_Page_060.jpg
20b2937c635209c185fef153111cee8d
c4c85222e8e5dea12c4c7801a6d1bd422eb71009
32322 F20101130_AABHWB barron_m_Page_056.jpg
4b276ae20cebb2df4f0b237b3f948ef2
39d082bc93792c9b96217eed60702705d944d903
26374 F20101130_AABIAT barron_m_Page_044.jpg
1bb99ebb4b76f9914f72291ec40bf00e
fcc292d1518f5cfd44222cc1f1dad18cc2879d5a
21787 F20101130_AABIZD barron_m_Page_107.QC.jpg
7599a305daf2b7ec7d42e709a530ac13
1d42ae33621fabbd066e3957ab44d95c697e7ae5
2881 F20101130_AABIYP barron_m_Page_099thm.jpg
821e4bbccc7f2e3247f6dfb939c854fe
37e65bb317a889048de44b6b59d8e859892c5cac
69246 F20101130_AABIBI barron_m_Page_061.jpg
fae7de3564324196bb3b730c7e334d6c
6aff63750cadc62752a5ccd2ecbe1aaceeb3a1cf
29144 F20101130_AABHWC barron_m_Page_037.jp2
8efd36be313ad7b88081ec66e8cf1b6c
1ef03f416fab9d0f86630e8328b1f619cbd0b9e2
25252 F20101130_AABIAU barron_m_Page_045.jpg
5cdbe9afb163f5512a44773ef83b4659
be4c546eac2c0c09c9ab149f49ab70da1290a69f
5908 F20101130_AABIZE barron_m_Page_107thm.jpg
ef9b65b2742088bafd182f3ffad787c8
5e3889b704de55417489d47ea275782a597dcc5c
8296 F20101130_AABIYQ barron_m_Page_100.QC.jpg
f7057139c3f1160efcd00d73feabe9d1
d10f2f55afddd3b3ae7ade5c9ebdcc7218ef8bcb
73756 F20101130_AABIBJ barron_m_Page_062.jpg
2a01ed57fbb7816cea593410fa5cd97b
a33d6149183716db0b4948e62a767ebd0400f946
24673 F20101130_AABHWD barron_m_Page_008.QC.jpg
773331d6fb2635b3d4b9dbbe7a6920e3
55a59fea4b374956c97df712a7f0aa0561e24d6a
25105 F20101130_AABIAV barron_m_Page_046.jpg
f969481f5ad5cae81a562916cfa4b862
b4cc3c541a5d94f749c80954204d1d74635ba6c6
9882 F20101130_AABIZF barron_m_Page_108.QC.jpg
3525efe4d2144e5ad36514dd144b35bd
31d37d0d7ff1cb3641da728e3b202647f92f8e15
2879 F20101130_AABIYR barron_m_Page_100thm.jpg
d33c4ff4098cfcb14a58b8211c7f08ef
2097bdbf26bb833633e17d32237f3121816ed687
70965 F20101130_AABIBK barron_m_Page_063.jpg
3a51dcad18a50e66c5310df09c8b204a
28bf07ebeb173f2c7c2c3f7f2640d23c9fa4de10
73998 F20101130_AABHWE barron_m_Page_017.jpg
c7dca3e345301f74f02703bf431aa8e4
9090515735ef32c974b156c48f3c3d5f0a9fe061
25605 F20101130_AABIAW barron_m_Page_047.jpg
386df99f5dabacb924e6b5919e11ee95
5af13c1e9489dd8ea315c6295adbbbe6a3717e1e
3105 F20101130_AABIZG barron_m_Page_108thm.jpg
dad58d41c5ce61af6b8e758b14cc7e5b
fa68c3b46b609913cc36c264ce58b4ad3f3d0af9
62900 F20101130_AABIBL barron_m_Page_064.jpg
e8fe491d9b5985f260061706f2b69202
5df50eb9678d72181b9340c7726dd60b5db52cc5
1053954 F20101130_AABHWF barron_m_Page_015.tif
a9cebdb79b24358a01038095e95d9234
1eb7766b686a59a5141d95436d654882095756ef
25273 F20101130_AABIAX barron_m_Page_048.jpg
cc881e8dfececa37d6b1b0bfea5dc1a7
3ecf8bcaea4300ab71f3a1aebd66662d95ca8b86
125326 F20101130_AABIZH UFE0010801_00001.mets FULL
29bc7d941fdc91b1f5d12b1f3900cf71
524f648d92be78b7ef1ec10dedf07bab6b17764f
8724 F20101130_AABIYS barron_m_Page_101.QC.jpg
8d85dba48f9a846b1279ce49c6d10571
4881d331fc22bda2dbfd1d4a97dc4f33aa5e7fc6
65917 F20101130_AABIBM barron_m_Page_065.jpg
3e5adcb480e780b0c3d269c831646889
9ddcf39977e4a2ca04f77a1bf37d4be35714d7b2
30064 F20101130_AABHWG barron_m_Page_047.jp2
3ae863b377a74390fc5cd910defbb4cc
31076701e43c5caa9c23820d8fb04d7974749d82
26546 F20101130_AABIAY barron_m_Page_050.jpg
4ac2816a51157dbf1016c748ca536f76
4f8cd94ed197e48fd7448fc72f7d0353a60e938b
2948 F20101130_AABIYT barron_m_Page_101thm.jpg
3bf944e57d7ff66492d1227aa4e22be1
d0a35a81331afc4852c8c19f4d02a28b7f1500bc
72495 F20101130_AABICA barron_m_Page_080.jpg
d676856fe94affd88747953d51f9e97f
a458f0356c5459f922584dc2bab2ec13a58393f8
29352 F20101130_AABHWH barron_m_Page_034.jp2
ee5ef69b61c3547d016bafc790ab7209
3de32353f89f72a83a740a0434b356cec8fa4c6d
25503 F20101130_AABIAZ barron_m_Page_051.jpg
ed85388a0d440735e77f1d69a77b1b18
8b5b1678f2b454fd95088ff9d1ce17dd69b6e7d1
8194 F20101130_AABIYU barron_m_Page_102.QC.jpg
5f57683c2f53d680a4f4c54cc034b7f9
0d461052fd2e49db0038c6ca53cdb2e08f580d85
69963 F20101130_AABICB barron_m_Page_081.jpg
f0b43dc3340edcd23c48f3358616a9e2
e6a882886aa33d2381225fc93e8424cce15225c1
70405 F20101130_AABIBN barron_m_Page_066.jpg
d13b2489208e7ec8a69c71e399e4c410
9dc5ab5dce295b43dd1319fdb4832e6fb2f2bbc4
71186 F20101130_AABHWI barron_m_Page_067.jpg
fb6876e7ee62f04f60ab2e83147edb4b
e29f9cc118c50963dc225ecf0f74b3416fcbd668
2774 F20101130_AABIYV barron_m_Page_102thm.jpg
fc74878a952f7489e404ef1d161de576
869079f4fd6980ea5989e86b39cc54f45bfc083d
71592 F20101130_AABICC barron_m_Page_082.jpg
c2edf1a3ac7345e0a4e2f90b7d889616
9d9b9187d1865d6a7f15a08523dfd6245f111695
71141 F20101130_AABIBO barron_m_Page_068.jpg
ec61e9441bc67b9e240a348c7804678e
47acecb3d3b6b65cb473d31dbaa5f9685b6e6b66
64194 F20101130_AABHWJ barron_m_Page_025.jpg
e6201f39cb6d5ee060f95e19e3324afd
a50520dfba3d806cf5fe5e732acf4c535217e76d
F20101130_AABIYW barron_m_Page_103.QC.jpg
7464ebeaf390c80a59c430f45447975b
10186b16472c7f858a4a2631d34574c8a0e69c83
16882 F20101130_AABICD barron_m_Page_083.jpg
364f0262f8eb2f32e887820151cb5c4f
5fa63856b4c9da8ee18a8bff6520abb18674771b
70883 F20101130_AABIBP barron_m_Page_069.jpg
4b6adf00af2a342ac8e64b72998baee7
e0c7c87bf1a6f8474a4a02cb6d656405e2329a99
25994 F20101130_AABHWK barron_m_Page_102.jpg
b190d176efa7b95c4a41aa24f2fd549d
c307466b0348a8b4a288049c9dd80818346fc431
21702 F20101130_AABIYX barron_m_Page_104.QC.jpg
e10083ac4fc3bfb5a7f09228d43b4efc
a4efc37fd1266148b4d85d2143cfc3d4818167d0
45631 F20101130_AABICE barron_m_Page_084.jpg
957f7bc1365eef2c170e2feb8edd13d4
2008ffc7d260b5ec5ac86155e182ecb05d0d7143
13808 F20101130_AABIBQ barron_m_Page_070.jpg
7956dd4eb3c6c7af5a91734ded9cfc6b
71f740fdc7d2c3e98aba8fc2b85604caa26243aa
F20101130_AABHWL barron_m_Page_084.tif
62b8d96486f1d740cc191683ccf9898a
1a7c83a4fb610a74563fa0d9f6d07823f14b5eef
5919 F20101130_AABIYY barron_m_Page_104thm.jpg
3c6182899f2121535d7e41af718ebe26
337acad917c289207ecca2b3bebb3dc2c53706e2
35319 F20101130_AABICF barron_m_Page_085.jpg
782a95c7e3be3184541d51a7dfd53f88
74f37627d75b39c17beceabf7bf05484988125c6
52165 F20101130_AABIBR barron_m_Page_071.jpg
8373893d7c7c3b438f652262ccb12feb
e1ec7dc8b7392053fd14b005326618426d9efaea
25873 F20101130_AABHWM barron_m_Page_098.jpg
cd8888639b5ff3b46d67ead5fce661a1
9ba126c1bd2771863fb1cb372ff5275ba67fdc7b
24988 F20101130_AABIYZ barron_m_Page_105.QC.jpg
3913ffaab48b416c4f98ea391469cab5
0eaade07689eccc192291eb66783c0f351af166c
20116 F20101130_AABICG barron_m_Page_086.jpg
31ff027b6e35fb0c9f11adc88981ea96
6df6b77e11a3446c60391505efbf72daef60907f
5279 F20101130_AABHXA barron_m_Page_012thm.jpg
c214a031f6dd5a2b7b0d1aace9f8a782
867e773ac1562c90870d43fc1cdc1a38081cf5b8
30396 F20101130_AABIBS barron_m_Page_072.jpg
4bac1f77f097f7acf0206507ab4e7c2e
d630b2ded494dfff52dc5273504edd8d63dd71ca
719 F20101130_AABHWN barron_m_Page_108.txt
28a6bacdd008db8b255bd4db1ac6b072
cdf954dd4f65c481d37512c724725b09c9debcae
F20101130_AABICH barron_m_Page_087.jpg
919132c1cd7c16aea7c1c399bb13e179
58b51a48ea92007d5676fe5c1dc4824c1ff5bf43
F20101130_AABHXB barron_m_Page_038.pro
75237308178a5a1507a1650de00abe31
046913958ed393d0371012225aec18a89a74ebcd
20846 F20101130_AABIBT barron_m_Page_073.jpg
c3bb3d1185fc12a3eb3bc7c4e29a2c51
c087643603234afccbef50476b3d70d2d444bb9c
24459 F20101130_AABHWO barron_m_Page_001.jpg
8a4d4e7b73ac69996a759f3e1fdacf53
183d70590737481f2e822abc35d888a14eb981fe
62004 F20101130_AABICI barron_m_Page_088.jpg
d837fc1a13b34eb5d91372d1c2c72dd5
e3f81d8dd48e8bcd9e10878e30d98b034c98955d
2928 F20101130_AABHXC barron_m_Page_057thm.jpg
ea6e64c32bd03b18062c14c4f4f3dda7
5dd075fdbe1999b6e5748d3689531617bf4b5caf
20516 F20101130_AABIBU barron_m_Page_074.jpg
8ddfb7d34766faf82559605e425f1883
ec9af381c8213a6d2bfda4cfe5c3e3076fd70abb
102497 F20101130_AABHWP barron_m_Page_020.jp2
b6dc2bbf49b69e7f7de8872cc3919537
9b44da39ba56059fba4260f39af9f8aebe51cf2a
73665 F20101130_AABICJ barron_m_Page_089.jpg
b3e2aced696ad4c3857598786acdb409
0b4eef37bf06d64193fe78381a0d9f0819159d5d
29182 F20101130_AABHXD barron_m_Page_048.jp2
b808162e799acd432464929b8c866607
63baac53e0677c2fc32db7cfa9996fce5acbec72
66265 F20101130_AABIBV barron_m_Page_075.jpg
f5ad2c1b09e248b7795b8d2ad893107a
e894a18f0ce82d502b777afe814b285adbb54973
745870 F20101130_AABHWQ barron_m.pdf
816d3b11ab2b658a59455100e7cbc29e
c1daf587ef76079ae3795415641f50b06c944611
71580 F20101130_AABICK barron_m_Page_090.jpg
629d2fe1078cf743f92b17d5600ad5b9
d8cb8247f153203bf32501bfd75a4b0ebb39a68b
28842 F20101130_AABHXE barron_m_Page_098.jp2
48b1a5c00cd1bdc2f5e1213ac82da86a
c4e2f5c41996520cb95a042809c7988d7b5d7a48
70953 F20101130_AABIBW barron_m_Page_076.jpg
8c89344dab6035b8e2876d6aa72acee2
b2ff321ecb66f59d6fcbbe785e212c2109a2f186
70995 F20101130_AABICL barron_m_Page_091.jpg
e7e70d5b12ea7c949efdb45ee9b4f8b2
26d544cfec2856a39eaf2da7f965e40322df82e6
3089 F20101130_AABHXF barron_m_Page_093thm.jpg
90a0035754a87c5d8affabcb5fdb30b8
e5f42ee56fedb40b5e4fcaba414c9efbdcdca4c1
74088 F20101130_AABIBX barron_m_Page_077.jpg
0fed5dece3bc2814200c97f33d243c5c
2237622073ea781b8331b0438f439445ff921320
109038 F20101130_AABHWR barron_m_Page_090.jp2
824ce34d041a263f51d84d4f93b922e0
06094de151d916cc9ba59f56d6c93d67abc2145e
30667 F20101130_AABIDA barron_m_Page_108.jpg
96ecb96776573e08778836987027fb6b
1af1ab7da24fd074c934d9de6b6812a258cf7ee9
18553 F20101130_AABICM barron_m_Page_092.jpg
477175975880bca2f891d7b952d7c837
62b8e6c3b91ff58567c2199407d532c3bb862079
29269 F20101130_AABHXG barron_m_Page_100.jp2
95c238239dec248e0beacb8ed1c7d612
77dc786a86c74cde7080e06b14c5e500f45ee6f3
65539 F20101130_AABIBY barron_m_Page_078.jpg
e805d16cf49a53d2efa06bc71f1a3124
5a84c34a08ad91008601f0343d0ef11eb8594e38
2849 F20101130_AABHWS barron_m_Page_103thm.jpg
f9e8c55ae3a4b6a86098130d8235eb2d
948890a20c47a4b006771bd9b82ce5ec7dd9ffe1
25798 F20101130_AABIDB barron_m_Page_001.jp2
245ca0c426dc68bf0c7f75a26b317ec6
98afbb916893b645ecffe1954fb715a11e62010a
29365 F20101130_AABICN barron_m_Page_093.jpg
3911ad1c5ec8f9be3f821d81673f620d
e3c1da6c6e4cb7a54ad7e0a7ee426bf5093785f9
23623 F20101130_AABHXH barron_m_Page_082.QC.jpg
b9faa9b0ce207982ef3f82d7afa4d360
386596841194b85de320f64786f7bc9fc33eb368
71164 F20101130_AABIBZ barron_m_Page_079.jpg
f9702a7f060d08ae96db0fb4f2fc4c34
77441886f60ba1dd019e3118abeb0bfe6f5d5ed4
2565 F20101130_AABHWT barron_m_Page_001thm.jpg
e2d94d316740222db15fcebcb0444281
c6a9bfcff2a7a4b740ff88e2fcc7a7bc529a24dd
6067 F20101130_AABIDC barron_m_Page_002.jp2
fbf18158d76eebc3e6075d56ff6c94c8
6cd08026ac6fccabbf596739f013ada02b98954b
26594 F20101130_AABICO barron_m_Page_094.jpg
8bb38cde4bbb2063ac2f5b19a301dba1
bd5c8c6f12c3177a06acfc5b04d3f8f6da553a33
70682 F20101130_AABHXI barron_m_Page_013.jpg
2c1c26ee76a0032957f2452daa47036b
f20e86ec3749f12efc62a562b1e9a8c607750320
25371 F20101130_AABHWU barron_m_Page_049.jpg
2c77b30dbf4b326dd77a946b6a66903d
6cd39a1f6a93411d435d2b91d8096b4b370c8926
81886 F20101130_AABIDD barron_m_Page_003.jp2
0902eeb9c824b290686ef55ada5a0a77
83fa6416e11341f34d0be6ee42b9980ca7d3ba7e
26615 F20101130_AABICP barron_m_Page_095.jpg
2c4a3d38a85222f8a580e573cb4f8c40
397b1e0882c4258608202bbe26d9f2d4f6cc5044
6500 F20101130_AABHXJ barron_m_Page_068thm.jpg
53088afe698c4e4b795a8c45d79081c0
809a34163188344e6cf0bee359a1a0485f039cca
38133 F20101130_AABHWV barron_m_Page_072.jp2
5a1a12933b7b7d4877a39dd6cdd8e9ac
544212698967a8a1a33acd1ee45685f8e0bd84a7
1051980 F20101130_AABIDE barron_m_Page_004.jp2
1bcd6eb2d84825e5f1b6cdc19aee12f7
534f6b264be955d84d453853866c36713ebd366d
25705 F20101130_AABICQ barron_m_Page_096.jpg
e9e0029a3ed97144a39a0ee4153e09a4
100216cf9d8f96495f602d619926d59fdbf22faf
112419 F20101130_AABHXK barron_m_Page_089.jp2
273fe681925ab110a2f217677a06b05f
9f204065f427c4826c578542564071a5a94185f6
31961 F20101130_AABHWW barron_m_Page_024.jp2
f5f7942c4cbc9cd8b43db9004ed31913
1f1216658fc3613e5d753c209c5916a5f8fd9647
596578 F20101130_AABIDF barron_m_Page_005.jp2
5aae33893804f9c821c09e2f16587508
39775e9877b156cf6e352117a3d7ddba69701245
25884 F20101130_AABICR barron_m_Page_097.jpg
9c8d73d46f9c4383e297ea66d097084f
187181c26fede24de873f2414d20f77019c0c26f
9466 F20101130_AABHXL barron_m_Page_049.pro
e43469ff16b6cf4970c841f72187602e
3419b0d461974c082036aa04a4281c62c810ae4b
2280 F20101130_AABHWX barron_m_Page_005thm.jpg
d55d630e05e76d597f4e07773477076c
0c917932fcc2c0a6fdf683df41c5f47c4a8513d2
1051961 F20101130_AABIDG barron_m_Page_006.jp2
78d342a32c38918018b948aa50d0ca8e
3dc6ad9783be33d180da93a75971ec67d76d7102
1819 F20101130_AABHYA barron_m_Page_060.txt
c77e5cee0f36cf76a09bfe67ee0816af
e951ff13e7e7cfd6c867bb5db761645dd04b8c9d
26308 F20101130_AABICS barron_m_Page_099.jpg
51bf05d97ff14792023c7527ebe37af0
2efc1fb895032f20fd7db73c167a8f2e79853f7d
50214 F20101130_AABHXM barron_m_Page_104.pro
ee4a61f3a0f24b927bbd387c4f0c4711
30c47cbdc72d3e671067bb1a23426817bf9a4d68
6501 F20101130_AABHWY barron_m_Page_032thm.jpg
92dccbf1cff5e5c72b028fb7cc32604e
7ab65210f8ae09bcd0f55684b259dadd2cea17a5
1051957 F20101130_AABIDH barron_m_Page_007.jp2
bfdcdd0b372a809591f066105b05c2f6
05484b96808c4609aef88ea0d8695b77876442d2
30082 F20101130_AABHYB barron_m_Page_040.jp2
80dcede9280870c1a58c6f5d228f15ec
a602cc9161a5cce5029c2b32fdc13f494cc71775
26316 F20101130_AABICT barron_m_Page_100.jpg
ff266c96ae2f7919f1e1e8a2b45c7521
7c751dc08f58851b35caad9f6dedd09b3c4947c8
29199 F20101130_AABHXN barron_m_Page_045.jp2
5d6ec87e403d28b73e027a27bae01ddf
87036ced7e6c8eefc43c577cb01ccc9f84bd6e4b
20666 F20101130_AABHWZ barron_m_Page_064.QC.jpg
4f4562139b688322e076fbc2f11b0c1b
b3679579d2891f6f3e35fae1f997ad35fbb0fe6b
1051982 F20101130_AABIDI barron_m_Page_008.jp2
9e259e772297908de5acd08a3bfb19a2
66f645a8281aaa9152401a9e7f7ac46dc544bd9b
F20101130_AABHYC barron_m_Page_072.tif
2ff25cda68612f67bca4e6b92db2cbdd
cf0f8447379869149322716a14cbe595dab91e76
25700 F20101130_AABICU barron_m_Page_101.jpg
74522131fe36ea150a6c66e058f77df5
47d6af5e865ebf4aaba92500c0f43d52cd72ec87
23141 F20101130_AABHXO barron_m_Page_030.QC.jpg
5b9c5f096181ddcfe6f1ffeebb058ff3
b1489b95055f0cbf2200ae3c5af3720da95d2120
F20101130_AABIDJ barron_m_Page_009.jp2
e32163db2034e54a566d9136db1b2cf3
f98431f8d892bf661258fc723d47a11c87b0bc3e
8415 F20101130_AABHYD barron_m_Page_042.pro
4770bcb50142eb06fd4d47c8ae44de1c
bfbcc719372e134a9a9b583dfc8b1f799f7bc9dd
26864 F20101130_AABICV barron_m_Page_103.jpg
503b2c6602d3a3642845694c2816799b
465789d7a823b1c6ab706783d044ec15c3ee0774
2951 F20101130_AABHXP barron_m_Page_056thm.jpg
63632dc8aa70d6e0590cb2588e55e3e6
60dfc4d6090e27768889dc3e5a0b497b1c7fa4b1
1051975 F20101130_AABIDK barron_m_Page_010.jp2
18b951dbc126892c5eb30f38e59bdfb8
70a76c30fcabc10f35c5f0a217f15d54409efa62
627 F20101130_AABHYE barron_m_Page_054.txt
07e4075180c1aea10d9bba5b8129e1d8
0559da909c9ac39d38f17e7c7fc72c007bfd9490
72062 F20101130_AABICW barron_m_Page_104.jpg
a8a7935affbdcf9a456d52b99229d12c
4e8a4da06945e5efcd2bc68feb1edbd0a2bada57
30576 F20101130_AABHXQ barron_m_Page_043.jp2
12b5357ed13025c91d99a1d70c43d13e
cbeb56345ed0f428160d66f409a155469223cb15
743003 F20101130_AABIDL barron_m_Page_011.jp2
86645229c56676100f85a06961119fce
d1d170994a2da687ca6e0d0c695ba7a1f82e8e9b
29330 F20101130_AABHYF barron_m_Page_095.jp2
109c1937942555f1e8f62e7264c3798c
d750170d2284ed42ca5445e7cd141a5b60f9c05c
88552 F20101130_AABICX barron_m_Page_105.jpg
86b070bb0a3fdd2e82b7aa607e0e276f
ea219eb73f27c31cd9a0e2140a5793ea3927b146
1976 F20101130_AABHXR barron_m_Page_022.txt
bd6d68e9a1b23400bc827d08947ac76d
2d4390b59805ad045366d0a5123fd26f6b895917
88323 F20101130_AABIDM barron_m_Page_012.jp2
119367ec2b6b27cfa39e6bf5bbff6e37
ac3b1a6487278e870f47857e9b6577e6bbbd9d64
9032 F20101130_AABHYG barron_m_Page_035.QC.jpg
91b823fcb3862e6bc41255ef92783762
6b1bee25d42caff34e4a0b89cc37a9188ac114d4
88984 F20101130_AABICY barron_m_Page_106.jpg
7c9367955b3d88011777f3fe20f4a2dc
ee77e2558250a00d6ef25c31ce4e719281133bfb
103154 F20101130_AABIEA barron_m_Page_028.jp2
572830d3f79e6a53ceb986851dc164f8
605687ceb54936196094d1c6008d79bce9ed41dc
109231 F20101130_AABIDN barron_m_Page_013.jp2
2d2264f7dfaadb1094da1b30e52788aa
426f0ff349aaa5b78ee7678e61807d39ec04e161
15321 F20101130_AABHYH barron_m_Page_084.QC.jpg
bfcdee609771ef7aa698dae23b4058ba
eeeb37b85ee74ad25c556c79208e38f4dd7bfc2a
77007 F20101130_AABICZ barron_m_Page_107.jpg
856792f930550c9a8f1ca00c03ec35d3
7bb50533fd0667c25b67b28afd929d55935ae67e
F20101130_AABHXS barron_m_Page_035.tif
f4a4687b407d139f949fe4cc6c0e459d
c8f9780b1433d34f89cd4830deb1499f2318a327
106468 F20101130_AABIEB barron_m_Page_029.jp2
9ef613b54dd8e30974e950a908526d61
8a8fc1c72af75a741fb5b7da541acc607cde4598
98648 F20101130_AABIDO barron_m_Page_014.jp2
9199c039b25eebaf80805abcb610842e
501ed16c9d2744a9166d95e0c4a82fec7ef09e13
60913 F20101130_AABHYI barron_m_Page_084.jp2
656c5fa6e34b5f7287900c210416a91c
a111305a34a46d898803bff2ec5a4661d3f23d01
8230 F20101130_AABHXT barron_m_Page_037.QC.jpg
846af6960a88e520ae77355c71c152a0
7eaa901b6cb1c428b3d2bdf8d562ce377209a3a9
109914 F20101130_AABIEC barron_m_Page_030.jp2
1815d7995f0b5decdc143fd7492e3ec0
be178f21f02080c5c0a67af998766775781ecbe9
111979 F20101130_AABIDP barron_m_Page_015.jp2
20e51873404a95cf0330dd79164da511
92b35e1a2234db510082eef8ddfed075e8fd0e1d
25664 F20101130_AABHYJ barron_m_Page_037.jpg
9ed0e8deee96a054c75357c56f9b3405
625beeca1adb323d0113f820df5895ba36a08e91
51251 F20101130_AABHXU barron_m_Page_023.pro
cbe22a320eafa572b467c03a92e5ff9b
d25e0fc89bd2199fdcde52ed724c25e172cace84
115914 F20101130_AABIED barron_m_Page_031.jp2
657e7ce96b5546dcf66b90d15b7dbb4c
d217f908161add8a870f244c857793a45d7dca35
114744 F20101130_AABIDQ barron_m_Page_016.jp2
3f598be272294c9d724c709561e8bdde
c755ab18796bf8df88f2c7a6ba97ad3c3d4650f2
5109 F20101130_AABHYK barron_m_Page_033.pro
c0dc2c9b0d7ea17ed336aa85d6e824ea
9f2209f7d92cd7189d15531b0b567c309f4c7548
F20101130_AABHXV barron_m_Page_097thm.jpg
b37e4f2cdf30159f3b110da9affee718
d3622400a5edb611a0924bf34480e49d22a10324
109752 F20101130_AABIEE barron_m_Page_032.jp2
a101076dbbd463a322b54b559d8fa6d3
bb4e8c3f17995ee9334a8f3eab88efa22e9609cc
112172 F20101130_AABIDR barron_m_Page_017.jp2
3df9e56dba5a1280c4a84d33638e4fda
07b3f2b75a6c26bf23196e17fdf5324c100f5990
F20101130_AABHYL barron_m_Page_067.tif
9c1c328357c171fdb148ab75dffe0c19
e55f3bd6896cb99fbbc3817471cdea6f9238a732
648 F20101130_AABHXW barron_m_Page_098.txt
76b0f154eebe4e9bcf9d305f273d5f9b
aa933da56bd596a2ee759bc2d83f6b4bf25f0f8b
14186 F20101130_AABIEF barron_m_Page_033.jp2
5596d3b80843c09fe289ee607e878989
ed16843857f4992a24a635266fe26ef49d3f44c6
F20101130_AABHZA barron_m_Page_016.tif
7ad5ba5b9582b6133f3dac55aee40ccc
3ae3f380a787938bc9e116645ef73fb6c4bce77c
112990 F20101130_AABIDS barron_m_Page_018.jp2
0f18b9312685b49315deed355f165051
f88c3a041635ba033901404c9515388418a16ba0
23045 F20101130_AABHYM barron_m_Page_068.QC.jpg
3c554f277ddbe43d28c79d241ae53bef
c2518a109e7ab49f8071272f5b864ff2cae044a8
25271604 F20101130_AABHXX barron_m_Page_010.tif
b91b8bc3df92744236c791d3f04d1107
92e66c7e9b98ea15ab599c87f0d0033fd3e3e1d5
33406 F20101130_AABIEG barron_m_Page_035.jp2
07232f6dd3837ed0ccc5775b3558745d
6ca2436cb2627498be26dc218ef43cdd95823f7c
23447 F20101130_AABHZB barron_m_Page_005.pro
af96ac97c0b85bfea67598b4147bdbe9
0b0e6d16dfc7b09467393f04c060075585cfb0a4
107394 F20101130_AABIDT barron_m_Page_019.jp2
82ce66b342736dab5a389c584ea5de65
39f452ef6b77e291c9f67f603b0260036d057eee
2977 F20101130_AABHYN barron_m_Page_052thm.jpg
0d119d66ecea32fe40651984e3c39a97
50900573b0085e239031f7d27bf59768e378f1e7
597 F20101130_AABHXY barron_m_Page_051.txt
14d545465ad3c53220276ba1471ac63c
193bc02162852dd31c90eb6b56dba73bee595f3f
30613 F20101130_AABIEH barron_m_Page_036.jp2
d6168badc00c9a9a03c79b1a40f346a5
7f4495b679b2c7a48c0ff3827e292ba095f03970
72238 F20101130_AABHZC barron_m_Page_032.jpg
3feaa35b239e98451bd2acf7f644663b
0a6e897cd818fb51fae778dd4167d1ba633c4382
112158 F20101130_AABIDU barron_m_Page_021.jp2
c519340fbf038b853acb6c3183b030c5
f8f9c0807aa482fdb2f8f2cbccece2637425beea
2905 F20101130_AABHYO barron_m_Page_037thm.jpg
8c78f30f79187017be06f6ee238837c8
dedaa279b7a9e2993341011ccb70b41e5ab3cc2b
F20101130_AABHXZ barron_m_Page_036.tif
995f02f3c62c0be1420d23cec836045a
9f08196554984d79af38c23411340fa7092a2ad6
29131 F20101130_AABIEI barron_m_Page_038.jp2
4401cd53528d4921e25c3d5ba05eb14b
2113aa15f6de007807c1c8e3383b1783020a9009
22071 F20101130_AABHZD barron_m_Page_020.QC.jpg
b86f57c5bd501f6d93c09fad3154b839
42e379d5936e6336198913a66a08decec30b969e
110777 F20101130_AABIDV barron_m_Page_022.jp2
05267eb5d266815b5646f23d7bc2de42
92005591fb659f613e677596080e24753a24450c
1054428 F20101130_AABHYP barron_m_Page_058.tif
5c2f12550d4a8b2bb2a913b999f17a69
56d35da41640a4d610d3c65966c215a969896172
30194 F20101130_AABIEJ barron_m_Page_039.jp2
60de67ff0226b5b809ab0dc88746521d
37d8fb7f345b691e3e3bc1f1f95995afaf43737e
95354 F20101130_AABHZE barron_m_Page_008.jpg
1f708f14efe3fd1e5cd89eb496c2f078
12c5570c24c9a72d5f323cf3ca64f210b44133b8
112094 F20101130_AABIDW barron_m_Page_023.jp2
6bdb2296b53042747306e0e9c6cead40
b2bb933f15ded3fa4712f4305344bf0fa5bb9d8a
30624 F20101130_AABHYQ barron_m_Page_044.jp2
1e5b0b8101056912a74334a52fb01dde
52f893c99a03ff7508973bf70b24fbdebd3841d0
33299 F20101130_AABIEK barron_m_Page_041.jp2
8f8a4defc0e3124c5f93d0a9abc0f3f0
f39e8e8af3046c7f55e9e2ea234b1576f60be34e
3123 F20101130_AABHZF barron_m_Page_041thm.jpg
a268f878c8d9a1cc91a1ac94a3cdb2f6
1e0a89d7d8ff0259fdee677656b19f21934e3341
95365 F20101130_AABIDX barron_m_Page_025.jp2
f9f4f9b649517ae8d7c143e62324c7b2
882260fcfb265abbf66f0a8e48f8c1af53a3ff82
9179 F20101130_AABHYR barron_m_Page_045.pro
045b9f2ee29471ed128a6651364c8bf1
a4ae45d10005126ba67b4eda4662578a48934ef6
30340 F20101130_AABIEL barron_m_Page_042.jp2
d78c8974f66c4a21801cfab254f38800
3fe1c989b578ac4fb48eed91b81b71ee2296715e
8367 F20101130_AABHZG barron_m_Page_024.QC.jpg
bf1ff40f719d2c6ad77feb1059521ddb
dcd37fc6e967e788a331651755a1161a5da16e8d
101774 F20101130_AABIDY barron_m_Page_026.jp2
3d8129c7afaf3e1cfe9ca63145d6f48b
de8c5f63284a27434450df48378a962401ef36d9
2462 F20101130_AABHYS barron_m_Page_086thm.jpg
7bf356f53a87af362a9367184c8b945f
6cb8727acfa9f662f9a1c099fe9e4725bfb8dd95
107627 F20101130_AABIFA barron_m_Page_063.jp2
a81a20764a61841a7ecd3b4c8ac8264c
2be900ecacfacf614a6dc285c055a4fc6c5e394e
29293 F20101130_AABIEM barron_m_Page_046.jp2
ce140b0b6db6ebad2d518bdfcd5ee723
a9e89cea26589eeb8c888755afb70ba0110f0962
162371 F20101130_AABHZH UFE0010801_00001.xml
5f3fa02ef53d5b85195a32c349c90316
5603cc2e170b7b77a9e169a155defd8bb1fa9262
116314 F20101130_AABIDZ barron_m_Page_027.jp2
febb45aa5361e1c3da18494b6c04b2cd
8c5c0715c428facc1bd0dc1399f135afb082f3d2
95351 F20101130_AABIFB barron_m_Page_064.jp2
c945a7dd14c114585c990b1930348313
73f8ab362ddb9fb83fcab76ad9e6c35d696d2251
29027 F20101130_AABIEN barron_m_Page_049.jp2
9021ab1232a36081e35bcfd07a61273c
6cca6c626720cb903860fb448fd02731ba26b7e5
F20101130_AABHYT barron_m_Page_063.tif
78f1f52d2e3c738abcde40bea65b6265
29459b59e9fcefd8b2904dcd686d10d34c5e839d
99898 F20101130_AABIFC barron_m_Page_065.jp2
59c3340e20c87b0ec1e637c866c312c1
48c9abdb1e92b2b1eeaf46a37e07c1f7cecfd773
31271 F20101130_AABIEO barron_m_Page_050.jp2
f6b9e8f45d2d2175e9ec4c73117d88fb
5ee50309e44caa8a77e021101c68630c84fc7ac8
111829 F20101130_AABHYU barron_m_Page_062.jp2
d8355419eec4dea80f4454408929133f
f53eee60370232e7f3613b082a8b350187f43a3f
108899 F20101130_AABIFD barron_m_Page_066.jp2
4524c1b49e51054d2876f359e50a98a4
a77965579e8e352366008eb46d505c0c7ce72b93
29381 F20101130_AABIEP barron_m_Page_051.jp2
800f250f0d0debb21e77c83012c6dc73
6e3da1df80b16de1266e39f3d09872e181b8849b
10545 F20101130_AABHZK barron_m_Page_002.jpg
461c7b12d5396cdaf22bc4c4c668e45d
33d1d43b1d7cd9e62fe6972d6301f52cd8270b95
1035 F20101130_AABHYV barron_m_Page_072.txt
1fd25cca1a946ffeffe81c01ebf71f5a
2b2c762f87ced3c16be7705cdd8735a8446538b2
108260 F20101130_AABIFE barron_m_Page_067.jp2
39ab82b545f828d5f9efe8f562e3954a
b3df1b12701b10de443afb8b7cf895849684faa8
30649 F20101130_AABIEQ barron_m_Page_052.jp2
4c9ea72e6644f5595fa1443ae89d76d6
b93b97a7f79c45d303dda7bd7c8dba22d64de1eb
56565 F20101130_AABHZL barron_m_Page_003.jpg
2a3f43263f33a482764a8ec07a5dc556
8a9ef5f8093309e6159a18573856252ed88ae339
66675 F20101130_AABHYW barron_m_Page_006.pro
016d2df7865567f589c5dc27f1186e13
293699c7e6f5578284b98f6a714cf46848c3fea3
108015 F20101130_AABIFF barron_m_Page_068.jp2
3f85e3ba93f7bb36e5a0c25a09a4fc1d
b732cfa70596259212da53c2e057cee40bc2c32a
28709 F20101130_AABIER barron_m_Page_053.jp2
81941c8be37e41318771ad3f4b48424c
ca402110f91f1fd49a81ebc418175aebd7c39b15
68235 F20101130_AABHZM barron_m_Page_004.jpg
42f7d648dd4bd1df71c829316fbfc651
f7aafde0a828449ffa98db63e569ed6bb91f2742
25910 F20101130_AABHYX barron_m_Page_084.pro
20ff7c52acf5fa476a90930d23fa7cdc
afd018eee530da6164ac52144770fd705b037167
109307 F20101130_AABIFG barron_m_Page_069.jp2
50f103dfa0259608039338d24a826249
44eb4c498a09dcafc70805a1ce9e704f404ad914
29652 F20101130_AABIES barron_m_Page_054.jp2
2c853b8f73aefc0f0388e737b5960242
454b6d4081c468a55e766af8c56f1bdea41d2f5b
7724 F20101130_AABHYY barron_m_Page_059.QC.jpg
37d847632de1971de590fd1e7de1cd4b
bcdfe49c3f27e7831fe2f48c85671058c35f0cd2
12556 F20101130_AABIFH barron_m_Page_070.jp2
a475ee937dff13a7f37977a184d218f6
4136de53e4bde3d9435c24d593ca356ad8a4f1e5
54377 F20101130_AABIET barron_m_Page_055.jp2
ca0fca06656af27d521d2ff078c87693
c717918ed95dfcd7abbfebcdcb8d40255e100272
26790 F20101130_AABHZN barron_m_Page_005.jpg
e4667c63a950d81caeb8ec322155a96e
4901d0149f62f316fbfe2140ff681e87cf69084d
67782 F20101130_AABHYZ barron_m_Page_020.jpg
1fe90e6ad2907195a31718f7beddc716
2e696bf9d09e37defb9b8035344fbcbff1f60d9a
69984 F20101130_AABIFI barron_m_Page_071.jp2
c46667f32310377f5d21111d41fc34b6
3682a40c1c0e1948a4b0c6556197a4d11485d3a6
69167 F20101130_AABIEU barron_m_Page_056.jp2
ec6c568740b29b400857aca7fbba8c5e
88852bbd2b49acf02ea8737926f8adf3e548cf1f
85600 F20101130_AABHZO barron_m_Page_006.jpg
1348d3d11d136fbc935c175cb49f4afb
deb08ebe6878b60cd29b6dd39f4e506b4288935b
40167 F20101130_AABIFJ barron_m_Page_073.jp2
b2c9d9370e04c1e2f73bfb9cea29dbd8
9e0bd52d0e93d6008e910107de139d0cd7ca8562
66847 F20101130_AABIEV barron_m_Page_057.jp2
08ae58e4b8c3419ec372aa22ecaa7cbd
d428a4d3985cfba8cc66f4697db6c2b7f7802dbb
45275 F20101130_AABHZP barron_m_Page_007.jpg
a4ef2b67fc041c3a39143b0389a8cd8e
b84ce054cf5752c5e6c6e325b25fe71ab978eaf1
40505 F20101130_AABIFK barron_m_Page_074.jp2
53179a570d6de76f340fec7493639a48
bf4b67f3d4b49ed7be033a67501e744092f5c6d5
52067 F20101130_AABIEW barron_m_Page_058.jp2
abec911baf9f9c65b71001d7eacc8856
7abeaad68fc589ce9f3bad4f2cd390486b9fce32
120227 F20101130_AABHZQ barron_m_Page_009.jpg
fa46f13ba83b52d491dee8086b85e8ba
1a4247d9eb49978ebf43d21e27c3abba4efe63db
99155 F20101130_AABIFL barron_m_Page_075.jp2
7bc8abf47957133f20c4fa407be13bb9
b07a1f782f8a347a7d975f215879ceeb921cb5f7
52862 F20101130_AABIEX barron_m_Page_059.jp2
ed33fbd5bd29391c05fec2bb67c7e4a5
3f63cb74f721ff141649632aa7b05bebaf13d291
110116 F20101130_AABHZR barron_m_Page_010.jpg
e22c2f3ec8aae73e34f9685c95559527
0e1e350b66d475dec002e15dd77793b9f3fd6378
34197 F20101130_AABIGA barron_m_Page_093.jp2
9d6534a8a7d50a1ee2ae96c6c634a945
7e7d3564a0e0922d5ee87e68a20dd1c239376b09
107841 F20101130_AABIFM barron_m_Page_076.jp2
cd00f5ef0aa5338ce6e8c6b94e4eee8a
d1dfc6a4118a3fbf85c5d76ed763213921882ecd
98406 F20101130_AABIEY barron_m_Page_060.jp2
343bb2d3f2585f78554a4a82e92709e6
e307b8c379b1fd49ea8d9463ff52db2c56908f6c
31473 F20101130_AABHZS barron_m_Page_011.jpg
3229c529c76766484f4928ca5fa37b85
e923a958018d99460d5b5f405b2458bb13ee74d4
29480 F20101130_AABIGB barron_m_Page_094.jp2
403d0558c56e21d25f8280763443cb28
06754a1bf5a3b63bf3964e31669f84d7338911da
113183 F20101130_AABIFN barron_m_Page_077.jp2
ae886817b2eab37902c534860b33ad28
9414a4f2f06524a9f823ec03ca0f0f370a32ec49
106396 F20101130_AABIEZ barron_m_Page_061.jp2
27b2ca23f60865bec7e17932c91c6ee1
7610662953a228eb0bf91306137f25508176a662
60646 F20101130_AABHZT barron_m_Page_012.jpg
ab135463539dfc16a79c93eb62b38765
b9f100b0a91599f64e3fea68233267c817e2ca3b
29704 F20101130_AABIGC barron_m_Page_096.jp2
dfe79d7fbdd3aaf4a70f236651c479ee
ec04553da247d105128e6774505f3956674f9c3a
100485 F20101130_AABIFO barron_m_Page_078.jp2
a68afe6cfef39f584e61543efbf05ecb
31e9e98201ab4a6980dc3a89037915f1111bd63c
28929 F20101130_AABIGD barron_m_Page_097.jp2
d391153beab5c5db0e3d5da1e0a7dc04
1efdaf2ef698a3c2693f6db880fca9a2e65bde97
107153 F20101130_AABIFP barron_m_Page_079.jp2
91f9e7e58a782a502d4dcb1787b54f5a
7021bc03462a26758079c441ede2b163742de53f
66200 F20101130_AABHZU barron_m_Page_014.jpg
f03dcca35a5ce819196a1aa6a2176599
884235e0eb70ee4b79d023f1b1a2c254f3fd6bf2
29514 F20101130_AABIGE barron_m_Page_099.jp2
e53656e24a09d900e66b723109fafd09
bc9651b7c19b87b6555aadd4dbc2d00a25080580
112555 F20101130_AABIFQ barron_m_Page_080.jp2
0035e7e5f28f844c12efcbdc0ab44761
a91610bcd475759d5ea63c4b401069c27b8e3ea2
73156 F20101130_AABHZV barron_m_Page_015.jpg
0120ce9a476fe204f30d09e9680be7cf
48d894673804f14c01e1c974fd59c14300cd1c92
30066 F20101130_AABIGF barron_m_Page_101.jp2
2c91bb408f476d7284bb59b6652b57ef
4d389d79c54611e1445b4655d2f15e5d6c43e297
110167 F20101130_AABIFR barron_m_Page_081.jp2
7786b0629ffe8262e4c98b2c8ee40d6d
0a958e089ccaabe0b2b0be9f8ea2d56b52674f13
74783 F20101130_AABHZW barron_m_Page_016.jpg
f9bea5f1ca90937a40abaa1a709136c0
bf8f23db35e4387418b7c49a03f447dc463d09d6
30428 F20101130_AABIGG barron_m_Page_102.jp2
f1e5b4cfbeb7b262eece20c7e2679913
8b8f458a868925cc545e42a9fc39c59c31394b93
111040 F20101130_AABIFS barron_m_Page_082.jp2
c5f47bd967f71ab2f401ecc0b7cdd5bd
dbce301fc1b3f625ef79fd6f07f9b9011740d6df
73735 F20101130_AABHZX barron_m_Page_018.jpg
67d0c1fc780eec90b86040ad08d27069
3baf0e74639ca2842c2de912cabaa0a0e04a6830
30778 F20101130_AABIGH barron_m_Page_103.jp2
58fda5b8af0f36569706657e40b4fbbe
9cb52bfd3d1f887963a727f20a3628299c3af8ad
18969 F20101130_AABIFT barron_m_Page_083.jp2
86fec74014954038975ba4982a9f963e
7391751a8a2df9d46beca507cf6a6138c0c2a425
71258 F20101130_AABHZY barron_m_Page_019.jpg
d5ea6b1e576ce88eaa6ae3c82c840602
b3984fe7ba91084dfcb555c94f8f668444e70ec9
107910 F20101130_AABIGI barron_m_Page_104.jp2
0ad83c1da0c2957497a4ee6acd2ddf69
fb0796c69c982bcb7d4085ee415b6361191f49dd
46489 F20101130_AABIFU barron_m_Page_085.jp2
b14f1172e17bccb8d0e91ff9c8fbb06f
42825ca6f54fa7cbf2109b88f1429ca5dc07fd9d
72692 F20101130_AABHZZ barron_m_Page_021.jpg
79ea39eecead5be96731a99e76ec2fff
ffe29e8f59881191802e54c3bb7bda2f9f21eb98
126858 F20101130_AABIGJ barron_m_Page_105.jp2
9c67f91f03043886327a0c30ea1a580a
25d63a7a6eef87752f45af307a68a44add8c019b
38276 F20101130_AABIFV barron_m_Page_086.jp2
0b8503c331fe47d368ae93c805ab2b98
6bb9b6446ad6f3fe349891fa9d8324bdeeaa47f8
41934 F20101130_AABIFW barron_m_Page_087.jp2
28b70834015222f8d79859865d8454ed
b835e1ad231f16523c6aaa336cbc51b394226f2d
131547 F20101130_AABIGK barron_m_Page_106.jp2
584b0ffe68ff13978e76814385cb879a
c94aa50fb1e9442b7d5b06e3b896433a709f20cf
94038 F20101130_AABIFX barron_m_Page_088.jp2
bdb534bc3d4c8ab66ff8ee1c2f8527ee
b50936589ed6c88421f442abac8e2a17c3f8a3fe
F20101130_AABIHA barron_m_Page_017.tif
71f2a57769e6045809fae39ed3c05b39
ec2a5aed2b2aa80f97661f44418484fc94d4db17
107449 F20101130_AABIGL barron_m_Page_107.jp2
6230758669d2cc3c12389aad90c6b40d
b5d7b0168e2ca25faf0f89fa6c1bd42ebb2a6fb7
109722 F20101130_AABIFY barron_m_Page_091.jp2
a91f226a0e61f155b873ba7f34cb39a9
f83733a7384df6b915237e9fa76f8ff02a33034c
39980 F20101130_AABIGM barron_m_Page_108.jp2
402827c8b2ebbf18e8de5ce3fbf27f76
44a47502acd48e51044ca79c01211bdd3845e239
21221 F20101130_AABIFZ barron_m_Page_092.jp2
226ee52835d686502a66014cb4d2b448
06c0b535fa23b422cb03ec04965b40a1e199bf5b
F20101130_AABIHB barron_m_Page_018.tif
7b49f943d39714aac2953df592cf0387
cb5755b590874239c4b2301789daf9fc681db4b3
F20101130_AABIGN barron_m_Page_001.tif
e755448aae5a68bbfa5743f71de8f443
440fcfe8cf020c3e9e529f9f80265bf558c23cb5
F20101130_AABIHC barron_m_Page_019.tif
2e974ceb5aa16a0eea8317531fefb581
db89908885b1f9c448728a4903159bf22c90573d
F20101130_AABIGO barron_m_Page_002.tif
25822ccb4b06e8d7972e7c37b39238e4
88c4b0ccec6fbb2b56a9d8efc01750d88337b781
F20101130_AABIHD barron_m_Page_020.tif
af874ff735836bd7d9c0f87991ab2822
c3584042c289ec1609cf9aab9312c8e1bae80b9c
F20101130_AABIGP barron_m_Page_003.tif
1dce3610139732308d82fd680cb33b29
4f2baa1da26506be66921a0aaaacafe2a41344eb
F20101130_AABIHE barron_m_Page_021.tif
7bbb2eb713ba197e42add0c24be4c55c
459e0e9b566c84edb89126fd9f2a8362f23e0f9f
F20101130_AABIGQ barron_m_Page_004.tif
b5d2a4dc8ce1d739f09943811c437503
a4e32572f02f7d2319fa6401d8f4dd8dc080fb7b
F20101130_AABIHF barron_m_Page_022.tif
5487d0b3399d30eca38e2b99fb80ae98
9c38f6855beb3612e3d92d0d2b7a078c6f7ea887
F20101130_AABIGR barron_m_Page_005.tif
c32d25a11a3aeefdfceb2e1dc4f47883
36a8dd5dd8f05cd5fa7a9a25aca4658388110399
F20101130_AABIHG barron_m_Page_023.tif
8a72901fac7155e08cefe459a82bc46a
4d7f824e67671ef79a0f439e91adee10f16d2fb0
F20101130_AABIGS barron_m_Page_006.tif
b85970f37d1fa451686e065161989d0e
127b699e850c57549290b6ab7be2f74013afdf94
F20101130_AABIHH barron_m_Page_024.tif
4120329d0c1aa54002de70e116089642
47d25a72c047807257d11c3ee4cb0543d940a239
F20101130_AABIGT barron_m_Page_007.tif
013d06c020e27e1904cdddeb62b4c32b
c08eea004ff4f07941fbba3e97cb68f129531d4a
F20101130_AABIHI barron_m_Page_025.tif
5eb1cbff44106875ad4ab36348751abf
beddaeb8468bc8f6f9cf41942efb1cacdad02e52
F20101130_AABIGU barron_m_Page_008.tif
7553bb67c975e994efb4ded4f0c248fd
520344968e8a2a7c45cc664754091fac0e6a195c
F20101130_AABIHJ barron_m_Page_026.tif
909f47fc2391876f4dbed161bb9e7c23
db2898adb4c760adf6f65b2f27cb706032ea2272
F20101130_AABIGV barron_m_Page_009.tif
7c023f7c6a2ff2235a3c7239bbbf3f86
47dcedc0801321ab6af5c194d1bf4327d4b1d7f1
F20101130_AABIHK barron_m_Page_027.tif
1b82b439493fda3cb7f034b4462a4b79
cf9df9b4d47e2326faa6e87dc9ccd41e8ce306d1
F20101130_AABIGW barron_m_Page_011.tif
b663a79fa8ed741f7eb811a7a6c56838
75d6786f9144059a091cef5278e0e3f24a3ccd89
F20101130_AABIIA barron_m_Page_045.tif
278ddbe18ae7dc0786a8e33346917ba1
36260a8b469f9a00ba0806e440acc51026a71676
F20101130_AABIHL barron_m_Page_028.tif
cccaa431a546d0264261f75f9ddf0197
bcd710550fedab832a20bf436d970fafd4852a33
F20101130_AABIGX barron_m_Page_012.tif
f9cb0e483f87e8e12c72733d4ef899dd
7106738e19427f8911b6e36887fad6e494ec37d7
F20101130_AABIIB barron_m_Page_046.tif
4e6680fcf2aac1b8a5640c9d515c1851
2cf9cd5892d627ca73f2503ccccdc99f9aa7e48b
F20101130_AABIHM barron_m_Page_029.tif
417af53d1b1e77d5ad233934e5fcc403
b3827c5887971b70cd187748a1b59c00590980bb
F20101130_AABIGY barron_m_Page_013.tif
c7a674e80a641e52933a8c1a77e633f2
064441f0cbef58e7d812f28ccf13ef9ede994a39
F20101130_AABIHN barron_m_Page_030.tif
f0e7614cc10147fe3ef021a2dc1d8f17
9550b781484fa7732929e5baafce818cd92d2a2a
F20101130_AABIGZ barron_m_Page_014.tif
0b755a0f8f6a219e8ce5d658d193cb02
adad30441cb0a19c5d99c30a3d829d4a059ea34f
F20101130_AABIIC barron_m_Page_047.tif
c34d19739abbbc713171c8b7957c14a5
2c80ec451ee3bcd88c871a4a8c5b2072bf35c7a8
F20101130_AABIHO barron_m_Page_031.tif
6841c6c47a076bac590c88e183c124fc
668b087ac91ae0c8fb01a08beba6996720853874
F20101130_AABIID barron_m_Page_048.tif
87d10dba46c6d4ee8fac13c44af7c417
8a253e5b231300a6da1d0634728d7ca9d476dc90
F20101130_AABIHP barron_m_Page_032.tif
58f9206cbe0d4c965960ca7834ad3d80
f37b6752ffb1650059cf1b14a44a02f0ac8ea4ef
F20101130_AABIIE barron_m_Page_049.tif
3cdde3a7aff9ac4578e8f89cd19584a9
77df2af7786b81409b819bb60ea1ef0684403e12
F20101130_AABIHQ barron_m_Page_033.tif
c28c4c3464e11cf2d50fa4f420863cc6
4dd96a74d17af81a910999755863a5a3fed8c118
F20101130_AABIIF barron_m_Page_050.tif
43bf2a5d44f94551761c79d1bdde3ea3
8fd3b0cf57377c7a723efa7dae27c04ae5f5e3f6
F20101130_AABIHR barron_m_Page_034.tif
51e1a2301cb25ed8b65436632dfc3385
d374c57a144b6e8b7f0d1d0c79e9cf4b168ee2d3
F20101130_AABIIG barron_m_Page_051.tif
8d3628e5685ecdb5ff612fc3e063c072
6e6ad4f85108220effeb95088af89458a1d5d64e
F20101130_AABIHS barron_m_Page_037.tif
2ea62feee2f8c0976fc70495cd182e8f
8a9ee90453873c8705541455e242e8895d8586ff
F20101130_AABIIH barron_m_Page_052.tif
dacc4651644df5b57c9a14655ee26893
888525d2a1b44be8709db8bad2e5421ff5b4abcd
F20101130_AABIHT barron_m_Page_038.tif
ea1ae7758bbd9fa9a92c4f7c1a925979
70b1e3a130d8074d8aeebd7a14350ae8bb49796d
F20101130_AABIII barron_m_Page_053.tif
4900a8471516cda96bcd4a5cf9fba38b
6745d97201c6c48a0451ba3876c33b9aa3cc33fd
F20101130_AABIHU barron_m_Page_039.tif
f99a82ff688fe2d6ffb1786afcb45939
7fa2b306fa4d5e424b0b754e08c1826e0a84f0a4
F20101130_AABIIJ barron_m_Page_054.tif
0dc615429b0e1afc11ed924e6ef359e1
fe58010227a49a524aa01083f81dcd253db92afa
F20101130_AABIHV barron_m_Page_040.tif
98859c848d643b2d1925bd57e1ace562
7fea292f111fb7e66f9d7634baf9dc414c4b8716
F20101130_AABIIK barron_m_Page_055.tif
a803cc4fe5535ff7bf316f39ce611f18
87ea10bcba96b6588f1ecdb9d4b43b165bf8b87f
F20101130_AABIHW barron_m_Page_041.tif
c30257099b6d6748db3e93fe33c612c9
c4a46935964a06225f6a846dee94f222f1374d35
F20101130_AABIIL barron_m_Page_056.tif
5e3da4fe6941fb5755e70025a0942743
97769167d3caf1eedb50d1a370df4571c81c07d5
F20101130_AABIHX barron_m_Page_042.tif
c25616bc1340bfd7335dadb38fab049c
fda2fd47dfbd00ec365d377cdc6f6ea182570eb2
F20101130_AABIJA barron_m_Page_075.tif
ccecde58c63c5b04312df3830019d5e3
34a271016a13faed17e6a55751bbbff5751e2929
F20101130_AABIIM barron_m_Page_057.tif
0505b7b0c80bc7385aace96fe82097c0
b4c08bd35ce6b290f7f7a2988fdf81af7b423fd5
F20101130_AABIHY barron_m_Page_043.tif
2cd6c7dca1fe967323f57960f47075db
c6df0b9ac644c3ce368118da42f9c2dcfc4c29c0
F20101130_AABIJB barron_m_Page_076.tif
14fc2857be61a4d96de2bf44056a80e2
52eef02e046c9dd0b94423a20344b35dc6abc91e
F20101130_AABIIN barron_m_Page_059.tif
b557e1be01c1b2c879d6bcda701cbd47
5a190aafceef34a9f5def0b303600d6e49b89ba8
F20101130_AABIHZ barron_m_Page_044.tif
004d9c4d97b2bd38d59884acb6637b4a
e70784a29fb85607639a4bc1b0edad8aed3fc39c
F20101130_AABIJC barron_m_Page_077.tif
dc9974ce08cadd98bde6f837341ad336
cce42e9d9deeff818f4a84aafc26b7f73b1a4480
F20101130_AABIIO barron_m_Page_060.tif
0ec1088030c2e4167483a483ef7cc8d4
257a730891ff71987918a77ecde470e92b3a6ae0
F20101130_AABIIP barron_m_Page_061.tif
e9ad5843da6793db0f660139eb1f418e
cd960399c28e6cd5ca100f211ee7ef8e669aaa8f
F20101130_AABIJD barron_m_Page_078.tif
a99f10c3f6273747dda10ea591db4fc0
51608762736017b45736f2e3739f2faf5bc3769a
F20101130_AABIIQ barron_m_Page_062.tif
d5687697d3c5adf732c2351b80f8db64
c53c5eeed51a591a6614730f3a38840ea61d7353
F20101130_AABIJE barron_m_Page_079.tif
fa0c62ec410e6fef3e6e7548a70e7193
136faa10f16bfcd7dd54fd4745d4febce3b56d01
F20101130_AABIIR barron_m_Page_064.tif
5644986c01e407f10d0466c69ce908c0
37467c4f17eea4c0723dfc5280ea59073c35d172
F20101130_AABIJF barron_m_Page_080.tif
8a88857b2843b086a8266ff50476b6a7
47e48e75a92fc251e5082b3b7c7110f800a563bc
F20101130_AABIIS barron_m_Page_065.tif
ca78ca7e47ecc54dd5bbadf68ebe882e
3b76092bc922837f7c435c3166f5502eb39db1a7
F20101130_AABIJG barron_m_Page_081.tif
8ac013271b2a3dde67b8dff419994f14
c69a032f96eb0725372f403ecdad89457a9e1e95
F20101130_AABIIT barron_m_Page_066.tif
df5115c11002aaa46d7e86648e3e305a
b16b4b2d275c1085f61b92a19ba08c246d8e62a8
F20101130_AABIJH barron_m_Page_082.tif
d1557a6ecd214e994af98dd9cf4238a2
7b6cdf664652802daa6b84317ad4ac7fe4c20a73
F20101130_AABIIU barron_m_Page_068.tif
37030d68606f0b3d122f2b5afb6ec2b8
456cba6661eefd6c89b6ad34e7fd3feec6faf67a
F20101130_AABIJI barron_m_Page_083.tif
526deca287ccc11852f9d4c56a9c9453
5cfafce56ede831b40bf5dc51d3b428df42366b7
F20101130_AABIIV barron_m_Page_069.tif
01c15d0bf2d87407acc1bd2c60a7668f
168c7a61e16e2131101db35c85fd71f881a2fae3
F20101130_AABIJJ barron_m_Page_085.tif
d793b8db08a4b8781a7c2a14c7a09d8e
f44b04524570922118ce87560a2233cc9bd57c47
F20101130_AABIIW barron_m_Page_070.tif
bbe2edac053ceeb15d6f81e63a28dd6e
2c27f0066cd535831bfce8a9a912d78b17c165e3
F20101130_AABIJK barron_m_Page_086.tif
31228f72f6118a1182d46cff0d6c9e4f
61d389a914eb2fd3f20a1e302195f403e4165092
F20101130_AABIIX barron_m_Page_071.tif
3e5935741ba71f7f3eaeee751a14b545
680f2e394811bba807740ce12b722547cac9b755
F20101130_AABIKA barron_m_Page_102.tif
bf9386e3c529fbece84fa350fa233d03
a865e185fb7aa23bbd0c132164d851090e1f5ecd
F20101130_AABIJL barron_m_Page_087.tif
085bf869ce311c8624ddcec6c839230e
824d4a7bfa2001f56e003089144fdba908283ea7
F20101130_AABIIY barron_m_Page_073.tif
83c836aa2109584ae45701892f33716d
47a2ee4959c936ec406a6c2eb59215698ab116bb
F20101130_AABIKB barron_m_Page_103.tif
dea7e09c68a0be7510d81882f0948f1e
98dfbccfcff17f1173b0ad55d74a97b8468afca3
F20101130_AABIJM barron_m_Page_088.tif
47003d8c5898af7c055531c043da7687
1c730c402ba7c194ce57eae390a50e8f818d988e
F20101130_AABIIZ barron_m_Page_074.tif
81488af7f04107a9005cdf793f95d3de
c18215151c6a15c29d942647b9e944e38cea7246
F20101130_AABIKC barron_m_Page_104.tif
d2d3350887415b9a4b26d12155c3fcdd
8a1b7d8b805e5365c9b7461b602fa4f70e9d70cf
F20101130_AABIJN barron_m_Page_089.tif
098f232d495dbdd2201e8723477f5f7d
c86fc177c02bdfcb693732b257a07873106573a1
F20101130_AABIKD barron_m_Page_105.tif
4edfc02c0671f555485947bfb6d03bce
987a1a004cad1f43eb0c3fbbaab72b21daeb9548
F20101130_AABIJO barron_m_Page_090.tif
9132bef2f1735f23e6e7f2ea0ba22cda
05b186dd339e74ce09096fb12634b235142bc9bb
F20101130_AABIJP barron_m_Page_091.tif
154d179378bbcd72a3d8b6a38dfeceb7
d4e2bbbdac9206d0165933bd7e33465f9e0e5e0c
F20101130_AABIKE barron_m_Page_106.tif
a2fc2e511ab4b0781958e06ddb39a405
523091d540909e6e184bf5fdaf3ed8fdbb99f023
F20101130_AABIJQ barron_m_Page_092.tif
b93f500f6fb7ff159addc52338a6e154
8eee4f86940e872528423ce28a9ad8186ad37160
F20101130_AABIKF barron_m_Page_107.tif
9ef833becfd9916097477c450a56f461
7d932552bd3ab9df400bb9c7f2e69cfc08faaa2a
F20101130_AABIJR barron_m_Page_093.tif
29356ffa93b4a7fd847c76d8b2a338c8
3c17d1668d12cf9d61bd9a065bdc1fa21043a453
F20101130_AABIKG barron_m_Page_108.tif
57223150eaf6a797f7ba041cf9c1f5c4
890d96e8f3f72a4e21d6680f8afa41829b63e96e
F20101130_AABIJS barron_m_Page_094.tif
119f2f1e7b06f46ecd7d4e2917a13e07
81e45281b8276964331e149d2da80d62e6ad59f1
8644 F20101130_AABIKH barron_m_Page_001.pro
04d714d6d7f247b74ef60cb023bf7adb
2d431d2d8a76a38eb15822d42372e856155f2b08
F20101130_AABIJT barron_m_Page_095.tif
7a705d71b4d90ec8800ed44b09c3e74e
567b635be5a59b74bd7944171803efc17e42ea09
1331 F20101130_AABIKI barron_m_Page_002.pro
dfccaebbb88e4cb6d09230f9cfe7e41d
bb1ca1caf6f924a1cd4fc194dee7790182ec02ae
F20101130_AABIJU barron_m_Page_096.tif
caf1037d010c4c12312eb55299e79873
ac8e12402e5780075d56a86960ba7ababbbdc8b2
37031 F20101130_AABIKJ barron_m_Page_003.pro
23e9da870b5bdbf57308ae8be9c8df10
dd9afd51d805bbcde70d710c6985fd83d0f61476
F20101130_AABIJV barron_m_Page_097.tif
9597ffbc0962d996f34807e9a11f74b6
b3014009365e94b5921890e7d494b56667b00e01
66642 F20101130_AABIKK barron_m_Page_004.pro
52101b67ab842746aea891e33cf5b00b
ec75d9ae5f1c950193274ce4124fd52aa0341570
F20101130_AABIJW barron_m_Page_098.tif
810300930d78f7b0ea809498d8b3c139
213525f5534f32462c6e95062ff5cedf6d596b9a
50320 F20101130_AABILA barron_m_Page_022.pro
5bd924b299b47a1e4ea4e119c058f276
e942b6d6c4f02a06f8bb05e51e8b1355c91d9403
26633 F20101130_AABIKL barron_m_Page_007.pro
ec27335aacad61fb19a3425d8e04656c
5dac26219394056623a084ab5c4b34c22721a569
F20101130_AABIJX barron_m_Page_099.tif
8f027c1f1caff61eed126a8855dd1ad1
b0a5f9ad09b7f7d1780b1a2906f7a5afcdf4d441
13344 F20101130_AABILB barron_m_Page_024.pro
f69db2db7d5721a449032bb5227e2566
42924a765eae3a2cb4a7a9be0e5bfa701650d74a
63495 F20101130_AABIKM barron_m_Page_008.pro
7cd8c78ea492149a7b8569224ecffb9a
8991a98b70ed26366baf641d0e0fcbd9283c030b
F20101130_AABIJY barron_m_Page_100.tif
4f850bb91d4a80fd414559b7015374e1
b5d537e2c9638134b2078b1cf6e278e91956ef6c
43002 F20101130_AABILC barron_m_Page_025.pro
6f1f3e28def3e5d64cf790e651709210
f13b74450ef7f49c674813d918b992418dd4a0d9
79806 F20101130_AABIKN barron_m_Page_009.pro
d883affb158838b4f493f6239bd5531f
0a62dc1d5303456dd7f804c9b8d6cfacebfa2f00
F20101130_AABIJZ barron_m_Page_101.tif
5a75895cf405674734b20a7d7f194828
ad7367e590212736aa471ff445fef985af186000
47090 F20101130_AABILD barron_m_Page_026.pro
604a04daacd81b2dbe4fb1e06a485909
ec613737e0211ff615ea6df015d6cc67fa5a7091
80753 F20101130_AABIKO barron_m_Page_010.pro
22b167fb4b3fa61fcbea8d7357fde033
513e831babf2d8cc85179317349861fdb56fed2b
51745 F20101130_AABILE barron_m_Page_027.pro
c446b0c9ef96367275890663e91b4a1a
0796fd08a3a52e73569c7da210c45995592be315
18286 F20101130_AABIKP barron_m_Page_011.pro
4694da89d881f205dc83928b82aae6ef
6d52ac7c9801ee4213f3b18f40e854833cf55742
38815 F20101130_AABIKQ barron_m_Page_012.pro
98989e04cd5b64d1eedc5124bdf14b9e
dfe43cbc753db8a5709587d9236b5fd74f3fb594
47176 F20101130_AABILF barron_m_Page_028.pro
a6b411cdc2aa5b6fc2d76c005af3d2b9
6014bbca43bd31e4c87374724637b6013554f481
49275 F20101130_AABIKR barron_m_Page_013.pro
d5989b7e19ae62485145aaff4ff8b796
c446165f1bee2732168cc5c86e4d440c3194226a
49816 F20101130_AABILG barron_m_Page_029.pro
bda4dd3bf7af4416d18f21ef4073cbca
3968ce785658da1d6424c4db37f3faec082999c6
44971 F20101130_AABIKS barron_m_Page_014.pro
69021be7e06ec0c23483d380270022dc
d8902cde7fded0449000c9a26dd075a174b9c7dd
51461 F20101130_AABIKT barron_m_Page_015.pro
98b1f60afdf5d639604e0eea7de0e099
e6a6ee30db120435e3236469e7e1da8c77d2a903
50336 F20101130_AABILH barron_m_Page_030.pro
4adb6beaf5efa8fbec42db8409fbeaa9
7d4128cea081fef462a3f62091ecfa6f791ab695
52390 F20101130_AABIKU barron_m_Page_016.pro
af0960de1aa49e823c3a018daef35a28
4f9eae77754e6498c6407e577c018aa913431ced
52294 F20101130_AABILI barron_m_Page_031.pro
d5ede0ba040da228d0c7491a2582da44
bb8a606034467c5c97a7b5c5247efbd0a6f3d6d7
51465 F20101130_AABIKV barron_m_Page_017.pro
9ad499ca9367383f0c2f7ae6e36e02c3
52d811755b04394f3a2ab625f1eeb15bc8e35638
49925 F20101130_AABILJ barron_m_Page_032.pro
494c38f2a61b2abc46c2142ea024bd8e
e89a531f5819ea6ab38bf2961216f0a6519e47ed
52196 F20101130_AABIKW barron_m_Page_018.pro
37b0cbd48c98425c5492d6014e0f9752
305b2557d808248c81e0e3eb94dac37f0e6a2e92
8615 F20101130_AABILK barron_m_Page_034.pro
2166cae7c3c6b51cdec706900e9d4915
d15754634b0ba477a6e5b23338c8e2e3a5d96b00
50357 F20101130_AABIKX barron_m_Page_019.pro
5efe01ea746fe32d12082ae01e3e9ddb
f7c9f8bb443a2254cfeca8083c7d6ec2fd5f74f5
10659 F20101130_AABIMA barron_m_Page_054.pro
f64bd8805d82c79a166dd0ed0589d084
477695456030b62d20d5feeff366fd6a450918d7
9519 F20101130_AABILL barron_m_Page_035.pro
278410e97789be2894d5870695218587
fca5fb89139b2d1949dd5e8d906e3bbe0d7b251e
46650 F20101130_AABIKY barron_m_Page_020.pro
a9d84084b8e6867da570bc76850a53c4
c1788c0e279c7dcc4b030789ebc35177a597396c
23096 F20101130_AABIMB barron_m_Page_055.pro
c93fc21fd40ad55eefa490ad7da85586
42679659273143be4ca4107291b4c656992f0102
9713 F20101130_AABILM barron_m_Page_036.pro
aa8582985433fab6208fe472801d0728
50467c12134fdd07197ea589913027adfffcb572
51651 F20101130_AABIKZ barron_m_Page_021.pro
d0d4986212f67afbcc19edee62308a18
1822ae7fd7bb58e9a9c59e1e083530479aee150f
31007 F20101130_AABIMC barron_m_Page_056.pro
714add3d0d5322bf7ea162cb972468d1
d4f8a042c556608c95652841efdef2fccf1a773c
9716 F20101130_AABILN barron_m_Page_037.pro
09b0b3c52fd917ccd48ddae6bfa69692
cd80453d291a0fc85c9b257511ef83473ef0a8f0
33134 F20101130_AABIMD barron_m_Page_057.pro
2f1955568ca1a1bcd4855ffec5070edc
6d598542c4c04cffafd118232d2198cc57e52b69
9596 F20101130_AABILO barron_m_Page_039.pro
77be33d0d54dfbc57c90ad425da028ce
1f2725af5b0cfb171589025a505ed053e7c0c479
24622 F20101130_AABIME barron_m_Page_058.pro
63ed0bdd736d5b77739b66a54a1c7225
94e85a562f0f9a0ef05062c436266bb4b5d5b649
8786 F20101130_AABILP barron_m_Page_040.pro
3f4247642746be5a34770d65ada5c508
d475318a8b6b5c21973856abb662141f4e4cf7ec
25192 F20101130_AABIMF barron_m_Page_059.pro
3a268b24b8f15eb263c6fc12048622ce
6e35761f3429683934a7da10d0003ef6c464cc09
11460 F20101130_AABILQ barron_m_Page_041.pro
475af3f88cbe46e1b24d678b4ce8c81e
f0d31b8221d1cf71ce057a0503e0aef72f86ebcb
9488 F20101130_AABILR barron_m_Page_043.pro
a1ed225c7b5cde63e5f173e4b9c33796
b0039d1efb3d89bfa4212d893899c843a9ee6946
44109 F20101130_AABIMG barron_m_Page_060.pro
60d69f06970b3206626f55547af3b00c
e3923c2838ea65e5d43a10639cff4a2839f9187a
8596 F20101130_AABILS barron_m_Page_044.pro
51c3c0b6e3740c73360b55ebbb565184
6f721e01d4e8d4fb6323e6f0da14fd3c05aba0c5
48699 F20101130_AABIMH barron_m_Page_061.pro
59dbbf15b3e22c43a03bc8774199018a
d349649dab1e1c50a333e606ea1f1159f11407a7
8184 F20101130_AABILT barron_m_Page_046.pro
36d9504d91fe2d647efe72bb200722f3
0cbc089f667f20c6ded8c89eb0c8e46a72d44a80
52830 F20101130_AABIMI barron_m_Page_062.pro
842507cc37d5f0e5a4809ba7a5424ec4
37c86a4fc25cd2d5e5fa2723d441e8637c1c63e3
8504 F20101130_AABILU barron_m_Page_047.pro
535ca97e7e6dcc279e29801749aa8c0a
82d26c7438120a920a79fb297fc08b0e33734454
49444 F20101130_AABIMJ barron_m_Page_063.pro
287c8740ee1c006d99330a5c2c7310fe
523d264bc3d0a70b9b1c538820d75c961ec88709
10364 F20101130_AABILV barron_m_Page_048.pro
c45b65d8a28ceb520bac3b4feca19a90
1b7470ad59996f7104b40a9f63e6ec870333d057
43054 F20101130_AABIMK barron_m_Page_064.pro
4cf324c8673c70fea07db3c9d7e2622b
b5ae4f6ee178c898fcfe4385b684a9736561f507
11272 F20101130_AABILW barron_m_Page_050.pro
71f30010525b5dd026f30651f2db75c5
fcbc66adbac56e201fc00ee642c947ec021bbc2c
50964 F20101130_AABINA barron_m_Page_080.pro
271280279ac78d1c56b9ed28f41d2418
58e69c9e9ff453fe000dc3c67d76437d6f794358
45254 F20101130_AABIML barron_m_Page_065.pro
582ce10ed26b5936421420e78b2238bb
15e21bb0abbf7bab7b8146a2ac3cdfef7b618ae8
10485 F20101130_AABILX barron_m_Page_051.pro
c9dc320638088f79ece7e8e90ac75df6
eb81c319f222e98fd34b0f2f9615b0d44fd2f536
48378 F20101130_AABINB barron_m_Page_081.pro
f100deb62f14b8a1a06818241f25a3d5
8f1c101b00a9ede555f872d8935be6401d00e3ac
49809 F20101130_AABIMM barron_m_Page_066.pro
7917302a3cc3e368e7d92210bffdf5ca
1c04779342d1c45aeb08246a1bac9aad652edf6c
10731 F20101130_AABILY barron_m_Page_052.pro
f4afc95c24bb1a4f28a53a29640296f3
64ac44856e110f4be88668299ff90814b8700b21
50254 F20101130_AABINC barron_m_Page_082.pro
873800a42a29fef3d10c00f18b1df605
5ed8ff80178fe257161bf72f0333988a3ddc0117
49973 F20101130_AABIMN barron_m_Page_067.pro
8b192233972195bcc3835f98d406c075
5a32616a2fdce9f91a4f300c1e803ae2b0bb64d8
9368 F20101130_AABILZ barron_m_Page_053.pro
dccfb44596e8fdb0b5057c026f2406c3
3815486e327827e986c9c5fa426af69527372839
7085 F20101130_AABIND barron_m_Page_083.pro
c1cbf681b667fcfdd89fb47c8b79a281
c3d42cb3dee7d332e7c48bb3a08a73e83d71b60e
49393 F20101130_AABIMO barron_m_Page_068.pro
1cc8f879194a4a477fdda9dc1ed3a4e8
e99f7e1b4e5e4408254a3928edfae4464005aaf7
18420 F20101130_AABINE barron_m_Page_085.pro
8bc450902e0f91c8e18be8597792e5b0
d033f48bf05a232d2c77d2490fd1fc178532a366
49773 F20101130_AABIMP barron_m_Page_069.pro
9b88693552dd518fc50974546fbfb0e6
9a4f1660c1ae7429f7cb2c0f42bbcec02cbd0976
14132 F20101130_AABINF barron_m_Page_086.pro
363cff0fc5badbc6a98edf33ff5aeee7
672a0c208df649afa5b494397a1ed992c4c4a04e
4340 F20101130_AABIMQ barron_m_Page_070.pro
d3b6d69edfdc2257dc27bb451a6c6251
3ebe68c1720fb8421ffe1be3d18862463306ad61
17726 F20101130_AABING barron_m_Page_087.pro
7ab40425c7d727641f0156d434fdb5e9
608dc8a00ff3920239793cf70e1953ea0b7efd4a
42903 F20101130_AABIMR barron_m_Page_071.pro
0435474693ad40bf3bf288963071633b
f2a343b1edd53f1cb7022178ab557f76d3efc71f
21728 F20101130_AABIMS barron_m_Page_072.pro
efce7f64a28d95ce7586afbf63d4609d
615b4f7bda23729e20a24af51ba530dfbec64f59
42620 F20101130_AABINH barron_m_Page_088.pro
4161aecd38b96e70f383cc115cedb767
d168257a22c4772d4c5821545e2126b190440aa3
33869 F20101130_AABIMT barron_m_Page_073.pro
22a4fde15d870bb05c1e2e34a50002d4
82b2024228d31f1eb25849fe7c9596e8273cd07e
52622 F20101130_AABINI barron_m_Page_089.pro
0863bcaedcf50c1e374b524b615e52da
e1f264605dc2a1820e5fd081e043ba041beb45e6
34031 F20101130_AABIMU barron_m_Page_074.pro
a729e8c01350d4efe23ee8929a731aec
60ddea5ac9ceb32a71db60b9444d7a3a0584c967
49929 F20101130_AABINJ barron_m_Page_090.pro
186efede578eadd4d374a8211ec2dac8
9a583cabd67a566844ccb22096a02317713545bf
44468 F20101130_AABIMV barron_m_Page_075.pro
96456f044491a47756d4b50c5979fd9e
24d355fe7a54d515aa9b7714adabaa0ce27f5a05
50471 F20101130_AABINK barron_m_Page_091.pro
d0065069eb394eece908448424fbabbd
813b45827cf2eb3ad6d838bde592de2be9590aff
50251 F20101130_AABIMW barron_m_Page_076.pro
587429ef6ae962054ed028c43efce64a
1d64aec29426cbf508082f43e3281a31e1012a12
8452 F20101130_AABINL barron_m_Page_092.pro
b230f62aa94b1dc718c5667142dacfb9
dcd138f7057757ad7cd54fc59eded73d5fa46135
51774 F20101130_AABIMX barron_m_Page_077.pro
2987bfad1764c762d4bc1f609d675af5
db41191b55b01ca677e8b8cf7bdd97a8130f8633
16865 F20101130_AABIOA barron_m_Page_108.pro
7a97aed2dd2c52c406e4464ca1a681e4
3befa3f422097f3df798114125a84e4663b5ebb2
11293 F20101130_AABINM barron_m_Page_093.pro
b2e7f54c336fff574c90f1fa7d002e53
72122372bdb01d27aaff72c92d612e8ae442c190
45380 F20101130_AABIMY barron_m_Page_078.pro
731e07ab15b451feb04f117a637e89ba
d4847b4a6510964215f04ea137208941df4aa729
474 F20101130_AABIOB barron_m_Page_001.txt
7a311f7874bb7801538c34760d31c163
7e1b44ac7c4f152d7f5e040bbec537d7c968c2a4
13229 F20101130_AABINN barron_m_Page_094.pro
264bab5e20dc4e4a5afae78403acc53c
6099e5d9bef03784ff36a75ab2db312a6c9ea271
48626 F20101130_AABIMZ barron_m_Page_079.pro
e808a2872d2d9437c5336c091c12df04
8ffdcf7cba926e1cb44a9be762f47d340b9091fb
122 F20101130_AABIOC barron_m_Page_002.txt
8dee7e45698698d76dfe9bbf3db74880
a726b140ecc0ea71cbb3885c5000bc75b16db2a6
14919 F20101130_AABINO barron_m_Page_095.pro
e473fef9fcde3f7aae393512e1df650b
1199633d10ab6de954c6938ee4e2e3a3e216d77a
1519 F20101130_AABIOD barron_m_Page_003.txt
e9c34e3b4da44262cd02b092d061fa80
9107209031381627c570fb67ba6e17f753ce3595
12810 F20101130_AABINP barron_m_Page_096.pro
93750c1b1ba63a0464884b51d83a420b
ea6dbdc1f343641121c6dc2eb7348872385cc9f5
2723 F20101130_AABIOE barron_m_Page_004.txt
41c1717ef39d00a49ac8a4a4290daee1
0d31f735bfd3d001afe45aeed49bcdc17c23a522
8989 F20101130_AABINQ barron_m_Page_097.pro
d556ecd38dec66dfdd46eaf4bef6f3d6
f6a2a7fb61580482acaec4f4ce3a26dca66f83d4
936 F20101130_AABIOF barron_m_Page_005.txt
41d7093b67d02b01472fd843e16f03d1
87dcabbf1eac17caaa2ec628d6f78b772e30868d
11997 F20101130_AABINR barron_m_Page_098.pro
9ee071d47c4e1e2b51d13b2e985bdbf2
84cf3270cbed63276feb4887b04466ad6ee2ebdc
F20101130_AABIOG barron_m_Page_006.txt
247e0f616a1238065272556f13be1dec
90d67593d7870cf1b29ccf4e9deacfe3b613dbe1
10276 F20101130_AABINS barron_m_Page_099.pro
6de6bd7f47baf575fb6d36150a93fff3
4ba639381f6758a8accf050c3c8c9530b7299793
1083 F20101130_AABIOH barron_m_Page_007.txt
3359ce4825583360837adcff58af9304
635e4133346769907dddbae0e60f5d4e496fd73b
11010 F20101130_AABINT barron_m_Page_100.pro
3edd23c1c1ba5e3e610a4bc8d080c5fb
0150f5311dfc6a61b27cf438dc83568b235a5208
12437 F20101130_AABINU barron_m_Page_101.pro
68a8c6f51f0bf7acf7c003a461c6fb72
d5d6e978c068325a8f43d8dd728bd6cc36b04654
2609 F20101130_AABIOI barron_m_Page_008.txt
aebf12e8d36ee210089d96d5b2d08680
f2774dbc7c139ddd2334a72978ca94ecded3e598
11990 F20101130_AABINV barron_m_Page_102.pro
cd10b1bf662833dbd777543840b7abe1
e505a962430bf5eaa8580751e6edffedaa2f8490
3205 F20101130_AABIOJ barron_m_Page_009.txt
c6002b36d3fbff4eb3269a224658f43e
64f11077db4a5c226d64d3d4816feb3c35bba0db
12751 F20101130_AABINW barron_m_Page_103.pro
39d8202b200b44943e204554266a0af4
04bee1d9db3547124c902629a7bc7c51f9281aed
3258 F20101130_AABIOK barron_m_Page_010.txt
c954709d867d373197d80c12944a6668
32972da4f85ccd8f0bf7d6fbca46715c3e24a79e
60973 F20101130_AABINX barron_m_Page_105.pro
0dbe1bbdb13628f35083bd9d3be06f1f
4a77130e94875bc8656de18f71afe670ae6e3f8f
2035 F20101130_AABIPA barron_m_Page_027.txt
1dd308e1ad98f0f3a40d9e5f7aace55e
5db86c37f07c94d445200a54e818d92af307d5a7
750 F20101130_AABIOL barron_m_Page_011.txt
eca8c4650b34644b95f2406920102e4d
6bc6f490707baeefbfcb154ff3822e8463c949ce
63718 F20101130_AABINY barron_m_Page_106.pro
0987e84ad3b5a1fec958304fc7f14c17
320417860be53347baab27717f428f6b1ce1eae0
1895 F20101130_AABIPB barron_m_Page_028.txt
4582da9e6f6fafa6c5dd02abc88802de
8c6f1650b0f25c96fa7b3e7e4ae8232af4bf9028
1700 F20101130_AABIOM barron_m_Page_012.txt
906e1e5adc79163dc51ec75c43b1c621
70c1f256dafd5eb69bdcdcaec8c5b1ea8a0beb59
51174 F20101130_AABINZ barron_m_Page_107.pro
85a0de9fcb939a2068e209f076fd1b65
bf1292a5d9b6a98992f5bb81dbb9ce49c234b904
1996 F20101130_AABIPC barron_m_Page_029.txt
1b3922e42066f9cab754096218c89801
5c6f62e949b47276ae280fd499f438d42df3544d
1944 F20101130_AABION barron_m_Page_013.txt
d4815afbe80b321f46ed18d3a8c4d56c
4763aa44ff8a44b4a71c0897b3e8c38f8217e242
1982 F20101130_AABIPD barron_m_Page_030.txt
f15770f6a37ec019d13e38ce2174fee3
fd5d2099e2f0329b55611c56c6f75f74ebe31ddc
1875 F20101130_AABIOO barron_m_Page_014.txt
ef7df8ac98b2639010aab4ebe52d2dad
1ad715dd61b4249a608484576af8d4f5407dd25e
2051 F20101130_AABIPE barron_m_Page_031.txt
20936921186f0fc001f54f1338ebeff8
7c57109d4bd0424e900c2417535013488a2b5f78
2025 F20101130_AABIOP barron_m_Page_015.txt
b3e231a70dc2fd5146cb388a3f61530f
517d02d3b3dcd5e5cde49eb12b90bee96062da77
1969 F20101130_AABIPF barron_m_Page_032.txt
25dab1da9d2ba0187c609083af68a38f
45a8f40713f4d85871be15ef1824d78e0db1468c
2083 F20101130_AABIOQ barron_m_Page_016.txt
6cb794c8cd7b25a886277b79793377d4
e7aa58545eeac8078c36495ba7ab70d26800bd07
247 F20101130_AABIPG barron_m_Page_033.txt
f3e20a4e3399bde11af6d930b3cb95b1
703192a3341e4b73f9d7c0a60199c0d129f178b5
2019 F20101130_AABIOR barron_m_Page_017.txt
744ae28d147d79ce96d08786669f1e92
8ce23e15bca539c36a526158c53adaa7615ba8e2
F20101130_AABIPH barron_m_Page_034.txt
c2e1acf371b2e7c99916087fef87fd5e
4cc755c32b3532c17cfd11e157c8d4b8cc2b306f
2047 F20101130_AABIOS barron_m_Page_018.txt
0eb3d9ddc0dd5f58e559e4b887a13f95
2431433c6b1584e439d398c822bbec2ca8585369
513 F20101130_AABIPI barron_m_Page_035.txt
99628c44d7ff2c4a7133570b91ce001c
485cdfd51afea541517e8af6f0510722a056d985
F20101130_AABIOT barron_m_Page_019.txt
5915a03ef7069055d6d2d28264f70f50
3c6577ef9a401f6660b92a79b790f6d6936b4eee
1846 F20101130_AABIOU barron_m_Page_020.txt
9f1fedeb7f49d593f8df2260c18f4ec2
071028d72355e6262486bfc7e2bfc0f8a8eea016
573 F20101130_AABIPJ barron_m_Page_036.txt
a40d04d3b8e60ea207448a226c571bf8
b534ecfd5bf491143699fcd1542e6004dc8af8cf
2063 F20101130_AABIOV barron_m_Page_021.txt
97ceb39ecf21ed90019e3fcf61b7e74f
5686a876c6d9f0dba43eb673b769613aebb2c93e
570 F20101130_AABIPK barron_m_Page_037.txt
0914733cba384cb8c7049cc5dcbf9cbc
7c4455dfe4eb351e50a6be75ea38bd474834c5db
2017 F20101130_AABIOW barron_m_Page_023.txt
54dc0142d156435900e105642fd0bd11
7da0285a4c92f4e15fdb268eb6377e78e49aeeae
954 F20101130_AABIQA barron_m_Page_055.txt
0b43c30119de3442969a4e4b7767f810
be606b920829664184ca6cbb2c0512e9c342a304
484 F20101130_AABIPL barron_m_Page_038.txt
2f6e3ce90e27fe21a47d8e6fa4ab564a
5d5a1f828a184b94a08d101222d25e8d1af308ed
571 F20101130_AABIOX barron_m_Page_024.txt
0dda240c2ec91e7cff3da09bdc716df4
5a93da735436e0fc7e9e752485787eacad215133
1367 F20101130_AABIQB barron_m_Page_056.txt
a11440047985f92822adebc8826550e7
f0a96e6485df53d94dddad08412852e1aa549e75
559 F20101130_AABIPM barron_m_Page_039.txt
27154fb9185fd960aafd5ee02a75ba6f
4634160b55808b22f017e513417dfc44577eb9f6
1803 F20101130_AABIOY barron_m_Page_025.txt
0e33041ddfc1363dff407364c20b487b
aa7a39479c73d39e028803ca942aa5f499dbb1f7
1593 F20101130_AABIQC barron_m_Page_057.txt
a1acab5b363ea5097ff5502e0e83ce29
cba3cf4d65b5be07e42f32d3743c4085a98f8089
511 F20101130_AABIPN barron_m_Page_040.txt
a6e21e8af1615d8da7c82b09dd19d7da
44c757b8fb178e1d8af42347dcd9a11105459c12
1860 F20101130_AABIOZ barron_m_Page_026.txt
3021ae43e67e3d20605a1bb5079abf66
6d25cc77a6625d39c3d5a446e8f97a749df02801
1107 F20101130_AABIQD barron_m_Page_058.txt
eeb0ba6f047eb3d98b98b49b4497730a
0f34e46efa859147784a62941e4c90b32c4a3fd7
652 F20101130_AABIPO barron_m_Page_041.txt
97f996d9b1a590cddf49ab97d51a3d8e
fe25d7d3ae36a562dfde6ee71b2d907ea7fe33cd
1155 F20101130_AABIQE barron_m_Page_059.txt
4c21662643f564993dbf988bcf4a4aeb
53ec591d2ea7cc39956052097ca0b048c46a943e
485 F20101130_AABIPP barron_m_Page_042.txt
14d9092b90371463fe4aae18c890eee5
a720cafa3967fb3088c3e17f6c001a0acc77cad1
530 F20101130_AABIPQ barron_m_Page_043.txt
553162ea2351e278f9c4195bd8345300
7e4937fc3489fdee03832219bf706b00e4063f5a
1920 F20101130_AABIQF barron_m_Page_061.txt
39f57db9500211b146324ec256660ecd
979d130f5d1aa6a64e7d5fb0f16be4d4a93da44d
500 F20101130_AABIPR barron_m_Page_044.txt
f5e0bf60500905ec20d65cdd220fadeb
34ccedca96d54ce64275fe8e3be489a82659b8ae
F20101130_AABIQG barron_m_Page_062.txt
0759e8f24fbb1b83c1a2f56f7d43ec39
43bfeee0d5eec8923c5041b1e3a9fc8e0dd6049f
536 F20101130_AABIPS barron_m_Page_045.txt
8b64974edfc219371a2f0d3454e763b5
341fd31293902c927f36f32de8b69ff0df00d563
1948 F20101130_AABIQH barron_m_Page_063.txt
262650b4f9647a3c6c0560ffb1dcbc6b
0e75c8ebd99a41abb5e3e1b86c1b96ddd87a8b37
F20101130_AABIPT barron_m_Page_046.txt
67c4a534b9a10cb9f5d78b47e86d8fc8
fe8ad088837b0d1a3d3f58af400bdcc43a257cfb
1742 F20101130_AABIQI barron_m_Page_064.txt
d57fae7125f64e559654796728578473
589a6ed558c7e7abfac74d25c418281968bbb589
462 F20101130_AABIPU barron_m_Page_047.txt
786c85961b1cd0204af1c01b706f6fb0
043d68f76dc378bc8f19c355f3d5eac7ff8f5f15
1804 F20101130_AABIQJ barron_m_Page_065.txt
bd6394cb7c793fbddd4a829688a59216
5e24c620ce855a086cbb8431420197242f259b27
591 F20101130_AABIPV barron_m_Page_048.txt
a0fe6e8a9b47b71205378bc7893cf523
b48d5d5baf73ee3327db8c4a80ce884a3066d12b
551 F20101130_AABIPW barron_m_Page_049.txt
ed931c47bb8c8dcaff3d95bb8e93aafc
fccbbbd603a7e9096e6baf653c6d733110b6b6ab
1997 F20101130_AABIQK barron_m_Page_066.txt
9c316e867403a596eedaa7857ebc92ed
19c1d8e14f2be0376f7e69422671a5eae084a315
669 F20101130_AABIPX barron_m_Page_050.txt
b26ffcca0ce8c7fd980da76152a25503
7152ce6bb41ab1bda3536e388416ddba5287ec3f
323 F20101130_AABIRA barron_m_Page_083.txt
3b433acdc67d4610214d127192987dbb
2a5304d50fe5c6b060d04b9c1b5ced044d49e7c7
F20101130_AABIQL barron_m_Page_067.txt
8101d404e8dee26718a4266bd0d42d70
677331c382c11894153c035ad6728ae82d1977af
587 F20101130_AABIPY barron_m_Page_052.txt
ca83b27c41428f9c6cd335cd3644bbdd
d058e4292882ca29137b3f2264253fa22a4e0d55
1158 F20101130_AABIRB barron_m_Page_084.txt
49849cfcff12f1032f651064e213fa72
3fe4dc6779b89211f02b818ff380a97e9420fd32
1949 F20101130_AABIQM barron_m_Page_068.txt
2c5efc739ed172186e44e232354cec3c
5739b60f376752e51c9534840a9726523ab99eef
F20101130_AABIPZ barron_m_Page_053.txt
b73c6ba980dc27ea36e26c7293c094f8
2cc1fc50ad60dbbe064f705242f647a36affd732
866 F20101130_AABIRC barron_m_Page_085.txt
10b39c9aa9ef16d7c06cadd43928b635
ae427bd4c9451efbd86df7931ad93a141087e56b
1960 F20101130_AABIQN barron_m_Page_069.txt
3d84dab7c100cc7e2c77059981d51601
afc70f45fb8c5dbde60f73d4d922f0c4b67f85fa
568 F20101130_AABIRD barron_m_Page_086.txt
9099d606cd62b24cd2242643010ae097
e803052ac822e5fa1f2ddef2290d59d63716d6a7
215 F20101130_AABIQO barron_m_Page_070.txt
4fe3beea1420b5007fb19bece50e37a8
027b44891e75fa060ecd129e0770a16efda8245c
729 F20101130_AABIRE barron_m_Page_087.txt
07551efd5cbe1a51872675924a2784cc
f02d04b15a0e0e5172c44d948d313ead7b52c0b3
1980 F20101130_AABIQP barron_m_Page_071.txt
89257abf486d0f036bae6052223f2de5
30285fbaf5f29db660954040511a14c047f3dbd9
1764 F20101130_AABIRF barron_m_Page_088.txt
87b603ec6425d4502055822a2db9387e
ba1d0cc0f6e22b88b43c6b66c6b25bf229dafab9
1897 F20101130_AABIQQ barron_m_Page_073.txt
08d3f5d33996d3c8e90de25c1dfb49b7
2bba9bb36c8fb57e5f0cc82a683d490087b54d6e
2069 F20101130_AABIRG barron_m_Page_089.txt
2e1a8085aec8cd03a9ba962e82a87c1a
a80f22cb9ae5dc6c09a425ba161dbd948746fce5
1898 F20101130_AABIQR barron_m_Page_074.txt
af0926d92fef094d36ffcfa4373e7428
946fd29b485ebc7a9527736160ec2c67e0e27da8
1965 F20101130_AABIRH barron_m_Page_090.txt
91cf4113e2a994da8c0e3a0e6fd54ef7
94828584e49e13ca4f3051a7890f94491bfbf544
1856 F20101130_AABIQS barron_m_Page_075.txt
fed2e2c2275cdb11a7e902d2707bea28
e2b20e791009cd959c38c7252c3f19a97bb26133
1992 F20101130_AABIRI barron_m_Page_091.txt
ba69b03ec744406334f6479d4bba18ab
33e7b721297cf0f487677639a6b45e1c2a0b60f0
1981 F20101130_AABIQT barron_m_Page_076.txt
55cae8d0ad128f0fcf25440155b062f3
8fd968c32a44dbd8970028f6c8cffafb721f6643
379 F20101130_AABIRJ barron_m_Page_092.txt
156119c5cd2fca4672e965d85d144fb7
a31427d9c031118cc397a106797a68fc6ba22300
2031 F20101130_AABIQU barron_m_Page_077.txt
70ee8afcac2391f98a04d7603e8c1899
3a0ac439f8fbee9c3433b534b24fb23f0a30f537
583 F20101130_AABIRK barron_m_Page_093.txt
3debf903d990d3d2528404673389b2b9
22ea2e176cd8d69767095509ab3884a2eb1ca997
1832 F20101130_AABIQV barron_m_Page_078.txt
df6cafeacc3d7a9188878991a5d4ca92
4839a5b8ce0061b8f4f896a371830c572c19e412
1926 F20101130_AABIQW barron_m_Page_079.txt
dbaf9dca70a845ec7b6992d5725354de
92537bd8ad5572b15f6656d31172ff14dc6ef3a6
1391 F20101130_AABISA barron_m_Page_002thm.jpg
3a6fa9085599687e4eea25ee918240a3
9545b1308cb8364fb51b2e33aac56182f5b5beb1
790 F20101130_AABIRL barron_m_Page_094.txt
b09ac1b5f61a5d89f6355c45688b27c6
e1cbcfa60d3a818ea558404edb4e22e2870152ee
2028 F20101130_AABIQX barron_m_Page_080.txt
164c871f58162b4e772ef4b7c1e42586
cae95b9e19405556ade1d207cb270d9dde798632
18728 F20101130_AABISB barron_m_Page_003.QC.jpg
3ce3d0e718d83773e0e63657d3f566b2
87acb0e5447226076794f8eaabdaf2219e77df17
853 F20101130_AABIRM barron_m_Page_095.txt
6da70e10849d9d11b051773e1da34ff8
76d32769c30bc796ccef20c0d680d6042b998813
1915 F20101130_AABIQY barron_m_Page_081.txt
200e6b5aa9e0a91b20cb98cbe3664bdb
f7a1376f66047ff6705891a80808790abf87c41d
5275 F20101130_AABISC barron_m_Page_003thm.jpg
0097f82b726cedbdc902238512e9fa9a
34c4356ede0841c8991326977d1c1cfb6f2be491
722 F20101130_AABIRN barron_m_Page_096.txt
176db23552c49b09014f6d322d94c8eb
1eea12353aa8dffadf6eaf50e0d509805204b096
1990 F20101130_AABIQZ barron_m_Page_082.txt
277d6794eaedb936e8585d5110b0e3d9
1bea426a0f0e53e0eb08e514b6b00c3086d88840
17714 F20101130_AABISD barron_m_Page_004.QC.jpg
eaaf136efb3b8ccda0fa8f676cb34a73
22270af60d84dc464e934dadd229850b49ad0b62
524 F20101130_AABIRO barron_m_Page_097.txt
a37bc6541bfc36b91be4d91f1443a478
9c018f121c133de902392d6ca17de4b7c47558d2
4790 F20101130_AABISE barron_m_Page_004thm.jpg
9758746353456cd0385f3e6fadc40884
987235df512e7f19dac2dfb4f7f88b5ba8f3e1e2
582 F20101130_AABIRP barron_m_Page_099.txt
8cf8dd008e3360900a99196cb8369272
d1ecb26e5ce6f1c1636df31f5606c0f18c72e4a1
7202 F20101130_AABISF barron_m_Page_005.QC.jpg
2db195cda9a8174ecfb5609805ee8ef9
96ae4b28b4a1b45e364c6c19bb7a72098c5a5356
F20101130_AABIRQ barron_m_Page_100.txt
e06f0bc958086600c48400eef38c8087
4053c4bbbdd456da44f1207c8391b2215e392a76
22828 F20101130_AABISG barron_m_Page_006.QC.jpg
9bf897ba45473d84dfad75cda229969d
b67706dde818f64f38a1273c3c926b231c6a74e2
736 F20101130_AABIRR barron_m_Page_101.txt
0f2966cf63dadd88e588e7f507386f11
957211413d91e328d0813d5e2ad352290b03dc02


Permanent Link: http://ufdc.ufl.edu/UFE0010801/00001

Material Information

Title: Residual Herbicide Impact on Native Plant Restoration as an Integrated Approach to Cogongrass Management
Physical Description: Mixed Material
Copyright Date: 2008

Record Information

Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
System ID: UFE0010801:00001

Permanent Link: http://ufdc.ufl.edu/UFE0010801/00001

Material Information

Title: Residual Herbicide Impact on Native Plant Restoration as an Integrated Approach to Cogongrass Management
Physical Description: Mixed Material
Copyright Date: 2008

Record Information

Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
System ID: UFE0010801:00001


This item has the following downloads:


Full Text












RESIDUAL HERBICIDE IMPACT ON NATIVE PLANT RESTORATION AS AN
INTEGRATED APPROACH TO COGONGRASS MANAGEMENT















By

MELISSA CAROLE BARRON


A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA


2005

































Copyright 2005

by

Melissa Carole Barron















ACKNOWLEDGMENTS

First and foremost, I would like to thank God for the strength and guidance He has

constantly provided for me. My parents, Bryant and Carol Barron, have been my biggest

fans throughout every moment of my life. I am grateful to my mother for her endless

love and encouragement. She has been and always will be the person I most aspire to

become. I thank my father for being such a supportive and loving dad and close friend.

He always lifts my spirits with a good laugh and kind words from his heart.

I thank my close friends Ron Emerson and Casey Jones for their love and

encouragement which have given me the confidence I need to get through the tough

times. Thanks go to my running friends, Tim Vinson, Debbie McCarthy, Elizabeth

Nelson, and Beth Martin, for motivating me in all aspects of life.

Endless appreciation is given to my major advisor, Dr. Greg MacDonald, for his

constant faith in my abilities to perform well in this graduate program. Having his vote

of confidence taught me to have a stronger believe in myself. Thanks go to Bob Querns

for similarly providing advice and good conversation throughout my time in this

program.

Finally, I thank Nick Pool for being my best friend and top supporter throughout

our time in graduate school. Our friendship extends from fieldwork to free time, and this

entire experience would not have been complete without him.
















TABLE OF CONTENTS

page

A C K N O W L E D G M E N T S ................................................................................................. iii

LIST OF TABLES ...................... ............... ...... ....... .............. vi

LIST OF FIGURES ...................................... ....... .......... ............. .. viii

ABSTRACT ........ ........................... .. ...... .......... .......... xii

CHAPTER

1 IN TR OD U CTION ............................................... .. ......................... ..

Cogongrass Characteristics.............. ...................... 1
Current M anagem ent Strategies ............................................................. ...............3
R ev eg station .................................................. ........................... 8

2 THE RESPONSE OF SELECTED REVEGETATION SPECIES TO
IMAZAPYR CONCENTRATIONS IN SOIL.........................................................12

Intro du action ...................................... ................................................ 12
M materials and M methods ....................................................................... .................. 15
R results and D discussion ....................................... ................ .. ..........16

3 IMAZAPYR RESIDUAL MEASUREMENTS USING CORN ROOT
B IO A S SA Y ........................................................................... 47

Introduction .............. ....... .............. ...... .... .......... ............ 47
M materials and M methods ....................................................................... ..................5 1
R results and D iscu ssion .............................. ......................... ... ........ .... ............53

4 NATURAL RECRUITMENT OF PLANT SPECIES IN AREAS PREVIOUSLY
INFESTED W ITH COGONGRASS ..................................... ......................... 62

In tro du ctio n ...................................... ................................................ 6 2
M materials and M ethods ......................................................... ........... ............ 65
Long Term Cogongrass Control .................................. ...................................... 66
R hizom e D distribution ................................................. ............................. 66
Native Species Recolonization ..... .............. .................66









R results and D discussion ............................. .... .............. .................. ............. 67
L ong Term C ogongrass C control .................................. ...................................... 67
R hizom e D distribution ................................................ .............................. 68
Native Species Recolonization ..... .............. ..................68

5 C O N C L U SIO N S ..................... .... .......................... ........ ........ ...... ........... 75

APPENDIX

STANDARD CURVES FOR CORN ROOT BIOASSAY ...........................................80

L IST O F R E F E R E N C E S ........................................................................ .....................9 1

B IO G R A PH IC A L SK E TCH ..................................................................... ..................95















LIST OF TABLES


Table page

2.1 Species used in revegetation study in Citra, Florida. ............................................. 42

2.3 The effect of imazapyr soil concentration on percent mortality of selected
revegetation species 10 weeks after planting. Experiment 2 initiated on July 21,
2004, in Citra, FL. P60 values reflect the predicted imazapyr concentration that
w would result in less than 60% m ortality. ....................................... ............... 44

2.4 The effect of imazapyr soil concentration on percent injury of selected
revegetation species 10 weeks after planting. Experiment 1 initiated on June 22,
2004, in Citra, FL. 130 values reflect the highest predicted imazapyr
concentration that would cause no greater than 30% injury. ..................................45

2.5 The effect of imazapyr soil concentration on percent injury of selected
revegetation species 10 weeks after planting. Experiment 2 initiated on July 21,
2004, in Citra, FL. 130 values reflect the highest predicted imazapyr
concentration that would cause no greater than 30% injury. ..................................46

3.1 The predicted concentration values of imazapyr using a corn root bioassay from
sand tailings soil in Polk C county ................................................................... .. ..... 58

3.2 The predicted concentration values of imazapyr using a corn root bioassay from
clay soil in Polk C county. ........................ ...... .............. ............ .... ...... ...... 58

3.3 The predicted concentration values of imazapyr using a corn root bioassay from
overburden soil in Polk C county ..................................................................... .. .. 59

3.4 Estimated revegetation timeframe as related to plant species and soil type
according to Experim ent 1 .............................................................................60

3.5 Estimated revegetation timeframe as related to plant species and soil type
according to E xperim ent 2. ........................................................... .....................61

4.1 Cogongrass control over a 4-year period. Visual ratings taken in January 2004
in P o lk C ou n ty .................................................. ................ 7 1

4.2 The effect of glyphosate and imazapyr on native species 39 months after
application in Polk County (area sprayed in Fall 2000)...............................71









4.3 Category 1 soil samples- no cogongrass within 0.6 meters of core samples.
Rhizome data taken 39 months after herbicide application in Polk County. ...........71

4.4 Category 2 soil samples- cogongrass within 0.6 meters of core samples.
Rhizome data taken 39 months after herbicide application in Polk County. ...........72

4.5 Category 3 soil samples- cogongrass present within core samples. Rhizome data
taken 39 months after herbicide application in Polk County. ................................72

4.6 Natural presence of species on sand soil type burned and treated with imazapyr
(Arsenal) in the fall of 2002 at Tenoroc WMA. Visual evaluations of percent
cover were taken in fall of 2004 (24 months after treatment). ..............................73

4.7 Natural presence of species on overburden soil type burned and treated with
imazapyr (Arsenal) in the fall of 2002 at Tenoroc WMA. Visual evaluations
of percent cover were taken in fall of 2004 (24 months after treatment) ...............74















LIST OF FIGURES


Figure pge

2.1 Andropogon virginicus (broomsedge) response to imazapyr concentration in soil
10 WAP (weeks after planting) immediately after imazapyr application for
experiment 1. Means of 4 replications present with standard error ......................21

2.2 Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 10
WAP (weeks after planting) immediately after imazapyr application.
Experiment initiated on June 22, 2004, in Citra, Florida. Means of 12
replications present with standard error. ...................................... ............... 22

2.3 Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil 10
WAP (weeks after planting) immediately after imazapyr application for
experiment 1. Means of 4 replications present with standard error ......................23

2.4 Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil 10
WAP (weeks after planting) immediately after imazapyr application for
experiment 1. Means of 4 replications present with standard error ......................24

2.5 Eucalyptus amplifolia response to imazapyr concentration in soil 10 WAP
(weeks after planting) immediately after imazapyr application for experiment 1.
M eans of 4 replications present with standard error. .......................... .... ...........25

2.6 Eucalyptus grandis response to imazapyr concentration in soil 10 WAP (weeks
after planting) immediately after imazapyr application for experiment 1. Means
of 4 replications present with standard error .................. ................ ............... 26

2.7 Panicum virgatum (switchgrass) response to imazapyr concentration in soil 10
WAP (weeks after planting) immediately after imazapyr application for
experiment 1. Means of 4 replications present with standard error ......................27

2.8 Andropogon virginicus (broomsedge) response to imazapyr concentration in soil
6 WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error ......................28

2.9 Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 6 WAP
(weeks after planting) immediately after imazapyr application for experiment 2.
Means of 4 replications present with standard error. .................... ..............29









2.10 Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil 6
WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error ......................30

2.11 Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil 6
WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error ......................31

2.12 Eucalyptus amplifolia response to imazapyr concentration in soil 6 WAP (weeks
after planting) immediately after imazapyr application for experiment 2. Means
of 4 replications present with standard error .................. ................ ............... 32

2.13 Eucalyptus grandis response to imazapyr concentration in soil 6 WAP (weeks
after planting) immediately after imazapyr application for experiment 2. Means
of 4 replications present with standard error .................. ................ ............... 33

2.14 Panicum virgatum (switchgrass) response to imazapyr concentration in soil 6
WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error ......................34

2.15 Andropogon virginicus (broomsedge) response to imazapyr concentration in soil
10 WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error ......................35

2.16 Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 10
WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error ......................36

2.17 Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil 10
WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error ......................37

2.18 Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil 10
WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error ......................38

2.19 Eucalyptus amplifolia response to imazapyr concentration in soil 10 WAP
(weeks after planting) immediately after imazapyr application for experiment 2.
M eans of 4 replications present with standard error. .......................... .... ...........39

2.20 Eucalyptus grandis response to imazapyr concentration in soil 10 WAP (weeks
after planting) immediately after imazapyr application for experiment 2. Means
of 4 replications present with standard error .................. ................ ............... 40

2.21 Panicum virgatum (switchgrass) response to imazapyr concentration in soil 10
WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error ......................41









A-1 The effect of imazapyr concentration on corn root length in a sand tailings soil
type in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in sand tailings soil 0 Months After Treatment (MAT).
V values show n in Table 3.1 ........... ................ ................................................... 80

A-2 The effect of imazapyr concentration on corn root length in a sand tailings soil
type in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in sand tailings soil 1 Month After Treatment (MAT).
V alues show n in Table 3.1 ............... ......................... ............... ..................... 81

A-3 The effect of imazapyr concentration on corn root length in a sand tailings soil
type in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in sand tailings soil 3 Months After Treatment (MAT).
Values shown in Table 3.1 ............... ......................... ............... ................82

A-4 The effect of imazapyr concentration on corn root length in a clay soil type in
Polk County, FL. Regression analysis used to determine unknown imazapyr
concentrations in clay soil 0 Months After Treatment (MAT). Values shown in
T ab le 3 .2 ............. ...... .. ............... ........................................83

A-5 The effect of imazapyr concentration on corn root length in a clay soil type in
Polk County, FL. Regression analysis used to determine unknown imazapyr
concentrations in clay soil 1 Month After Treatment (MAT). Values shown in
T able 3.2 ................ ......... .......................... ..........................84

A-6 The effect of imazapyr concentration on corn root length in a clay soil type in
Polk County, FL. Regression analysis used to determine unknown imazapyr
concentrations in clay soil 3 Months After Treatment (MAT). Values shown in
T ab le 3 .2 ............. ...... .. ............... ........................................85

A-7 The effect of imazapyr concentration on corn root length in an overburden soil
type in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in overburden soil 0 Months After Treatment (MAT).
V alues show n in Table 3.3. .............................................. ............................ 86

A-8 The effect of imazapyr concentration on corn root length in an overburden soil
type in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in overburden soil 1 Month After Treatment (MAT).
V alues show n in Table 3.3. ............................................. ............................. 87

A-9 The effect of imazapyr concentration on corn root length in an overburden soil
type in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in overburden soil 3 Months After Treatment (MAT).
V alues show n in T able 3.3. ........................................................... .....................88









A-10 Imazapyr concentration as a function of days after treatment (DAT) in a clay
soil type in Polk County, FL. Regression analysis used to determine imazapyr
concentrations over time after initial application of 0.84 kg ai/ha. Values shown
in T ab le 3 .4 ...................................................................... 8 9

A-11 Imazapyr concentration as a function of days after treatment (DAT) in an
overburden soil type in Polk County, FL. Regression analysis used to determine
imazapyr concentrations over time after initial application of 0.84 kg ai/ha.
V alues show n in T able 3.5. ........................................................... .....................90















Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

RESIDUAL HERBICIDE IMPACT ON NATIVE PLANT RESTORATION AS AN
INTEGRATED APPROACH TO COGONGRASS MANAGEMENT

By

Melissa Carole Barron

August 2005

Chair: Greg E. MacDonald
Major Department: Agronomy

Field studies were conducted to evaluate the impact of soil residues of imazapyr on

native species establishment. Both broomsedge and silkgrass showed at least 30% injury

at all rates of imazapyr, and only Eucalyptus grandis showed less than 30% injury at rates

above 0.033 kg ai/ha. Imazapyr caused significant injury to all species at rates higher than

0.56 kg ai/ha. Wax myrtle and longleaf pine showed greater than 60% mortality at the

lowest rate of imazapyr (0.018 kg ai/ha), while mimosa and both Eucalyptus species

show less than 60% mortality at the highest rate of 1.12 kg ai/ha.

Three areas were sprayed with 0.84, 1.68, and 3.36 kg ai/ha imazapyr in 2002 and

soil core sampling occurred immediately prior to application, immediately after

application, and at 1, 3, 6, and 12 months after treatment (MAT). Imazapyr concentration

was determined using a corn-root bioassay. At the lowest application rate of 0.84 kg

ai/ha, sand soil samples give a consistently similar rate at 0 MAT. There was no

detection of imazapyr at 1 MAT, and a trace amount was detected at 3 MAT (0.0005 kg









ai/ha). In the clay soil, samples taken 0 MAT were similar in value (0.078, 0.066, and

0.074 kg ai/ha for the plots sprayed with 0.84, 1.68, and 3.36 kg ai/ha, respectively). In

the overburden area, the plots treated with 0.84 kg ai/ha had measured residues that

decreased to 0.016 kg ai/ha 1 MAT and 0.0095 kg ai/ha 3 MAT. Overall, imazapyr

dissipation was faster in sand tailings, with mixed results occurring between clay and

overburden soil.

In the area treated in 2000, 25 random soil samples were taken from each plot and

categorized based on proximity to cogongrass. Approximately half of all samples were in

a cogongrass-free area for both glyphosate and imazapyr plots. Thirty-eight percent of

samples taken were within 2 feet of cogongrass and approximately half of these samples

contained rhizomes. Only 9 and 6% of samples from the glyphosate and imazapyr plots

were within cogongrass patch and all these samples contained rhizomes.

Bioassay data were combined with plant species injury and mortality data to create

a timetable to best estimate optimal planting dates per species. In both the clay and

overburden area, six species can be planted immediately after imazapyr application and

expect to show at least a 40% survival rate. E. grandis can be planted after one month in

clay and overburden to exhibit no more than 30% injury 10 weeks after planting (WAP).

E. amplifolia, mimosa, and bluejack oak also show slightly longer time periods in

overburden soils as compared to clay soils. Silkgrass and broomsedge need three months

before planting until soil residues are within range of 130 values. Wiregrass was the most

sensitive showing at least 30% injury at all rates of imazapyr regardless of plantback

interval. In a repeated study, similar predicted dates were generated according to 130

values for E. grandis and switchgrass.














CHAPTER 1
INTRODUCTION

Cogongrass [Imperata cylindrica (L.) Beauv.] is a rhizomatous perennial grass

species found throughout much of the tropical and sub-tropical regions of the world,

being widely distributed in Africa, Asia, Europe, North and South America, and Australia

(Holm et al. 1977). This species predominates in the eastern hemisphere, where it covers

over 200 million hectares in Asia alone (Garrity et al. 1996). Worldwide, cogongrass

infests over 500 million hectares and is considered the world's seventh worst weed

(Holm et al. 1977). In the United States, it is widely spread throughout Florida and much

of southern Alabama and Mississippi, infesting several hundred thousand acres (Johnson

et al. 1999). Cogongrass can usually be found in predominately non-agricultural settings

in the United States, and spreads over vast areas where vegetation is marginally

supported, suppressing and displacing many native plants (Bryson and Carter 1993).

Cogongrass Characteristics

First introduced into the U.S. as a packing material from Japan in 1912, cogongrass

initially invaded areas of Alabama (Dickens 1974). The weed was later introduced

purposefully in Mississippi as potential forage in 1921 (Patterson et al. 1979). Other

forage evaluations of cogongrass were later carried out in Texas, Alabama, Mississippi,

and Florida with spread being hindered from the Texas site due to winter kill (Dickens

and Moore 1974). Studies concluded that this potential forage was not suitable for

livestock because of its high silica content in the leaf tissue. This highly aggressive weed

is now a primary invader of disturbed lands, displacing desirable and native vegetation









(Terry et al. 1997). Unfortunately, the occurrence of cogongrass has increased drastically

during the past twenty years (Bryson and Carter 1993) and is currently reported in much

of the southeast United States.

Cogongrass tolerates a wide range of soil conditions but appears to grow best in

soils with acidic pH, low fertility, and low organic matter. Cogongrass infestations occur

in a wide range of habitats from shoreline course sands to the >80% clay soils of

reclaimed phosphate settling ponds (MacDonald 2004). Cogongrass is highly efficient in

nutrient uptake (Saxena and Ramakrishnan 1983) and reportedly has an association with

mycorrhiza, which may help explain its competitiveness in unfertile soils (Brook 1989).

Cogongrass is able to spread and persist through several survival strategies including an

extensive rhizome system, adaptation to poor soils, drought tolerance, prolific wind

disseminated seed production, fire adaptability, and high genetic plasticity (Holm et al.

1977; Dozier et al. 1998). With the exception of a flowering stalk, cogongrass is virtually

stemless. The leaves are slender, flat, and linear-lanceolate, and possess serrated margins

and a prominent off-center white mid-rib (Terry et al. 1997). Silicates accumulate in the

serrated margins of the leaves, which deter herbivory (Dozier et al. 1998).

Cogongrass rhizomes can comprise over 60% of the total plant biomass (Sajise

1976). This low shoot to root/rhizome ratio contributes to its rapid regrowth after cutting

or burning. Cogongrass rhizomes are white and tough with shortened internodes.

Specialized anatomical features help to conserve water within the central cylinder and

help to resist breakage and disruption when trampling or disturbance occurs (Holm et al.

1977). Rhizomes are predominately found within the top 15 cm of fine textured soils or

the top 40 cm of course textured soils. However, rhizomes have been discovered









growing at depths of 120 cm (Holm et al. 1977; Gaffney 1996). According to Tominaga

(2003), cogongrass rhizomes can be grouped in the following three categories: tillering,

secondary colonizing, and pioneer rhizomes. Unlike cogongrass seedlings, which are

defined as R-strategist (ruderal) and invade open patches in disturbed habitats, rhizomes

from current cogongrass stands are defined as C-strategist (competitor) that can persist in

established populations (Tominaga 2003). These rhizomes provide a tremendous amount

of biomass for regeneration after foliar loss, with one study showing rhizome length of

over 89 meters within one square meter of soil surface area (Lee 1977).

Cogongrass is also a prolific seed producer, with shortly branched, compacted and

dense seed heads producing over 3000 seeds per plant. Each brownish colored seed

(grain) possesses a plume of long hairs that affect wind dispersal. These plumed seeds

travel over long distances averaging 15 meters (Holm et al. 1977), but Hubbard (1944)

stated that cogongrass seeds could travel up to 24 kilometers over open country.

Flowering is highly variable depending on region and environment. Cogongrass

flowering occurs year-round in the Philippines (Holm et al. 1977), whereas flowering in

the United States occurs in the late winter/early spring (Shilling et al. 1997).

Disturbances including burning, mowing, grazing, frost, or the addition of nitrogen can

also stimulate flowering (Holm et al. 1977; Soerjani 1970; Sajise 1972).

Current Management Strategies

Current control methods for cogongrass rely heavily on chemical treatments, which

provide limited long-term control. The main reason for this limited control is the

presence of cogongrass rhizomes, which can comprise over 2/3 the total plant biomass.

These rhizomes contain multiple nodes from which regrowth may occur, but generally

only a fraction sprout at any given time (English 1998). Mowing is also often included as









a control method with chemical application. While mowing alone does not effectively

control cogongrass, it has been shown to reduce rhizome and foliar biomass (Willard and

Shilling 1990). However, the integration of mowing with chemical applications resulted

in poor control compared to conventional application techniques (Marchbanks et al.

2002). Cultivation has proven effective, with little or no regrowth occurring under

continuously cultivated conditions (Hartley 1949). However, the high costs and limited

utility in many areas precludes use of this type of method. Johnson et al. (1999) showed

that a single discing in combination with herbicides did not significantly enhance

cogongrass control compared to herbicide alone. A second discing provided better

control than just single discing but also did not enhance control over herbicide treatments.

Therefore, sporadic mechanical control treatments are less effective than other

approaches and often exacerbate the situation.

Over the last three decades, several herbicides have been evaluated for cogongrass

control with minimal success (Dickens and Buchanan 1975). Presently, the most

effective herbicides are glyphosate [N-(phosphonomethyl)glycine] and imazapyr {(+)-2-

[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imadazol-2-yl]-3-pyridinecarboxylic

acid (Dozier et al. 1998). Generally, imazapyr provides control for a longer period of

time due to soil activity, but off-target effects limits use in certain areas (MacDonald et

al. 2002). These chemicals are broad-spectrum, systemic herbicides that, in general, can

effectively control cogongrass for one year after application (Miller, 2000). Imazapyr is

used to control annual and perennial weeds, deciduous trees, and vines in rights-of-way

and other noncropland areas, as well as in forestry as a conifer releasing agent (Anon.

2002). The mode of action of imazapyr, a member of the imidazolinone family of









herbicides, involves the inhibition of acetohydroxyacid synthase (AHAS), which is

needed for branched chain amino acid synthesis (Shaner 1991). Field half-life values

range from 25-142 days depending on soil type and environmental conditions, with soil

adsorption increasing as organic matter and clay content increase (Anon. 2002).

Imazapyr is relatively harmless to animals, and if used correctly, has minimal off-target

impacts (Mangels 1991). Research to date has indicated imazapyr at 1.12 kg ai/ha applied

late summer/early fall provides cogongrass control for as long as 18 months (Dozier et al.

1998). This application timing has been attributed to the basipetal flow of photosynthates

and herbicides that occur at this time of year, which results in improved rhizome lethality

(Gaffney 1996). After this time, cogongrass will re-form a monotypic stand within 1-2

years if additional treatments are not imposed (Dozier et al. 1998). Burning prior to

herbicide application has shown the ability to remove old growth and dead biomass and

provides several benefits (Johnson et al. 1999). Starch storage reserves in rhizomes are

forced to re-allocate to produce new shoot growth, thereby weakening the rhizomes.

Also, removal of the substantial biomass improves the ability to effectively apply

herbicides. Herbicide application to the regrowth of new plant tissues also maximizes

absorption and results in greater efficacy (Johnson et al. 1999).

Imazapyr provides good control of cogongrass but has limited utility due to the

long residual effects of this compound, which could hinder revegetation strategies and

native recruitment. In previous research, several native species were evaluated under

greenhouse conditions for response to imazapyr used in non-cropland situations.

Imazapyr caused severe injury to most species evaluated, but injury was restricted to a

foliar application only (Miller et al. 2002). A more accurate assessment of successful









native species growth and establishment is when the concentration of residual herbicide

in the soil is at a tolerable level. Initial research indicates the residual activity of

imazapyr may be less than theorized, allowing for more flexibility in a revegetation

scheme. A better understanding of native species response to imazapyr soil concentration

could provide greater flexibility when developing revegetation schemes. Varying initial

rate and time of transplanting after application could provide land managers with a

greater number of native species to select.

Other major factors in the determination of timing and revegetation include the

total amount of chemical used and the soil type to which the herbicide is applied. Soil

type has an important influence on the residual amount of herbicide due to the soil

structure and content of clay and organic matter. In sandy soils, there are fewer charged

sites that the herbicide can adsorb to, and leaching often occurs. Therefore, sandy soils

contain less residual matter after a given period of time than a clay soil, which has a

much greater affinity for adsorption (McBride, 1994). Also, herbicides tend to persist

longer in loamy and silty soils due to reduced leaching compared to sandy soils. Because

of the diversity of soils in Florida, as well as much of the U.S., an understanding of

herbicide persistence as a function of soil type is important in predicting the best time to

revegetate.

In central Florida, reclaimed mining sites have a diverse collection of soil types

with overburden, sand tailings and phosphatic clay pits being three of the most prominent

(Richardson et al. 2003). Overburden, a mixture of sand and clay, is removed from the

land surface above the ore body and piled on the side. Overburden shows the highest

variability in soil texture, soil color and soil chemical parameters (Segal et al. 2001).









This soil type is on average composed of 80% sand, 8% silt, and 12% clay with a pH of

5.8.1 Overburden has slightly greater clay and silt content, higher water-holding capacity,

and greater P and K content than native Floridian soils, which may give aggressive weeds

a competitive advantage over slower-growing natives (Richardson et al. 2003). The

phosphate ore currently being mined is an unconsolidated mixture of sand, clay, and

phosphate mineral. The sand tailings are separated from this ore and hydraulically

pumped to fill mine cuts between overburden piles. Although sand tailings are usually

nutrient-poor and drought compared with these three other soil types (Segal et al. 2001),

they have higher P and K contents and slightly coarser grain sizes than native soils

(Kluson et al. 2000). Phosphatic clay is washed from phosphate ore and pumped, at

about 3-5% solids, to settling areas. This clay commonly has pH values near 7.5, while

some older sites with good forest cover and higher organic matter have pH values near

6.8. This soil type covers about 40% of the mined area and is considered highly fertile

(Stricker 2000).

These three soil types involved in phosphate mining processes are highly diverse in

nature, yet they are all susceptible to cogongrass and other non-native weed invasions.

This is due to the disturbance of the areas during the mining process and the associated

harsh conditions to which plants are subjected.

For long-term control of cogongrass, further methods need to be integrated into the

traditional control techniques mentioned above. Even in areas where management has

been successful, cogongrass re-infestation will often occur. Because of this, studying the


1 Richardson, S.G. 2004. Personal Communication.









reinfestation aspects of cogongrass, especially from rhizomes, is also an important aspect

of overall integrated control.

Revegetation

In Florida, reclaimed phosphate mining areas are important areas for cogongrass

control and native plant restoration. Because mining disturbance creates a hospitable

environment for weed invasion, one of the most difficult barriers to successful restoration

is the control of cogongrass and other invasive weeds. Effectively returning mined lands

and lands infested with cogongrass to self-sustaining native upland communities with

functional ecological value would be beneficial to the mining industry, local

communities, and the state of Florida (Miller et al. 2002). Mined land restoration is

crucial in Florida because upland ecosystems in Florida have been dramatically reduced

in area (Richardson et al. 2003) due to a variety of causes, including mining,

development, and agriculture. Determining which species will be most successful in a

restoration scheme involves several factors, such as imazapyr tolerance, competitiveness

with cogongrass and other invasive species, and overall desirability.

The cornerstone of integrated management and restoration is the establishment of a

self-sustaining native plant community. Previous studies show that wiregrass (Aristida

beyrichiana Trin. and Rupr.) is a pivotal native grass in areas of phosphate mining and is

highly desired for use in reclamation (Norcini et al. 2003). Wiregrass is often the

dominant grass species in Florida uplands, and foresters have long preferred this species

as well as broomsedge (Andropogon virginicus L.) for pine forest understory because of

their ability to carry a fire (Pfaff et al. 2002). Silkgrass [Pityopsis graminifolia (Michx.)

Nutt.] also proved highly adaptable to reclaimed mining land soils and was selected as a

candidate for future large-scale assembly and seed source development (Pfaff et al.









2002). Gopher apple (Licania michauxii Prance) is a drought-tolerant woody plant native

to Florida uplands, is locally abundant, and can function as a ground cover. It is

consistently demanded for use in a variety of restoration and mitigation projects, and it is

a prime candidate for use in mine reclamation (Norcini et al. 2003). Another species of

interest is lovegrass [Eragrostis spectabilis (Pursh) Steud.]. This pioneer species is

important because it has the potential to be a good competitor against aggressive species

while allowing other slow-growing species to become established (Segal et al, 2001).

Wax myrtle [Myrica cerifera (L.) Small], switchgrass (Panicum virgatum L.), and

creeping mimosa (Mimosa strigillosa Torr. and Gray) are three additional perennial

species that have been studied in plantback studies involving imazapyr (Miller et al,

2002).

Tree species are also important in successful native plant restoration. Weed

management in pine (Pinus spp.) has been extensively studied, and imazapyr is widely

used in pine culture throughout the south (Lauer et al. 2002). Longleaf pine (Pinus

palustris P. Mill.) is native to Florida and is widely desired in revegetation scenarios. In

addition to pines, Florida was historically heavily forested with stands of bluejack oak

(Quercus incana Bartr.) and sand live oak (Quercus geminata Small). Recent studies

have tested imazapyr as a site preparation herbicide for oak species with promising

results (Schuler et al. 2004). Other trees for potential use in a revegetation scheme are

eucalyptus (both Eucalyptus grandis W. Hill ex Maid. and Eucalyptus amplifolia

Naudin). Although these eucalyptus species are considered exotic and non-native, they

are shown to be non-invasive. This is because eucalyptus has been grown in south and

central Florida since the 1970's with no evidence of escaping into the environment









(Rockwood 1996). These trees are potentially good at suppressing cogongrass after

initial control because of good growth during the first year while typically dominating

other vegetation for the rest of the rotation (Stricker 2000). Eucalyptus also grows faster

than native tree species in peninsular Florida (Rockwood et al. 1996), making them good

candidates for bioenergy crop production. The humid Lower South has the most suitable

climate (warm temperature, high rainfall, and longest warm growing season) for biomass

crops in the continental US, and Eucalyptus species, especially Eucalyptus grandis, is

now showing the greatest potential for reclaimed mining lands (Prine and French 1999).

Under intensive cultivation and close spacing, E. amplifolia can yield as much as 25 dry

mg/ha/yr on good sites in northeastern Florida, and E. grandis can yield up to 35 dry

mg/ha/yr in central and southern Florida (Prine and French 1999; Segrest et al. 1998).

This wide selection of both native and non-native plant species possesses qualities

that are desirable for many revegetation studies for reclamation. Characteristics such as

tolerability to variable amounts of imazapyr in the soil and effective competitiveness with

cogongrass regrowth are important in choosing which plant species to use in successful

revegetation work. In combination with more traditional control methods, a

comprehensive revegetation plan might be the most important link in overall cogongrass

control and spread prevention.

If complete cogongrass control is the ultimate goal, the utilization of current

management techniques has been shown to be only marginally successful. Eradication

with herbicides such as imazapyr is theoretically possible but is undesirable for several

reasons. This type of approach invites erosion, is unsightly, and will prevent the

introduction of desirable native species. Ideally, cogongrass should be gradually






11


eliminated while desirable species are introduced. Taking into consideration factors such

as residual herbicide amount, plant tolerance levels, and soil types can be very beneficial

to an overall cogongrass control strategy. Also, visual monitoring of both disturbed and

undisturbed areas previously treated for cogongrass will provide information on plant

succession, rhizome dormancy and spread, and long-term growth habits of cogongrass in

competition with other, more desirable plant species.














CHAPTER 2
THE RESPONSE OF SELECTED REVEGETATION SPECIES TO IMAZAPYR
CONCENTRATIONS IN SOIL

Introduction

Cogongrass [Imperata cylindrica (L.) Beauv.] is an aggressive perennial grass

species which infests over 500 million hectares worldwide and is considered the world's

seventh worst weed (Holm et al. 1977). In the United States, it is widely spread

throughout Florida and much of southern Alabama and Mississippi, infesting several

hundred thousand acres (Johnson et al. 1999). Cogongrass can usually be found in

predominately non-agricultural settings in the United States. Cogongrass tends to spread

over vast areas where vegetation is marginally supported, suppressing and displacing

many native plants (Bryson and Carter 1993). Cogongrass tolerates a wide range of soil

conditions but appears to grow best in soils with acidic pH, low fertility, and low organic

matter. This invasive plant is able to spread and persist through several survival

strategies including an extensive rhizome system, adaptation to poor soils, drought

tolerance, prolific wind disseminated seed production, fire adaptability, and high genetic

plasticity (Holm et al. 1977, Dozier et al. 1998).

Current control methods for cogongrass rely heavily on chemical treatment, which

provides limited long-term control. To date, the most effective herbicides for cogongrass

management are glyphosate and imazapyr (Dozier et al. 1998; Barnett et al. 2000;

MacDonald et al. 2002). Generally, imazapyr provides control for a longer period of

time due to soil activity, but off-target effects limits use in certain areas (MacDonald et









al. 2002). Research to date has indicated imazapyr at 1.12 kg-ai/ha applied late

summer/early fall provides control for as long as 18 months (Dozier et al. 1998).

Burning prior to herbicide application provides several benefits including rhizome

weakening due to new shoot growth and removal of old biomass for more effective

herbicide application (Johnson et al. 1999).

Imazapyr provides good control of cogongrass but has limited utility in reclamation

projects due to the long residual effects of this compound. Although there is ample

information on the effect of several herbicides on weedy species, little information

regarding the herbicide tolerance (i.e., selectivity potential) of native species is available.

In previous research by Miller et al. (2002), several native species were evaluated under

greenhouse conditions for response to imazapyr used in non-cropland situations.

Imazapyr caused severe injury to most species, but this injury was reflective to a foliar

application only. In most practical field situations, herbicides are usually sprayed to

control cogongrass with little or no subsequent control measures. These areas often

become reinfested because of a lack of suppressive cover and/or incomplete initial

control. An important step in the further suppression of cogongrass is to establish a

native plant cover as soon as the residual herbicide levels in the soil become tolerable to

the revegetation species. It is important to quantify soil residual levels to best predict

effective revegetation timing for the most effective suppression of cogongrass.

Therefore, an understanding of plant species response to imazapyr residues in soil will

ultimately be beneficial for restoration purposes in southeastern ecosystems (MacDonald

et al., 2002).









Many plants tolerate herbicides, including imazapyr, differentially, so an

understanding of the effects of imazapyr on the selected revegetated species is crucial.

Determining which species will be most successful in plantback situations involves

several factors, such as imazapyr tolerance, competitiveness with cogongrass and other

invasive species, and overall desirability. Because the cornerstone of integrated

management and restoration is the establishment of a self-sustaining native plant

community, primary emphasis for this study was placed on native Floridian plant species.

Species such as wiregrass (Aristida beyrichiana), broomsedge (Andropogon virginicus),

and silkgrass (Pityopsis graminifolia) are desired native grasses for use in reclamation

(Norcini et al. 2003). Woody plants such as gopher apple (Licania michauxii), wax

myrtle (Myrica cerifera), and creeping mimosa (Mimosa strigillosa) have also been

studied in plantback research involving imazapyr (Miller et al, 2002). Other species of

interest are lovegrass (Eragrostis spectabilis) and swichgrass (Panicum virgatum), which

can potentially be good competitors against aggressive species while allowing other

slow-growing species to become established (Segal et al, 2001).

Tree species are also important in successful native plant restoration. Longleaf

pine (Pinuspalustris) is native to Florida and is widely desired in revegetation schemes.

In addition, Florida was historically heavily forested with stands of bluejack oak

(Quercus incana) and sand live oak (Quercus geminata). Recent studies have tested

imazapyr as a site preparation herbicide for oak species with promising results (Schuler et

al. 2004). Other trees for potential use in a revegetation scheme are eucalyptus (both

Eucalyptus grandis and Eucalyptus amplifolia). Although these eucalyptus species are

considered exotic and non-native, they are non-invasive. These trees are potentially good









at suppressing cogongrass after initial control because they show good growth during the

first year while typically dominating other vegetation for the rest of the rotation (Stricter

2000). Eucalyptus also grow faster than native tree species in peninsular Florida

(Rockwood et al. 1996), making them good candidates for bioenergy crop production.

This wide selection of both native and non-native plant species possesses qualities

that are desirable for many revegetation scenarios. Characteristics such as tolerability to

variable amounts of imazapyr in the soil and effective competitiveness with cogongrass

regrowth are important in choosing which plant species to use in successful revegetation

work.

Materials and Methods

Field experiments were conducted in the summer of 2004 at the Plant Science

Research and Education Unit (PSREU) in Citra, Florida. The soil type at Citra is a Sparr

sand (loamy, siliceous, hyperthermice Grossa-renic paleudult) with 1% organic matter

and a pH of 6.4. The field area was conventionally prepared using standard tillage

practices. Imazapyr (Arsenal 4 SC) was applied at 0.0, 0.018, 0.036, 0.071, 0.14, 0.28,

0.56, and 1.12 kg-ai/ha using a backpack CO2 sprayer calibrated to deliver 187 L/ha.

Applications occurred on June 22 and July 21, 2004, for the first and second experiments,

respectively. Immediately after application, the herbicide was lightly incorporated into

the soil to a depth of 5 to 7.6 centimeters. Plots were 6 x 7.6 m2 plots and arranged in a

completely randomized block design with four replications. Within 24 hours of herbicide

application, 3 seedling plants of each species were hand planted into the soil in a 76 cm x

76 cm spacing per plant. A native plant nursery supplied all native plant seedlings used









in the studies,1 and the two Eucalyptus species were obtained from Dr. Don Rockwood of

the University ofFlorida.2 Common name, scientific name, and plant size at time of

transplanting for all species are listed in Table 2.1. All species were evaluated for

percent mortality at 10 weeks after planting. In addition, several species were evaluated

for percent injury at 6 and 10 weeks after planting where 0 = no injury and 100 = plant

death. Data were subjected to analysis of variance to test for main effects and

interactions. Regression analysis was used to predict species response to imazapyr.

Results and Discussion

There was a significant interaction (p< 0.05) between experiments; therefore data

for the two studies are reported separately. Of the 13 species used in the revegetation

study, only 7 were observed for percent injury in each experiment. These seven species

showed the greatest range of injury over the varying levels of imazapyr in the soil.

Mortality ratings were recorded for all 13 species.

Mortality data for experiment 1 are shown in Table 2.2. Regression analysis was

used to predict the mortality response to imazapyr for each species. P60 values were

calculated to define the highest amount of imazapyr in the soil at which at least 40% of

plants remaining alive. Due to the slow activity of imazapyr, only the 10 WAP data is

shown to allow for greatest plant response and possible recovery. In this experiment,

only E. amplifolia showed less than 60% mortality at all rates of imazapyr, followed by

M. strigillosa, which could tolerate imazapyr up to 0.82 kg ai/ha. P. palustris and E.

grandis had P60 values of 0.443 and 0.381 kg ai/ha, which were still significantly greater


1 The Natives, Inc., Davenport, FL, USA.
2 Professor of Tree Improvement, University of Florida School of Forest Resources and Conservation,
Gainesville, FL, USA.









than the other species listed in Table 2.2. P. graminifolia and A. beyrichiana had P60

values of 0.17 and 0.11 kg ai/ha imazapyr, while Q. geminata, A. virginicus, L.

mixhauxii, and E. spectabilis were the most sensitive to imazapyr with P60 values from

0.066 to 0.041 kg ai/ha imazapyr. Only M. cerifera showed greater than 60% mortality

ratings at all levels of imazapyr in the soil, but this could be reflective of low transplant

survival, not necessarily sensitivity to imazapyr.

Mortality data for experiment 2 are shown in Table 2.3. In this experiment, most

species showed greater tolerance to imazapyr than in experiment 1, which is reflected in

greater P60 values. E. amplifolia, E. grandis, M. strigillosa, and L. michauxii all showed

less than 60% mortality at all rates of imazapyr. A. beyrichiana showed a tolerance up to

0.974 kg ai/ha, followed by P. graminifolia and P. virgatum, with values of 0.773 and

0.739 kg ai/ha, respectively. A. virginicus was moderately sensitive with a P60 value of

0.544 kg ai/ha, followed by Q. geminata and E. spectabilis (0.437 and 0.325 kg ai/ha

imazapyr). Data for Q. incana had such high variability that a response could not be

calculated. P. palustris and M. cerifera showed greater than 60 % mortality ratings at all

levels of imazapyr in the soil.

Only 10 WAP injury data were recorded in experiment 1. All seven species

evaluated exhibited an exponential increase in injury score in response to imazapyr

injury. In Table 2.4, 130 values were calculated for species 10 WAP. These are values of

imazapyr in soil (kg ai/ha) that cause no more than 30% injury to the plant species.

Andropogon virginicus showed immediate dose response at very low concentrations

increasing up to 0.15 kg ai/ha imazapyr (Figure 2.1), with injury of 83%. Injury levels

did not increase dramatically as the rates increased from 0.15 to the maximum rate of









1.12 kg ai/ha. A. virginicus exhibited 20% injury in the plots where there was no

imazapyr, which might be reflective of transplant stress. Mimosa strigillosa and Aristida

beyrichiana exhibited a more gradual response to imazapyr with increasing herbicide

concentration (Figures 2.2 and 2.3), although M. strigillosa showed less injury at 0.4 kg

ai/ha than A. beyrichiana (63% and 90%, respectively). A. beyrichiana also showed

injury (38%) in areas where there was no imazapyr, again reflective of potential

transplant stress of the seedlings. Pityopsis graminifolia also had a relatively high injury

rate at 0.2 and 0.4 kg ai/ha (78 and 90% injury) as seen in Figure 2.4. Eucalyptus

amplifolia and E. grandis, the two energy crop species, had comparatively low injury

responses at 0.2 kg ai/ha (66 and 60%, respectively) when compared to the other species

in the study (Figures 2.5 and 2.6). Also, Panicum virgatum showed 69% injury at 0.2 kg

ai/ha (Figure 2.7). Of the 7 species, M strigillosa, E. amplifolia, and E. grandis showed

the lowest injury ratings at 0.2 kg ai/ha (no greater than 66%).

For experiment 2, both 6 and 10 WAP injury data were recorded. Once again, the

relationship between injury and imazapyr rate was exponential, but overall percent injury

per concentration was lower in this experiment. In Table 2.5, 130 values were calculated

for species 10 WAP. These are the highest values of imazapyr in soil (kg ai/ha) that

cause no more than 30% injury to the plant species. A. beyrichiana and P. graminifolia

showed the lowest injury at 0.2 kg ai/ha of all the 7 species monitored (41 and 40%,

respectively) at 6 WAP, shown in Figures 2.10 and 2.11. Even at the highest rate of 0.4

kg ai/ha imazapyr, these two species show a minimal increase in injury (60% injury for

A. beyrichiana and 55% for P. graminifolia) at 6 WAP. At 10 WAP, these two species

have only a slight increase in injury at 0.4 kg ai/ha (64% for both species), as shown in









Figures 2.17 and 2.18. M. strigillosa follows a similar trend, with 44% injury at 0.2 kg

ai/ha and 59% injury at 0.4 kg ai/ha 6 WAP (Figure 2.9). At 6 WAP, M. strigillosa

showed no greater than 78% damage at the maximum rates of imazapyr. M. strigillosa

showed no significant change in reported injury between 6 and 10 WAP for rates of 0.4

kg ai/ha imazapyr (59 and 61%, respectively). A. virginicus showed 33% injury at 6

WAP in plots with no imazapyr, as well as 39% injury in the same plots 10 WAP. This

high rate of injury is thought to be related to either transplanting or water stress (due to

three days without watering immediately after transplanting in experiment 2). E.

amplifolia and E. grandis showed higher rates of injury compared to experiment 1 at 0.4

kg ai/ha for both 6 and 10 WAP, as shown in Figures 2.12, 2.13, 2.19, and 2.20. E.

amplifolia exhibited 76 and 78% injury at 0.4 kg ai/ha at 6 and 10 WAP, while E.

grandis exhibited 75 and 80% injury at 6 and 10 WAP. P. virgatum had a marked

increase in injury from 6 to 10 WAP for both 0.2 and 0.4 kg ai/ha imazapyr, as shown in

Figures 2.14 and 2.21 (44 and 65% 6 WAP and 57 and 74% 10 WAP).

Overall, both Eucalyptus species, M. strigillosa, A. beyrichiana, and P.

graminifolia show low mortality response to imazapyr in soil. However, E. amplifolia

and E. grandis both show higher injury response than many other species to imazapyr in

this study. These data show that these species might be able to "outgrow" the imazapyr

injury after some period of time. Even though a plant might show initial injury

symptoms, the overall ability of that plant to recover is a very important quality to look

for in a potential revegetation species.

In addition to these data regarding the most tolerant species to be used as

revegetation species, it is important to consider the costs involved with transplanting, as






20


well as the overall desirability of the species by landowners. These data are beneficial

from a research standpoint, but economic aspects should be taken into consideration as

well.





























40


20



0
0.0


0.2 0.4 0.6 0.8 1.0


imazapyr concentration (kg ai/ha)








Figure 2.1. Andropogon virginicus (broomsedge) response to imazapyr concentration in
soil 10 WAP (weeks after planting) immediately after imazapyr application
for experiment 1. Means of 4 replications present with standard error.

























20


0.0 0.2 0.4 0.6 0.8 1.0 1.2
imazapyr concentration (kg ai/ha)




Figure 2.2. Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 10
WAP (weeks after planting) immediately after imazapyr application.
Experiment initiated on June 22, 2004, in Citra, Florida. Means of 12
replications present with standard error.





























40


20


0 I I I I I
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)





Figure 2.3. Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil
10 WAP (weeks after planting) immediately after imazapyr application for
experiment 1. Means of 4 replications present with standard error.





























40


20


0 I I I I I
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)






Figure 2.4. Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil
10 WAP (weeks after planting) immediately after imazapyr application for
experiment 1. Means of 4 replications present with standard error.




























40


20




0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)






Figure 2.5. Eucalyptus amplifolia response to imazapyr concentration in soil 10 WAP
(weeks after planting) immediately after imazapyr application for experiment
1. Means of 4 replications present with standard error.





























40 -



20 -



0
0 I I----------------------------
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)






Figure 2.6. Eucalyptus grandis response to imazapyr concentration in soil 10 WAP
(weeks after planting) immediately after imazapyr application for experiment
1. Means of 4 replications present with standard error.





























40 -


20 -
20




0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)






Figure 2.7. Panicum virgatum (switchgrass) response to imazapyr concentration in soil
10 WAP (weeks after planting) immediately after imazapyr application for
experiment 1. Means of 4 replications present with standard error.




























40 y=32.7+25.0*(1-exp(-14.5*x))+149557.6*(1-exp(-0.0002*x))
R2=0.61

20


0 I I I I I
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)





Figure 2.8. Andropogon virginicus (broomsedge) response to imazapyr concentration in
soil 6 WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error.































20 '




0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)






Figure 2.9. Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 6
WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error.































20 .



0I I I
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)





Figure 2.10. Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil
6 WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error.































20



0
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)






Figure 2.11. Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil
6 WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error.





























20-


0 I I I I I
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)





Figure 2.12. Eucalyptus amplifolia response to imazapyr concentration in soil 6 WAP
(weeks after planting) immediately after imazapyr application for experiment
2. Means of 4 replications present with standard error.
































20 -I


0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)






Figure 2.13. Eucalyptus grandis response to imazapyr concentration in soil 6 WAP
(weeks after planting) immediately after imazapyr application for experiment
2. Means of 4 replications present with standard error.
























207


0.0 0.2 0.4 0.6 0.8 1.0 1.2
imazapyr concentration (kg ai/ha)




Figure 2.14. Panicum virgatum (switchgrass) response to imazapyr concentration in soil
6 WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error.














120



100 -


80 -


60


40 y=39.2+45.3*(1-exp(-5.9*x))
R2=0.41




20 -

0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)



Figure 2.15. Andropogon virginicus (broomsedge) response to imazapyr concentration in
soil 10 WAP (weeks after planting) immediately after imazapyr application
for experiment 2. Means of 4 replications present with standard error.














100



80 -



60 -








20
S40 R




20





0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)

Figure 2.16. Mimosa strigillosa (mimosa) response to imazapyr concentration in soil 10
WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error.














100



80 -



6 60
40



y=5.5+22.8*(1 -exp(-60.4*x))+63.5*(1-exp(-2.6*x))
R2=0.97






0 I
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)

Figure 2.17. Aristida beyrichiana (wiregrass) response to imazapyr concentration in soil
10 WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error.














100



80



60


1 y=27.5+59.9*xA0.5
40 < R2=0.75



20 0
20





0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)

Figure 2.18. Pityopsis graminifolia (silkgrass) response to imazapyr concentration in soil
10 WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error.














100



80-



60 -
S/ y=10.2+27.6*(1-exp(-42.3*x))+55.7*(1-exp(-3.6*x))
SR/ R2=0.81

40 -



20



0
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)

Figure 2.19. Eucalyptus amplifolia response to imazapyr concentration in soil 10 WAP
(weeks after planting) immediately after imazapyr application for experiment
2. Means of 4 replications present with standard error.







40






100



80 -



60



R2=0.92
40-



20 09

20


0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)

Figure 2.20. Eucalyptus grandis response to imazapyr concentration in soil 10 WAP
(weeks after planting) immediately after imazapyr application for experiment
2. Means of 4 replications present with standard error.







41






100



80 -



S60


.1 0 / y=14.6+77.4*(1-exp(-4.6*x))
40 R2=0.82



20 -

0


0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)

Figure 2.21. Panicum virgatum (switchgrass) response to imazapyr concentration in soil
10 WAP (weeks after planting) immediately after imazapyr application for
experiment 2. Means of 4 replications present with standard error.












Table 2.1. Species used in revegetation study in Citra, Florida.

common name scientific name size of seedlings


broomsedge
mimosa
sand live oak
bluejack oak
wiregrass
silkgrass
gopher apple

wax myrtle


lovegrass

longleaf pine

switchgrass
Eucalyptus grandis
Eucalyptus amplifolia


Andropogon virginicus
Mimosa strigillosa
Quercus geminata
Quercus incana
Aristida beyrichiana
Pityopsis graminifolia
Licania michauxii


Myrica cerifera


Eragrostis spectabilis

Pinus palustris

Panicum virgatum
Eucalyptus grandis
Eucalyptus amplifolia


10 centimeter tublings
10 centimeter pots
1 liter pots
1 liter pots
10 centimeter tublings
10 centimeter tublings
5 centimeter cups
2.5 centimeter x 7.5
centimeter (tray)
10 centimeter tublings
2.5 centimeter x 7.5
centimeter (tray)
10 centimeter tublings
15 centimeter tublings
15 centimeter tublings













Table 2.2. The effect of imazapyr soil concentration on percent mortality of selected revegetation species 10 weeks after planting.
Experiment 1 initiated on June 22, 2004, in Citra, FL. P60 values reflect the predicted imazapyr concentration that would result in less
than 60% mortality.


Plant Species Regression Equation
Eucalyptus amplifolia y=(-5518.4)+5614.4*exp(-0.0062*x)
mimosa y=101.3*exp(-1.1*x)
longleaf pine y=96.1*exp(-2.0*x)
Eucalyptus grandis y=5.2+88.8 *exp(-2.5 *x)
silkgrass y=10.1+55.3*exp(-3.6*x)
wiregrass y=1.8+56.8*exp(-3.6*x)
sand live oak y=25.2+22.7*exp(-6.3*x)
broomsedge y=43.3 *exp(-20.5 *x)+27.6*exp(-0.15 *x)
gopher apple y=15.5+38.6*exp(-7.7*x)
lovegrass y=(-1.9)+59.0*exp(-7.9*x)
bluejack oak y=41.2*exp(-4.7*x)
switchgrass y=10.9+34.9*exp(-39.0*x)
wax myrtle y=35.6*exp(-4.9*x)
Species exhibits greater than 60% mortality at all rates of imazapyr in


R"

0.78
0.99
0.97
0.87
0.65
0.68
0.18
0.60
0.65
0.95
0.85
0.59
0.47
soil.


P60 imazapyr values (kg ai/ha)
> 1.12
0.82
0.443
0.381
0.17
0.11
0.066
0.058
0.058
0.041
0.0044
0.0043
*












Table 2.3. The effect of imazapyr soil concentration on percent mortality of selected revegetation species 10 weeks after planting.
Experiment 2 initiated on July 21, 2004, in Citra, FL. P60 values reflect the predicted imazapyr concentration that would
result in less than 60% mortality.
Plant Species Regression Equation R2 P60 imazapyr values (kg ai/ha)
Eucalyptus amplifolia y=93.7+(-58.5)*x+14.7*xA2 0.75 > 1.12
mimosa y=88.8+10.0*exp(-3.7*x) 0.26 > 1.12
Eucalyptus grandis y=98.2+(-6.3)*x+(-16.9)*xA2 0.81 > 1.12
gopher apple y=69.5+6.2*x 0.12 > 1.12
wiregrass y=92.3+(-12.9)*x+(-53.9)*xA2 0.90 0.974
silkgrass y=(-501.5)+577.9*exp(-0.09*x) 0.67 0.773
switchgrass y=95.7+(-81.3)*x+(-3.2)*xA2 0.67 0.739
broomsedge y=(-1177.7)+1240.1*exp(-0.04*x) 0.31 0.544
sand live oak y=37.5+16.0*exp(-2.7*x) 0.05 0.437
lovegrass y=87.8+(-192.9)*x+104.9*xA2 0.96 0.325
bluejack oak NS
longleaf pine y=38.7*exp(-1.6*x) 0.78 *
wax myrtle y=39.9+(-105.9)*x+74.2*xA2 0.63 *
*Species exhibits greater than 60% mortality at all rates of imazapyr in soil.












Table 2.4. The effect of imazapyr soil concentration on percent injury of selected revegetation species 10 weeks after planting.
Experiment 1 initiated on June 22, 2004, in Citra, FL. 130 values reflect the highest predicted imazapyr concentration that
would cause no greater than 30% injury.
Plant Species Regression Equation R2 130 imazapyr values (kg ai/ha)
Eucalyptus grandis y=34.2*(1-exp(-23.7*x))+61.1*(1 -exp(-2.9*x)) 0.97 0.063
Eucalyptus amplifolia y=86.0*(1-exp(-8.5*x)) 0.97 0.056
mimosa y=42.8*(1-exp(-17.5*x))+69. 1*(1-exp(-0.9*x)) 0.96 0.055
switchgrass y=90.6*(1-exp(-9.9*x)) 0.94 0.037
broomsedge y=87.9*(1-exp(-24.7*x)) 0.87 0.014
silkgrass y=91.3*(1-0.0A*x)) 0.67 0.012
wiregrass y=86.2*(1-exp(-21.8*x)) 0.21 *
*Species exhibits greater than 30% injury at all rates of imazapyr in soil.












Table 2.5. The effect of imazapyr soil concentration on percent injury of selected revegetation species 10 weeks after planting.
Experiment 2 initiated on July 21, 2004, in Citra, FL. 130 values reflect the highest predicted imazapyr concentration that
would cause no greater than 30% injury.
Plant Species Regression Equation R2 130 imazapyr values (kg ai/ha)
Eucalyptus grandis y=6.1+85.8*(1-exp(-5.5*x)) 0.92 0.066
switchgrass y=14.6+77.4*(1-exp(-4.6*x)) 0.82 0.041
wiregrass y=5.5+22.8*(1-exp(-60.4*x))+63.5*(1-exp(-2.6*x)) 0.97 0.034
Eucalyptus amplifolia y=10.2+27.6*(1-exp(-42.3*x))+55.7*(1-exp(-3.6*x)) 0.81 0.024
mimosa y=12.9+67.5*xA0.33 0.74 0.017
silkgrass y=27.5+59.9*xA0.5 0.75 *
broomsedge y=39.2+45.3*(1-exp(-5.9*x)) 0.41 *
*Species exhibits greater than 30% injury at all rates of imazapyr in soil.














CHAPTER 3
IMAZAPYR RESIDUAL MEASUREMENTS USING CORN ROOT BIOASSAY

Introduction

Cogongrass [Imperata cylindrica (L.) Beauv.], an aggressive perennial grass

species which infests over 500 million hectares worldwide, is considered the world's

seventh worst weed (Holm et al. 1977). In the United States, cogongrass infests several

hundred thousand acres and it is widely spread throughout Florida and much of southern

Alabama and Mississippi (Johnson et al. 1999). Cogongrass can usually be found in

predominately non-agricultural settings in the United States., and this aggressive weed

tends to spread over vast areas where vegetation is marginally supported, suppressing and

displacing many native plants (Bryson and Carter 1993). Cogongrass tolerates a wide

range of soil conditions but appears to grow best in soils with acidic pH, low fertility, and

low organic matter. Several survival strategies lend to this invasive plant's ability to

spread and persist, including an extensive rhizome system, adaptation to poor soils,

drought tolerance, fire adaptability, and high genetic plasticity (Holm et al. 1977, Dozier

et al. 1998).

Current control methods for cogongrass rely heavily on chemical treatment, which

unfortunately provides limited long-term control unless used in conjunction with

revegetation. The most effective herbicides for cogongrass management are glyphosate

and imazapyr (Dozier et al. 1998; Barnett et al. 2000; MacDonald et al. 2002). Imazapyr

is used to control annual and perennial weeds, deciduous trees, and vines in rights-of-way

and other noncropland areas, as well as in forestry as a conifer releasing agent (Anon.









2002). The mode of action of imazapyr, a member of the imidazolinone family of

herbicides, involves the inhibition of acetohydroxyacid synthase (AHAS), which is

needed for synthesis of branched chain amino acids (Shaner 1991). Field half-life values

range from 25-142 days depending on soil type and environmental conditions, with soil

adsorption increasing as organic matter and clay content increase (Anon. 2002).

Imazapyr is relatively harmless to animals and has minimal off-target impacts if used

correctly (Mangels 1991).

Compared to glyphosate, imazapyr generally provides control for a longer period of

time due to soil activity (MacDonald et al. 2002), and research to date has indicated

imazapyr at 1.12 kg-ai/ha applied late summer/early fall provides control for as long as

18 months (Dozier et al. 1998). Burning prior to herbicide application has also proven

effective, with benefits including weakened rhizomes due to re-allocation of starch

reserves to new shoot growth and removal of old biomass. Herbicide application to the

regrowth of new plant tissues maximizes absorption and results in greater efficacy

(Johnson et al. 1999).

Although there is ample information on the effect of several herbicides on weedy

species, little information regarding the herbicide tolerance (i.e., selectivity potential) of

native species is available. In previous research by Miller et al. (2002), several native

species were evaluated under greenhouse conditions for response to imazapyr. Imazapyr

caused severe injury to most species, but this injury was reflected to a foliar application

only. In practical field situations, herbicides are usually sprayed to control cogongrass

with little or no subsequent implementations such as revegetation. These areas often

become reinfested because of a lack of suppressive cover.









An important step in the further suppression of cogongrass is to establish a native

plant cover into these sprayed areas as soon as the residual herbicide levels in the soil

become tolerable to the plant. It is important to quantify these soil residual levels to best

predict effective revegetation timing in order to effectively suppress cogongrass. One of

the more popular tools for monitoring imidazolinone residues is through soil bioassay.

Corn is highly sensitive to imidazolinone and sulfonylurea herbicides and has become the

accepted bioassay species for the detection of these herbicides in soil (O'Bryan 1994).

By using corn bioassay techniques, an understanding of plant species' response to

imazapyr residues in soil can be obtained. With these data, a prediction model can be

calculated to determine how long it takes imazapyr levels in soil to reach a concentration

that will be tolerable to the plant in question. This information will ultimately be

beneficial for restoration purposes in southeastern ecosystems (MacDonald et al. 2002).

Soil type plays an important role in residual herbicide levels due to its structure and

content of clay and organic matter. In sandy soils, there are fewer charged sites that the

herbicide can adsorb to, and leaching occurs more often. Therefore, sandy soils contain

less residual matter after a given period of time than a clay soil, which has a much greater

affinity for adsorption. Herbicides also tend to persist longer in loamy and silty soils due

to less leaching compared to sandy soils.

In central Florida, reclaimed mining sites have a diverse collection of soil types

with overburden, sand tailings and phosphatic clay pits being three of the most

prominent. Overburden, a mixture of sand and clay, is removed from the land surface to

the top of the ore body and piled on the side. Overburden shows the highest variability in

soil texture, soil color and soil chemical parameters (Segal et al. 2001). This soil type is









on average composed of 80% sand, 8% silt, and 12% clay with a pH of 5.8.1 Overburden

has slightly greater clay and silt content, higher water-holding capacity, and greater P and

K content than native Floridian soils, which may give aggressive weeds a competitive

advantage over slower-growing natives (Richardson et al. 2003). The phosphate ore

currently being mined is an unconsolidated mixture of sand, clay, and phosphate mineral.

The sand tailings are separated from this ore and hydraulically pumped to fill mine cuts

between overburden piles. Although sand tailings are usually nutrient-poor and drought

compared with these three other soil types (Segal et al. 2001), they have higher P and K

contents and slightly coarser grain sizes than native soils (Kluson et al. 2000).

Phosphatic clay is washed from phosphate ore and pumped, at about 3-5% solids, to

settling areas. This clay commonly has pH values near 7.5, while some older sites with

good forest cover and higher organic matter have pH values near 6.8. This soil type

covers about 40% of the mined area and is considered highly fertile (Stricker 2000).

Imazapyr provides good control of cogongrass but has limited utility due to the

long residual effects of this compound, which could hinder revegetation strategies. Initial

research indicates the residual activity of this compound may be less than theorized,

allowing for more flexibility in a revegetation scheme. Because of the diversity of soils

in Florida, as well as much of the U.S., an understanding of herbicide persistence as a

function of soil type would be important to predict the best time for revegetation. By

taking samples of the three distinct types of soil after a certain amount of time after

herbicide application, information on residue amounts can be generated. With such


1 Richardson, S.G. 2004. Personal Communication.









residual data, a timetable could be calculated to best predict when revegetation should

occur.

Materials and Methods

Research was conducted at Tenoroc Fish Management Area, a 2,430-hectare tract

of land that was mined for phosphate until the mid-1970's. The area is located 3.2

kilometers northeast of Lakeland, Florida. Approximately 4000 hectares of lakes locally

referred to as "phosphate pits" remained from early mining operations. This area has

three distinct soil types that were results of the mining process: sand tailings, overburden,

and phosphatic clay settling ponds. Studies were conducted on each of the three soil

types to gain better understanding of imazapyr persistence in each of these areas.

In each of the three soil types, a total area of 24 x 30 meters was mowed in October

2002, immediately before herbicide application. The plots measured 6 x 6 meters in a

randomized complete block design with 5 replications. Treatments were applied using a

CO2 backpack sprayer with 11002 flat fan nozzles calibrated to deliver 187 L/ha. The

treatments were 0.84, 1.68, and 3.36 kg ai/ha imazapyr2 with an untreated check. Both

the overburden and sand areas were sprayed on November 19, 2002, while the clay

settling area was sprayed December 12, 2002. Within each plot for all 3 areas, a total of

10, 2.5-cm diameter, 15-cm deep soil cores were randomly taken. Sampling occurred

immediately prior to application, immediately after application, and at 1, 3, 6, and 12

months after application. Samples were put in labeled plastic freezer bags and placed on


2 Arsenal 4 Applicators Concentrate (AC), BASF, USA.









ice for transport to Gainesville. These soil samples were stored frozen at -200C until

bioassay work was performed.

Imazapyr concentration was determined using a corn-root bioassay, which was

conducted in the greenhouse at the Gainesville campus. Individual frozen soil samples

from each location were thawed, dried, and equally distributed into 3 cone shaped vessels

(Cone-tainers, 40 x 200 mm)3 which were used as growth containers.

Each bioassay experiment was conducted with an accompanying series of imazapyr

concentrations which allowed for the development of a standard response curve. To

develop this curve, untreated soil from each of the three locations was sifted through a

2mm screen and air dried for 3 days. Soils were put in small pots (10 x 15 cm) to

simulate the surface area of the previous field sampling. Known amounts of imazapyr

were applied to the samples using a C02 backpack sprayer with 11002 flat fan nozzles

calibrated to deliver 187 L/ha. For these standards, a wide range of imazapyr rates were

applied: 0.0, 0.018, 0.036, 0.071, 0.14, 0.28, 0.56, and 1.12 kg ai/ha. This was

performed because imazapyr in the original field samples would decrease as the sampling

continued over time. Having lower concentrations in the standard response curve

component would aid in accuracy of predicted concentration. After imazapyr rates were

sprayed, treated soil was equally mixed in a plastic bag and similarly divided into 3

Cone-tainers.

Seeds of field corn4 were pre-germinated by placement under wet paper towels for

2-3 days. For all field and standard samples, one pre-germinated corn seed (radical



3 Cone-Tainer Nursery, 150 North Maple, Canby, OR 97013.

4 Pioneer 33J 56.









length approximately 0.5 cm) was planted 2 cm below the soil surface. The soil-filled

cone-tainers were immediately subirrigated to field capacity and then placed in a

greenhouse environment of 16 hours daylight and 8 hours darkness at 300C mean

temperature. After 9 days, corn seedlings were removed, washed, and primary root

length measured. Regression equations were calculated to best fit the recorded data.

Results and Discussion

Only 0, 1 and 3 month after treatment (MAT) soil samples were successfully

utilized using corn root bioassay. Standard curves were calculated each time a bioassay

was performed and are shown in the Appendix. These generated regression equations are

shown on each graph, along with adjusted R2 values. Corn root data were fitted to the

corresponding regression equations and the predicted values of imazapyr in the soil are

listed in Tables 3.1, 3.2, and 3.3.

In all three areas sprayed, detected residues were substantially lower than expected.

This can especially be seen in the 0 MAT data, where significantly low levels of

imazapyr were detected immediately after application. This could be due to a dense

vegetative cover found in the areas during herbicide application, which might have

prevented imazapyr from fully reaching the soil surface. Vegetative cover, either as dead

biomass or thatch, is common in areas chemically treated for cogongrass. This might be

beneficial in revegetation planning since soil imazapyr residues might be lower than

expected due to this foliar uptake.

Sand tailing data for all samples taken at 0, 1, and 3 MAT were averaged and

replications were combined. This combined data are shown in Table 3.1. At the lowest

application rate of 0.84 kg ai/ha, the soil samples average a consistently similar rate at 0

MAT. At 1 MAT of the 0.84 kg ai/ha, there was no detection of imazapyr, and a trace









amount was detected at 3 MAT (0.003 kg ai/ha). In the areas sprayed with 1.68 and 3.36

kg ai/ha, 1.12 kg ai/ha were predicted for sand tailings at 0 MAT. Since the maximum

rate of the standards was 1.12 kg ai/ha, no greater value could be comparatively

quantified. For 1 MAT, predicted imazapyr values were 0.011 and 0.026 kg ai/ha for the

1.68 and 3.36 kg ai/ha sand tailing applications. In the 1.68 kg ai/ha areas, imazapyr

rates were reduced at 3 MAT (0.003 kg ai/ha). For the replications treated with 3.36 kg

ai/ha, a reduction was seen 3 MAT (0.0087 kg ai/ha).

In the clay soil, higher concentrations of imazapyr than in the sand tailings area

were detected 3 MAT in the areas treated with 1.68 and 3.36 kg ai/ha (Table 3.2). For all

treatments, samples taken 0 MAT were similar in value (0.062, 0.064, and 0.054 kg ai/ha

for the plots sprayed with 0.84, 1.68, and 3.36 kg ai/ha, respectively). This inconsistent

data could be credited to the variability of the soil sampling techniques. Soil imazapyr

residues were continually reduced at 1 and 3 MAT for all treatments in the clay soil.

In the overburden soil, 0 MAT residues were greater than those of the clay and

less than those in the sand area (Table 3.3). For the area sprayed with 0.84 kg ai/ha,

residues decreased to 0.018 kg ai/ha 1 MAT and 0.01 kg ai/ha 3 MAT. The plots treated

with 1.68 kg ai/ha also decreased to 0.027 kg ai/ha 1 MAT and 0.015 kg ai/ha 3 MAT.

Finally, plots treated with 3.36 kg ai/ha were reduced to 0.033 kg ai/ha 1 MAT and 0.025

kg ai/ha 3 MAT.

Overall, imazapyr concentration was more quickly reduced in sand tailings. Mixed

results occur between clay and overburden soil. This overall decreased concentration of

imazapyr in the soil is expected, and the different rates and change with concentrations

among soil types are useful data for selecting successful revegetation species.









These bioassay data, coupled with the plant species injury and mortality data from

Chapter 2, were used to create a timetable to best estimate optimal planting dates per

species. The dates reflect the estimated time it takes for imazapyr residues in soil to

decrease to a tolerable level for the plants. Estimated time intervals are expressed in

months after treatment (MAT) and were estimated from the predicted P60 and 130 values

for each species. These data are based on an imazapyr application rate of 0.84 kg ai/ha

and are shown in Tables 3.4 and 3.5 (Experiment 1 and 2, respectively). Regression

figures and equations are also shown in the Appendix.

As seen in Table 3.1, no correlation can be found among the measurements taken in

the sand area sprayed with 0.84 kg ai/ha imazapyr. This is because imazapyr was not

detected 1 MAT, yet trace amounts were detected 3 MAT. For this reason, only

estimations for clay and overburden areas were formulated. In both the clay and

overburden area in Experiment 1, six species can be planted immediately after imazapyr

application and expect to show at least a 40% survival rate 10 WAP (P60). These species

are E. amplifolia, mimosa, longleaf pine, E. grandis, silkgrass, and wiregrass. Sand live

oak, broomsedge, and gopher apple show some sensitivity, therefore at least one month

should be waited before planting. Lovegrass should be planted at least one month after

treatment, while bluejack oak and switchgrass have significantly longer times of 3 MAT

to allow for at least 40% survival. Since wax myrtle showed greater than 60% mortality

at all imazapyr rates in both experiments, no predicted plantback date could be given

within the limit of 60 days. In Experiment 2, all plant species show at least 40% survival

in both soil types immediately after application. In addition to wax myrtle, switchgrass









shows greater than 60% mortality at all rates in Experiment 2, therefore no date could be

predicted.

Predicted dates according to injury data from Chapter 2 (I30 values) are listed for

the seven monitored species for Experiment 1 and 2, as well. In Experiment 1 (Table

3.4), E. grandis can be planted 1 MAT in clay and 1 MAT in overburden to exhibit no

more than 30% injury 10 WAP. E. amplifolia, mimosa, and bluejack oak also show

slightly longer time periods for 130 predictions in overburden soils as compared to clay

soils. Silkgrass and broomsedge have the longest delay in planting until soil residues are

within range of 130 values (3 MAT in clay and 3 MAT in overburden). Wiregrass shows

at least 30% injury at all rates of imazapyr, so no predicted date could be made within the

range of 60 days. Experiment 2 (Table 3.5) shows similar predicted dates according to

130 values for E. grandis and switchgrass, although E. amplifolia, mimosa, and wiregrass

show increased predicted plantback time (MAT) in which soil residues cause no more

than 30% injury in both clay and overburden areas. These extended dates are in contrast

with those for silkgrass and broomsedge, in which all rates of imazapyr caused at least

30% injury in Experiment 2. Therefore, no predicted dates could be made for these

species since the study range was only 60 days.

Based on the plant-back time in relation to injury data, E. grandis and switchgrass

are good candidates for use in revegetation planning. Several additional species,

including E. amplifolia, mimosa, longleaf pine, silkgrass, and wiregrass, would be good

choices in a plantback scenario if percent mortality is a more desirable quality than

injury. These predicted plantback dates after initial imazapyr application will be helpful

in determining optimum timing of a revegetation project. Knowing what species will






57


best tolerate imazapyr and how long to wait before planting can reduce the gap of time

between initial cogongrass control and its reinvasion of an area.












Table 3.1. The predicted concentration values of imazapyr using a corn root bioassay
from sand tailings soil in Polk County.
Months after treatment
Application rate 0 1 1 2 3 3
----------- ------------------------ kg ai/ha --------------------------
0 0 0 0
0.84 0.84 + 0.334 0 0.003 0
1.68 1.12 + 0 0.011 + 0.01 0.003 0
3.36 1.12 + 0 0.026 + 0.01 0.0087 + 0.01
1 Values derived from regression equation y=2.3+12.3*exp (-26.7*x); R2= 0.87; See Figure A-1.
2 Values derived from regression equation y=1.7+13.6*exp (-28.9*x); R2=0.95; See Figure A-2.
3 Values derived from regression equation y=2.0+10.8*exp (-44.0*x); R2=0.97; See Figure A-3.
4 Mean of 5 replications followed by Standard Deviation.

Table 3.2. The predicted concentration values of imazapyr using a corn root bioassay
from clay soil in Polk County.
Months after treatment
Application rate 0 1 1 2 3 3
----------- ------------------------ kg ai/ha ------------------------------
0 0 0 0
0.84 0.062 0.014 0.013 + 0.01 0.0018 0
1.68 0.064 + 0.02 0.044 + 0.01 0.023 0.02
3.36 0.054 + 0.02 0.032 + 0.02 0.02 0.02
1 Values derived from regression equation y=1.7+15.2*exp(-40.5*x); R2= 0.83; See Figure A-4.
2 Values derived from regression equation y=1.4+16.4*exp(-36.7*x); R2=0.97; See Figure A-5.
3 Values derived from regression equation y=1.5+12. l*exp(-23.3*x); R2=0.90; See Figure A-6.
4 Mean of 5 replications followed by Standard Deviation.







59


Table 3.3. The predicted concentration values of imazapyr using a corn root bioassay
from overburden soil in Polk County.
Months after treatment
Application rate 0 1 2 3 3
----------------------------------- kg ai/ha --------------------------
0 0 0 0
0.84 0.29 + 0.294 0.018 + 0.01 0.01 0.01
1.68 0.17 + 0.17 0.027 + 0.02 0.015 + 0.01
3.36 0.36 + 0.36 0.033 0.01 0.025 0.02
1 Values derived from regression equation =2.0+12.6*exp(-28.3*x); R2= 0.95; See Figure A-7.
2 Values derived from regression equation y =1.6+11.8*exp(-33.0*x); R2=0.94; See Figure A-8.
3 Values derived from regression equation y =0.9+12.7*exp(-32.7*x); R2=0.93; See Figure A-9.
4 Mean of 5 replications followed by Standard Deviation.












Table 3.4. Estimated revegetation timeframe as related to plant species and soil type according to Experiment 1.
Clay Overburden
P40 Mortality 130 Injury P40 Mortality 130 Injury
Plant Species --------------Months after imazapyr application (0.84 kg ai/ha) in soil-------------
Eucalyptus amplifolia 0 1 0 1
mimosa 0 1 0 1
longleaf pine 0 -- 0 --
Eucalyptus grandis 0 1 0 1
silkgrass 0 3 0 3
wiregrass 0 0 *
sand live oak 1 -- 1 --
broomsedge 1 3 1 3
gopher apple 1 -- 1 --
lovegrass 1 -- 1 -
bluejack oak 3 -- 3 --
switchgrass 3 1 3 1
wax myrtle -
* Time for imazapyr rate to become tolerable at the specified value exceeds period of monitoring.













Table 3.5. Estimated revegetation timeframe as related to plant species and soil type according to Experiment 2.
Clay Overburden
P40 Mortality 130 Injury P40 Mortality 130 Injury
Plant Species -------------Months after imazapyr application (0.84 kg ai/ha) in soil-------------
Eucalyptus amplifolia 0 1 0 1
mimosa 0 3 0 3
longleaf pine 0 -- 0 --
Eucalyptus grandis 0 1 0 1
silkgrass 0 0 *
wiregrass 0 1 0 1
sand live oak 0 -- 0 --
broomsedge 0 0 *
gopher apple 0 -- 0 -
lovegrass 0 -- 0 -
bluejack oak 0 -- 0 -
switchgrass 1 1
wax myrtle -
*Time for imazapyr rate to become tolerable at the specified value exceeds period of monitoring.














CHAPTER 4
NATURAL RECRUITMENT OF PLANT SPECIES IN AREAS PREVIOUSLY
INFESTED WITH COGONGRASS

Introduction

Cogongrass [Imperata cylindrica (L.) Beauv.] is a rhizomatous perennial grass

species found throughout much of the tropical and sub-tropical regions of the world and

is considered to be the world's seventh worst weed (Holm et al. 1977). Unfortunately,

the occurrence of cogongrass has increased drastically during the past twenty years

(Bryson and Carter 1993) and is currently reported in much of the southeast United

States, including Florida, Mississippi, and Alabama (Johnson et al. 1999). Cogongrass

tends to spread over vast areas where vegetation is marginally supported, suppressing and

displacing many native plants (Bryson and Carter 1993). Cogongrass is able to spread

and persist through several survival strategies including an extensive rhizome system,

adaptation to poor soils, drought tolerance, prolific wind disseminated seed production,

fire adaptability, and high genetic plasticity (Holm et al. 1977; Dozier et al. 1998).

Invasive, non-native weeds such as cogongrass are a cause for concern in natural

areas within the United States. Once aggressive weeds such as this become established in

an area, they may continue to proliferate and displace most of the native vegetation, many

times resulting in a monoculture of cogongrass (Shilling et al. 1997). Invasive weeds can

displace native plants by growing and reproducing more rapidly and being less sensitive

to environmental stresses than native species (Marion 1986). Native xeric scrub and sand

hill species commonly found throughout Florida typically grow slowly and provide low









coverage. This is due to low moisture and fertility inherent in xeric soils, which allows

for an open niche for invasive species (Segal et al. 2001). Once an invasive species

dominates an area, natural fire and hydrology processes that influence the ecosystem may

be altered. There is often less pressure placed upon these non-native species from

disease, insects, or predation since they did not naturally evolve in these areas. Non-

native invasive plants are often able to thrive when outside pressures are removed.

In Florida, reclaimed phosphate mining areas are important areas for cogongrass

control and native plant restoration. Because mining disturbance creates a hospitable

environment for weed invasion, one of the most difficult barriers to successful restoration

is the control of cogongrass and other invasive weeds. In central Florida, reclaimed

mining sites have a diverse collection of soil types with overburden, sand tailings and

phosphatic clay pits being three of the most prominent (Richardson et al. 2003).

Overburden, a mixture of sand and clay, is removed from the land surface to the top of

the ore body and piled on the side. Phosphate ore, currently being mined, is an

unconsolidated mixture of sand, clay, and phosphate mineral. Sand tailings are separated

from the phosphatic ore and hydraulically pumped to fill mine cuts between overburden

piles. Phosphatic clay is washed from phosphate ore and pumped, at about 3-5% solids,

to settling areas. This soil type covers about 40% of the mined area and is considered

highly fertile (Stricker 2000).

These three soil types involved in phosphate mining processes are highly diverse in

nature, yet they are all susceptible to cogongrass and other non-native weed invasions.

This is due to the disturbance of the areas during the mining process and the associated

harsh conditions to which plants are subjected.









In phosphate reclamation areas and other natural areas, chemical weed control is

the most common practice. Unfortunately, these herbicide control methods provide

limited long-term control. To date, the most effective herbicides for cogongrass

management are glyphosate and imazapyr (Dozier et al. 1998; Barnett et al. 2000;

MacDonald et al. 2002). Generally, imazapyr provides control for a longer period of

time due to soil activity and has minimal off-target effects if used correctly (MacDonald

et al. 2002). Research to date has indicated imazapyr at 1.12 kg-ai/ha applied late

summer/early fall provides control for as long as 18 months (Dozier et al. 1998). The

main reason for this limited control is the presence of cogongrass rhizomes, which can

comprise over 2/3 the total plant biomass. These rhizomes contain multiple nodes from

which regrowth may occur, but generally only a fraction sprout at any given time

(English 1998). This low shoot to root/rhizome ratio contributes to its rapid regrowth

after cutting or burning (Sajise 1976). Cogongrass rhizomes are white and tough with

shortened internodes. Specialized anatomical features help to conserve water within the

central cylinder and help to resist breakage and disruption when trampling or disturbance

occurs (Holm et al. 1977). Rhizomes are predominately found within the top 15 cm of

fine textured soils or the top 40 cm of course textured soils. However, rhizomes have

been discovered growing at depths of 120 cm (Holm et al. 1977; Gaffney 1996).

According to Tominaga (2003), cogongrass rhizomes can be grouped in the following

three categories: tillering, secondary colonizing, and pioneer rhizomes. Unlike

cogongrass seedlings, which are defined as R-strategist (ruderal) and invade open patches

in disturbed habitats, rhizomes from current cogongrass stands are more defined as C-

strategist (competitor) that can persist in established populations (Tominaga 2003).









These rhizomes provide a tremendous amount of biomass for regeneration after foliar

loss, with one study showing rhizome length of over 89 meters within one square meter

of soil surface area (Lee 1977).

Cogongrass rhizomes are a major hindrance to continued suppression after initial

control. For long-term management of cogongrass, further methods need to be integrated

into the traditional control techniques that are currently used. Even in areas where initial

control has been successful, cogongrass re-infestation will often occur. One objective of

this study is to determine rhizome presence and density in areas previously treated with

imazapyr and glyphosate, which will be helpful in understanding the mechanism of

cogongrass re-infestation. In addition, the objective of monitoring natural recruitment of

native species in areas previously treated with these herbicides may help us to understand

which plant species are more competitive with cogongrass. This type of information will

be beneficial in the long-term planning and management of natural areas for long-term

cogongrass management and control.

Materials and Methods

Research was conducted at Tenoroc Fish Management Area, a 2,430-hectare tract

of land that was mined for phosphate until the mid-1970's. The area is located 3.2

kilometers northeast of Lakeland, Florida. Approximately 400 hectares of lakes locally

referred to as "phosphate pits" remain from early mining operations.

Three areas previously infested with cogongrass were sprayed in the fall of 2000,

2001, and 2003, following a late summer (August) burn. Burning removed accumulated

thatch and simulated regrowth. Cogongrass was 30-45 cm tall at the time of treatment.









Long Term Cogongrass Control

Treatments included imazapyr at 0.84 kg ai/ha and glyphosate at 3.36 kg ai/ha in 76

m long x 15 m wide plots with 4 replications. In January 2004, visual observations were

taken in these areas to monitor cogongrass reinfestation 0.25, 2, and 3 years after initial

treatment to determine which herbicide had the greatest control over time. Percent

control was recorded, where 0 = no control and 100 = complete control. Data were

subjected to analysis of variance to test for main effects and interactions.

Rhizome Distribution

In the area sprayed on October 16, 2000, 25 samples of 10 cm x 20 cm soil cores

were taken from each of the 8 plots, approximately 3 years post-treatment (January 13,

2004). The samples were taken at random locations within each plot and categorized

according to proximity to cogongrass regrowth: 1) samples where no cogongrass was

present within 0.6 meters; 2) samples within 0.6 meters of cogongrass; and 3) samples

within a cogongrass patch. This sampling date was chosen after several growing seasons

to allow for any natural progression of annual and perennial species that might establish

after initial cogongrass control. Soil samples were transported back to Gainesville, FL,

for rhizome removal. After 3 days in an oven drier at 60C, rhizome dry weight was

determined. Plant species were evaluated for percent cover within each plot, where 0 =

no coverage and 100 = complete coverage, and data were subjected to analysis of

variance to test for main effects and interactions.

Native Species Recolonization

In addition, the Tenoroc area has three distinct soil types that result from the

mining process: sand tailings, overburden, and phosphatic clay settling ponds. Mowing

occurred in October 2002 in each of the three soil types immediately before herbicide









application, with treatments including 0.0, 0.84, 1.68, and 3.36 kg ai/ha imazapyr. Plot

size was 6 m x 6 m with 5 replications in a randomized complete block design.

Treatments were applied using a C02 backpack sprayer with 11002 flat fan nozzles

calibrated to deliver 187 L/ha. Both the overburden and sand areas were sprayed on

November 19, 2002, while the clay settling area was sprayed December 12, 2002. In

each of these three soil types, native species recolonization was observed in January 2004

(approximately 2 years after treatment) among the 3 imazapyr rates applied. All data

were subjected to analysis of variance to test for main effects and interactions, and means

separated using Fisher's LSD procedure at the 0.05 level.

Results and Discussion

Long Term Cogongrass Control

Table 4.1 shows percent cogongrass control in each of the previously sprayed areas

in Polk County, Florida. Since these observations were made in January 2004, this table

represents observations taken 4, 39, and 48 months after treatment (MAT) from separate

sites. In the area sprayed in 2003, there was a significant difference between glyphosate

and imazapyr plots (62 and 96% cogongrass control, respectively). There was also

significant difference in the areas sprayed in 2001, 36 MAT (37% control in glyphosate

plots and 88% control in imazapyr plots). These data show that up to 36 MAT, areas

treated with 0.84 kg ai/ha imazapyr continue to provide statistically greater control of

cogongrass than those treated with 3.36 kg ai/ha glyphosate. As time progressed to 48

MAT, there was no statistical difference between treatments. This continued control of

cogongrass in imazapyr areas does not imply that imazapyr provides increased control as

time progresses. The data might reflect differences in consistency with glyphosate

control as seen in the difference in control with glyphosate between 2001 and 2000.









Also, the data possibly suggest that initial higher control of cogongrass with imazapyr

compared to glyphosate possibly allowed for other species to enter the area and compete

with the cogongrass as regrowth occurred.

Thirty nine MAT, there was no significant difference between herbicides in overall

cogongrass control or the density of the 3 most commonly observed native species-

dogfennel (Eupatorium capillifolium), broomsedge (Andropogon virginicus), and

saltbush (Baccharis halimifolia), as shown in Table 4.2.

Rhizome Distribution

Both glyphosate and imazapyr plots had approximately half of all samples

classified as category 1- no cogongrass within 0.6 meters, (52 and 56%, respectively) as

shown in Table 4.3. Of these samples, only an average of 1.5% contained rhizomes, with

low average weights (0.19g and 0.08g in glyphosate and imazapyr treatments.) Both

herbicide treatments contained an average of 38% category 2 samples- cogongrass within

0.6 meters, with approximately half of these samples containing rhizomes with average

weights of 0.9g and 0.38g, respectively (Table 4.4). Only 9 and 6% of glyphosate and

imazapyr samples were classified as category 3- cogongrass present within core samples

(Table 4.5). Of these samples, 100% contained rhizomes with average weights of 2.2g

and 2.0g, respectively. These data help to support the hypothesis that the continued

growth and spread of cogongrass after treatment in 2000 was due to patches remaining

from initial control rather than regrowth from dormant rhizomes. This is because

rhizomes were predominately associated with foliar patches.

Native Species Recolonization

Vegetation percent cover at the two of the three soil types in Polk County sprayed

with imazapyr in 2002 was recorded. The third soil type was the clay settling pond area,









but no data could be reported due to a fire that moved through the area in the fall of 2003.

Due to the fire, all treatments in the clay area had cogongrass coverage averaging 100%.

Data for the sand tailing area and the overburden area are shown in Tables 4.6 and 4.7.

At the sand area in Polk County (Table 4.6), the most common species present was

the non-native P. notatum, which was present prior to treatment in 2002, followed by the

windblown species H. subaxillaris. There was no significant difference in percent cover

for either species among varying imazapyr rates. Rhynchelytrum repens, Passiflora

incarnata, Conyza canadensis, and cogongrass were also present, but with no statistical

difference among imazapyr rates, including the untreated plots. Since cogongrass was

still present in all imazapyr treated areas, it is not known if it spread from dormant

rhizomes in the plot or rhizome invasion from adjacent untreated areas.

In the overburden area, similar differences in imazapyr rates among all species is

shown in Table 4.7. The most common species was again the non-native P. notatum,

followed by R. repens, E. capillifolium, and Euthamia caroliniana, three species that

spread by windblown seeds. Leguminous species such as Indigofera hirsuta, Crotalaria

pallida, and Chamaecristafasciculata were also present within the overburden plots,

although at lower coverage. In related studies, legumes have shown tolerance in areas

treated with imazapyr and show an ability to suppress cogongrass due to competitiveness

(Akobundu et al. 2000; Gaffney 1996). A. virginicus, another wind-blown native species,

was present in the check plots where no imazapyr was sprayed, yet only at minimal

coverage.

Overall, results from these studies do not suggest there were significant long-term

effects on native plant recruitment due to imazapyr treatment. After 2 years, there was no






70


significant difference in native species growth in two soil types for all rates of imazapyr.

These data are helpful in understanding how a more effective revegetation strategy could

be developed as part of an overall integrated cogongrass management system.






71




Table 4.1. Cogongrass control over a 4-year period. Visual ratings taken in January
2004 in Polk County.


2003


2001


2000


kg ai/ha ------------------% cogongrass control--------------------


glyphosate

imazapyr


3.36

0.84


LSD 0.05


Table 4.2. The effect of glyphosate and imazapyr on native species 39 months after
application in Polk County (area sprayed in Fall 2000).


Eupatorium
capillifolium


Andropogon
virginicus


Baccharis
halimifolia


kg ai/ha --------------------------% cover------------------------------


LSD 0.05


Table 4.3. Category 1 soil samples- no cogongrass within 0.6 meters of core samples.
Rhizome data taken 39 months after herbicide application in Polk County.


Category 1 no cogongrass within 0.6 meters


kg % of all
ai/ha samples


% of samples with
rhizomes


average rhizome dry
wt.(g)


glyphosate 3.36
imazapyr 0.84


LSDo.os NS


glyphosate

imazapyr


3.36

0.84


0.19
0.08









Table 4.4. Category 2 soil samples- cogongrass within 0.6 meters of core samples.
Rhizome data taken 39 months after herbicide application in Polk County.

Category 2 -cogongrass within 0.6 meters


kg
ai/ha

glyphosate 3.36
imazapyr 0.84


% of all
samples


% of samples with
rhizomes


average rhizome dry
wt.(g)


0.38


LSDo.o5


Table 4.5. Category 3 soil samples- cogongrass present within core samples. Rhizome
data taken 39 months after herbicide application in Polk County.


Category 3 -cogongrass present


% of samples with
kg ai/ha % of all samples rhizomes
rhizomes


glyphosate 3.36
imazapyr 0.84


average rhizome dry
wt.(g)
2.2

2.0


LSDo.o5 NS













Table 4.6. Natural presence of species on sand soil type burned and treated with imazapyr (Arsenal) in the fall of 2002 at Tenoroc
WMA. Visual evaluations of percent cover were taken in fall of 2004 (24 months after treatment).


Rhynchelytrum
repens


Paspalum
notatum


Heterotheca
subaxillaris


imazapyr rate (kg ai/ha) ---------------------------------------% cover--------------------------------- ---


0.84

1.68

3.36


LSD 0.05


Passiflora
incarnata


Conyza
canadensis


cogongrass













Table 4.7. Natural presence of species on overburden soil type burned and treated with imazapyr (Arsenal) in the fall of 2002 at
Tenoroc WMA. Visual evaluations of percent cover were taken in fall of 2004 (24 months after treatment).


Rhynchelytrum Eupatorium
repens capilifolium


Euthamia
caroliniana


Paspalum
notatum


legume spp.1


Andropogon
virginicus


imazapyr rate (kg ai/ha)


--------------------------------------- -% cover----------------------------------- ---


0.84

1.68

3.36


LSD 0.05 NS NS NS
Including Indigofera hirsuta, Crotalaria pallida, and Chamaecristafasciculata.














CHAPTER 5
CONCLUSIONS

Cogongrass [Imperata cylindrica (L.) Beauv.] is a highly invasive grass species

found throughout much of the tropical and sub-tropical regions of the world, infesting

over 500 million hectares worldwide (Holm et al. 1977). Cogongrass can usually be

found in predominately non-agricultural settings in the United States, and spreads over

vast areas where vegetation is marginally supported, suppressing and displacing many

native plants (Bryson and Carter 1993).

Cogongrass tolerates a wide range of soil conditions but appears to grow best in

soils with acidic pH, low fertility, and low organic matter. This aggressive weed is able

to spread and persist through several survival strategies including an extensive rhizome

system, adaptation to poor soils, drought tolerance, prolific wind disseminated seed

production, fire adaptability, and high genetic plasticity (Holm et al. 1977; Dozier et al.

1998).

Current control methods for cogongrass rely heavily on chemical treatments which

provide limited long-term control due to the presence of multiple cogongrass rhizomes,

which can comprise over 2/3 the total plant biomass. Research to date has indicated

imazapyr at 1.12 kg ai/ha applied late summer/early fall provides control for as long as 18

months (Dozier et al. 1998). Burning prior to herbicide application helps to remove dead

biomass and promote new shoot growth, allowing for more effective control.

Unfortunately, cogongrass will re-form a monotypic stand within 1-2 years after this time

if additional treatments are not imposed (Dozier et al. 1998).









Imazapyr provides good control of cogongrass but has limited utility due to the

long residual effects of this compound, which could hinder revegetation strategies. An

important step in the further suppression of cogongrass is to establish a native plant cover

into these sprayed areas as soon as the residual herbicide levels in the soil become

tolerable to the plant. Plant response to imazapyr in soil is useful information in

determining which species would perform best in a plantback scenario. These studies

showed that both Eucalyptus species (E. grandis and E. amplifolia), Mimosa strigillosa,

Aristida beyrichiana, and Pityopsis graminifolia show low mortality response to

imazapyr in soil. However, E. amplifolia and E. grandis both show higher injury

response than many other species to imazapyr in this study. The data show that these

species might be able to "outgrow" the imazapyr injury after some period of time. Even

though a plant might show initial injury symptoms, the overall ability of that plant to

recover is a very important quality to look for in a potential revegetation species.

Another concern with revegetation is the amount of imazapyr residues in different

soils. Soil type has an important influence on the residual amount of herbicide due to the

soil structure and content of clay and organic matter. Central Florida is home to many

reclaimed mining sites which have a diverse collection of soil types, with overburden,

sand tailings and phosphatic clay pits being the most prominent. These three soil types

involved in phosphate mining processes are highly diverse in nature, yet they are all

susceptible to cogongrass and other non-native weed invasions. This is due to the

disturbance of the areas during the mining process and the associated harsh conditions to

which plants are subjected. Because of this diversity of soils in Florida, as well as much

of the U.S., an understanding of herbicide persistence as a function of soil type is









important in predicting the best time for revegetation. Samples of these soils were taken

after a certain amount of time after herbicide application and information on residue

amounts was generated using corn bioassay techniques. These residual data were used to

estimate the best time for revegetation to occur based on the imazapyr residues reaching a

tolerable level in soil.

In all three areas sprayed, detected residues were substantially lower than expected,

which could be due to a dense vegetative cover found in the areas during herbicide

application that might have prevented imazapyr from fully reaching the soil surface.

Vegetative cover, either as dead biomass or thatch, is common in areas chemically treated

for cogongrass. This might be beneficial in revegetation planning since soil imazapyr

residues might be lower than expected due to this foliar uptake. Six species can be

planted immediately after an imazapyr application of 0.84 kg ai/ha and expect to show no

less than 60% mortality 10 weeks after planting. These species (E. amplifolia, mimosa,

longleaf pine, E. grandis, silkgrass, and wiregrass) could potentially suppress cogongrass

regrowth if they are established at this critical time. Based on the wait time in relation to

injury data, E. grandis and switchgrass are good candidates for use in revegetation

planning. Several additional species, including E. amplifolia, mimosa, longleaf pine,

silkgrass, and wiregrass, would be good choices in a plantback scenario if percent

mortality is a more desirable quality than injury. These estimated plantback dates after

initial imazapyr application will be helpful in determining optimum timing of a

revegetation project. Knowing what species will best tolerate imazapyr and how long to

wait before planting can reduce the gap of time between initial cogongrass control and its

reinvasion of an area.









These data regarding the most tolerable plants to be used as revegetation species is

valuable research, but it is important to consider the costs involved with transplanting, as

well as the overall desirability of the species by landowners. Economical aspects should

be studied in future research and be taken into consideration to ultimately identify the

benefits of this type of revegetation planning.

As earlier stated, even in areas where management has been successful, cogongrass

re-infestation will often occur. Because of this, studying reinfestation of dormant

cogongrass rhizomes is also an important aspect of overall integrated control. In

addition, monitoring natural recruitment of native species in areas previously treated with

these herbicides will help to understand which plant species are more competitive with

cogongrass. Studies conducted show that cogongrass is continually suppressed over a

period of time after treatment with imazapyr. Glyphosate, also used on cogongrass,

provided consistently less control. This continued control of cogongrass in imazapyr

areas does not imply that imazapyr provides increased control as time progresses.

Instead, the data suggests that initial higher control of cogongrass with imazapyr

compared to glyphosate possibly allowed for other species to enter the area and compete

with the cogongrass as regrowth occurred.

Studying rhizome presence in areas previously treated for cogongrass control gave

data which help support the hypothesis that the continued growth and spread of

cogongrass after a treatment in 2000 is due to patches remaining from initial control

rather than regrowth from dormant rhizomes. This is because rhizomes were only found

where there were foliar patches. Overall, results of studies related to natural recruitment

in different soil types suggest that there are no significant long-term effects on native






79


plant recruitment due to imazapyr residues in the soil. After 2 years, there is no

significant difference in native species growth in two soil types for all levels of imazapyr.

These data are helpful in understanding how native species react to a post-imazapyr

treated area for further cogongrass suppression.

















APPENDIX
STANDARD CURVES FOR CORN ROOT BIOASSAY


imazapyr concentration (kg ai/ha)


Figure A-1. The effect of imazapyr concentration on corn root length in a sand tailings
soil type in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in sand tailings soil 0 Months After Treatment
(MAT). Values shown in Table 3.1.


\'




y=2.3+12.3*exp (-26.7*x)
\ R2= 0.87

\



4
*


+







81






18

16

14

12 -

10

8-
o
6 \ y=1.4+16.4*exp(-36.7*x)
\R2=0.97
4 \


2
0 I I I I----------------
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)






Figure A-2. The effect of imazapyr concentration on corn root length in a sand tailings
soil type in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in sand tailings soil 1 Month After Treatment
(MAT). Values shown in Table 3.1.







82






14


12


10 -


^ 8


I y=2.0+10.8*exp (-44.0*x)
-z 6 I
6 R2=0.97

4 \






0 I I I I I
0 -----------------------------------------------------
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)






Figure A-3. The effect of imazapyr concentration on corn root length in a sand tailings
soil type in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in sand tailings soil 3 Months After Treatment
(MAT). Values shown in Table 3.1.







83






18

16

14 -

12 -I

10


S8 y= 1.7+15.2*exp(-40.5*x)
SR2= 0.83
6- \

4 \

2 "

0 I I I I ------- --------
0.0 0.2 0.4 0.6 0.8 1.0 1.2

imazapyr concentration (kg ai/ha)





Figure A-4. The effect of imazapyr concentration on corn root length in a clay soil type
in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in clay soil 0 Months After Treatment (MAT).
Values shown in Table 3.2.
























I



y=1.4+16.4*exp(-36.7*x)
I
R2=0.97


\
\
I\


imazapyr concentration (kg ai/ha)






Figure A-5. The effect of imazapyr concentration on corn root length in a clay soil type
in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in clay soil 1 Month After Treatment (MAT). Values
shown in Table 3.2.





















12


10


8

y=1.5+12.1*exp(-23.3*x)
6 R2=0.90


4 \


2 4
~ -- -- -- -- -- -- -- ------- -- -- ---- --- -- ---- -- -


imazapyr concentration (kg ai/ha)







Figure A-6. The effect of imazapyr concentration on corn root length in a clay soil type
in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in clay soil 3 Months After Treatment (MAT).
Values shown in Table 3.2.




























y =2.0+12.6*exp(-28.3*x)
R2= 0.95




--------------------------------
\




*\ *


imazapyr concentration (kg ai/ha)






Figure A-7. The effect of imazapyr concentration on corn root length in an overburden
soil type in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in overburden soil 0 Months After Treatment (MAT).
Values shown in Table 3.3.


























y =1.6+11.8*exp(-33.0*x)
R2=0.94





* *-- - - - - - -


imazapyr concentration (kg ai/ha)






Figure A-8. The effect of imazapyr concentration on corn root length in an overburden
soil type in Polk County, FL. Regression analysis used to determine unknown
imazapyr concentrations in overburden soil 1 Month After Treatment (MAT).
Values shown in Table 3.3.