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Leguminous Cover Crop Fallows for the Suppression of Weeds


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LEGUMINOUS COVER CROP FALLOWS FOR THE SUPPRESSION OF WEEDS By AMANDA SHEA COLLINS 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 2004

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Copyright 2004 by Amanda Shea Collins

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I would like to dedicate this thesis to my parents Bru ce and Judy for their love and support while pursuing this endeavor, and my brothers, Mike and Nathan for always being there for me.

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ACKNOWLEDGMENTS First of all I would like to thank God for giving me the strength and patience to complete this journey. The time that I have spent in Gainesville have been some of the best and most challenging times of my life. The friends that I have made here will always hold a special place in my heart. I am extremely grateful to Dr. Carlene Chase for giving me the opportunity and financial support to pursue this degree. I thank her for all of her help and patience during my time here. I would like to thank my committee members, Dr. Bill Stall and Dr. Chad Hutchinson for their help and guidance throughout my project. I thank Dr. Greg MacDonald for being a great professor. I would like to show my appreciation to Jill Meldrum and Mike Alligood for all of their help in planting and harvesting of my experiments. It was great to work with the crews at Citra, Live Oak and Hastings. I am very appreciative for the help of Scott Taylor, Scott Kerr, Bart Herrington, John Morris, Bob Nielson, and Sam Willingham during my field experiments. Thank you also to Jana Col in the Statistics Department for help in analyzing data. iv

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TABLE OF CONTENTS page ACKNOWLEDGMENTS.................................................................................................iv LIST OF TABLES...........................................................................................................viii LIST OF FIGURES..........................................................................................................xii ABSTRACT.......................................................................................................................xv CHAPTER 1 INTRODUCTION AND LITERATURE REVIEW....................................................1 Reason for Phase Out....................................................................................................1 Chemical Alternatives for Methyl Bromide.................................................................3 1,3-dichloropropene + chloropicrin (Telone C-35 and C-17)......................................3 Chloropicrin..................................................................................................................4 Herbicides.....................................................................................................................5 Sustainable Agriculture................................................................................................6 Crop and Weed Interference.........................................................................................7 Cover Crops..................................................................................................................7 Allelopathy...................................................................................................................9 Cover Crop Species....................................................................................................10 Sunn HempCrotalaria juncea L......................................................................11 VelvetbeanMucuna deeringiana (Bort) Merr..................................................12 CowpeaVigna unguiculata L...........................................................................13 Weed Control..............................................................................................................14 Killing Cover Crops....................................................................................................14 Competition................................................................................................................15 Additive Experiments..........................................................................................16 Replacement Series Experiments........................................................................16 Objectives and Hypotheses.........................................................................................18 2 MATERIALS AND METHODS...............................................................................20 Replacement Series or Greenhouse Experiments.......................................................20 Preliminary Greenhouse ExperimentYellow Nutsedge...................................20 Greenhouse ExperimentsYellow Nutsedge.....................................................22 Greenhouse ExperimentsSmooth Amaranth...................................................22 v

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Preliminary Field Experiment.............................................................................22 Field Experiments 2003.......................................................................................25 Statistical Analysis......................................................................................................28 Greenhouse Data.................................................................................................28 Field Data............................................................................................................28 3 RESULTS AND DISCUSSION.................................................................................30 Replacement Series Experiments...............................................................................30 Yellow Nutsedge and Cowpea....................................................................................30 Plant Heights................................................................................................31 PAR..............................................................................................................31 Leaf Area and LAI.......................................................................................32 Tuber Production..........................................................................................34 Relative Yield...............................................................................................35 Yellow Nutsedge and Sunn Hemp..............................................................................36 Plant Heights................................................................................................36 PAR..............................................................................................................37 Leaf Area and LAI.......................................................................................37 Tuber Production..........................................................................................39 Relative Yield...............................................................................................40 Velvetbean....................................................................................................41 Plant Heights................................................................................................41 PAR..............................................................................................................42 Leaf Area and LAI.......................................................................................42 Tuber Production..........................................................................................43 Relative Yield...............................................................................................44 Smooth Amaranth and Cowpea..................................................................................45 Cowpea.........................................................................................................45 Plant Heights................................................................................................46 PAR..............................................................................................................47 Leaf Area and LAI.......................................................................................47 Relative Yield...............................................................................................49 Sunn Hemp...................................................................................................49 Plant Heights................................................................................................50 PAR..............................................................................................................51 Leaf Area and LAI.......................................................................................51 Relative Yield...............................................................................................53 Velvetbean....................................................................................................54 Plant Heights................................................................................................54 PAR..............................................................................................................54 Leaf Area and LAI.......................................................................................55 Relative Yield...............................................................................................57 4 RESULTS AND DISCUSSION.................................................................................59 Additive Experiments.................................................................................................59 vi

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Preliminary Experiment..............................................................................................59 Cowpea................................................................................................................59 Plant Regrowth....................................................................................................61 Sunn Hemp..........................................................................................................61 Plant Regrowth....................................................................................................63 Velvetbean...........................................................................................................63 Plant Regrowth....................................................................................................65 Additive Experiments 2003........................................................................................65 Cowpea.......................................................................................................................65 Plant Heights.......................................................................................................66 Crop Canopy........................................................................................................66 PAR.....................................................................................................................68 Plant Biomass......................................................................................................70 Plant Regrowth....................................................................................................71 Sunn Hemp.................................................................................................................72 Plant Heights.......................................................................................................72 Crop Canopy........................................................................................................73 PAR.....................................................................................................................75 Plant Biomass......................................................................................................76 Plant Regrowth....................................................................................................78 Velvetbean..................................................................................................................79 Plant Heights.......................................................................................................79 Plant Canopy.......................................................................................................82 PAR.....................................................................................................................84 Plant Biomass......................................................................................................86 Plant Regrowth....................................................................................................87 Comparison of Cover Crop Biomass at Common Densities...............................88 5 SUMMARY AND CONCLUSIONS.........................................................................93 APPENDIX A PRELIMINARY REPLACEMENT SERIES EXPERIMENT..................................97 B HASTINGS ADDITIVE EXPERIMENT................................................................102 LIST OF REFERENCES.................................................................................................110 BIOGRAPHICAL SKETCH...........................................................................................117 vii

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LIST OF TABLES Table page 3-1 Variables of main effects differences due to season Fall 2002 and Spring 2003.....30 3-2 Cowpea and yellow nutsedge heights in monoculture and mixture taken at 8 weeks after planting.................................................................................................31 3-3 PAR measurements taken at soil surface 8 weeks after planting in monoculture and mixture of cowpea and yellow nutsedge...........................................................32 3-4 Leaf area index of cowpea and yellow nutsedge in monoculture and mixture 8 weeks after planting.................................................................................................33 3-5 Leaf area per plant of cowpea and yellow nutsedge................................................33 3-6 Total leaf area of cowpea and yellow nutsedge.......................................................33 3-7 Combined leaf area: cowpea and yellow nutsedge Fall 2002 and Spring 2003.......34 3-8 Tuber production 8 weeks after planting for all proportions of cowpea: weed.......35 3-9 Mean values of sunn hemp for all variables by experiment fall 2002 and spring 2003..........................................................................................................................36 3-10 Sunn hemp and yellow nutsedge heights taken at 8 weeks after planting...............37 3-11 PAR measurements at soil surface taken and middle of sunn hemp canopy 8 weeks after planting.................................................................................................37 3-12 Leaf area index of sunn hemp and yellow nutsedge................................................38 3-13 Leaf area per plant of sunn hemp and yellow nutsedge...........................................38 3-14 Total leaf area of sunn hemp, yellow nutsedge........................................................39 3-15 Combined leaf area sunn hemp and yellow nutsedge..............................................39 3-16 Tuber production 8 weeks after planting for all proportions of nutsedge................40 3-17 Mean values of velvetbean for all variables by season fall 2002 and spring 2003..41 viii

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3-18 Velvetbean and yellow nutsedge heights taken at 8 weeks after planting...............42 3-19 PAR at soil surface taken at 8 weeks after planting.................................................42 3-20 Leaf area index per area of box of velvetbean and yellow nutsedge.......................43 3-21 Leaf area per plant of velvetbean and yellow nutsedge...........................................43 3-22 Total leaf area of velvetbean and yellow nutsedge..................................................43 3-23 Tuber production 8 weeks after planting for all proportions of nutsedge................44 3-24 Mean values of cowpea for all variables by season: spring and summer 2003........46 3-25 Cowpea and smooth amaranth heights taken 8 weeks after planting.......................46 3-26 PAR taken 8 weeks after planting of cowpea and smooth amaranth.......................47 3-27 Leaf area index per area of box of cowpea and smooth amaranth...........................47 3-28 Leaf area per plant of cowpea and smooth amaranth...............................................48 3-29 Total leaf area and combined leaf area of cowpea and smooth amaranth................48 3-30 Mean values of sunn hemp for all variables by season: spring and summer 2003..50 3-31 Sunn hemp and smooth amaranth heights taken 8 weeks after planting..................50 3-32 PAR measurements at soil surface and middle of sunn hemp canopy 8 weeks after planting............................................................................................................51 3-33 Leaf area index per area of box for sunn hemp and smooth amaranth....................51 3-34 Leaf area per plant of sunn hemp and smooth amaranth..........................................52 3-35 Total leaf area of sunn hemp and smooth amaranth.................................................52 3-36 Combined leaf area of sunn hemp and smooth amaranth........................................53 3-37 Mean values of velvetbean for all variables by season: spring and summer 2003..54 3-38 Velvetbean and smooth amaranth heights taken 8 weeks after planting..................54 3-39 PAR readings taken at soil surface 8 weeks after planting......................................55 3-40 Leaf area index per area of box of velvetbean and smooth amaranth......................56 3-41 Leaf area per plant of velvetbean and smooth amaranth..........................................56 3-42 Total leaf area of velvetbean and smooth amaranth.................................................56 ix

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3-43 Combined leaf area of sunn hemp and smooth amaranth........................................57 4-1 Crop dry weights separated by location z ..................................................................71 4-2 Smooth amaranth biomass by density......................................................................71 4-3 Cowpea regrowth 2 and 4 weeks after termination and weed biomass 4 weeks after termination.......................................................................................................72 4-4 Sunn hemp regrowth 4 weeks after termination of experiment. z ............................78 4-5 Weed biomass at 2 and 4 weeks after termination of sunn hemp............................79 4-6 Velvetbean dry biomass 6 and 12 weeks after planting. z ........................................86 4-7 Weed biomass at Citra and Live Oak in response to the density and location........88 4-8 Cover crop biomass at Citra at the 2 common densities (20 and 40 plants/m). z .....89 4-9 Crop biomass at Live Oak at the 2 common densities (20 and 40 plants/m). z ........90 A-1 Cowpea and yellow nutsedge heights taken 8 WAP................................................97 A-2 Cowpea and yellow nutsedge LAI based on area of box.........................................98 A-3 Leaf area and combined leaf area of cowpea and yellow nutsedge.........................98 A-4 Tuber dry weight and tuber production of yellow nutsedge....................................98 A-5 PAR penetrating to the canopy of cowpea and yellow nutsedge.............................99 A-6 Sunn hemp and yellow nutsedge heights 8 WAP..................................................100 A-7 LAI of sunn hemp and yellow nutsedge based on area of box...............................100 A-8 Leaf area of sunn hemp and yellow nutsedge........................................................100 A-9 Combined leaf area of sunn hemp and yellow nutsedge........................................100 A-10 Tuber dry weight and production...........................................................................101 A-11 PAR measured in middle and below the canopy....................................................101 B-1 Cowpea mean heights at weeks 3 and 12 and weed height means at week 3........103 B-2 Regrowth of cowpea and weed population 2 and 4 weeks after cover crop kill....105 B-3 Sunn hemp mean heights at weeks 3 and 12 and weed height means at week 3...105 B-4 Regrowth of weed population 2 and 4 weeks after cover crop kill........................107 x

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B-5 Velvetbean mean heights at weeks 3 and 12 and weed height means at week 3...107 B-6 Velvetbean and weed regrowth 2 and 4 weeks after cover crop kill......................109 xi

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LIST OF FIGURES Figure page 2-1 Greenhouse replacement series planting pattern for all experiments.......................21 2-2 Planting pattern for cover crop densities: 2002 and 2003........................................24 2-3 Smooth amaranth planting pattern for additive experiments summer 2002............25 2-4 Planting pattern of smooth amaranth in additive experiments, summer 2003.........27 3-1 Relative yields of cowpea (RYCP) and yellow nutsedge (RYNS) and relative yield total (RYT) eight weeks after planting............................................................35 3-2 Relative yields of Sunn hemp (RYSH) and yellow nutsedge (RYNS) and relative yield total (RYT) eight weeks after planting...............................................40 3-3 Relative yields of velvetbean (RYVB) and yellow nutsedge (RYNS) and relative yield total (RYT) eight weeks after planting...............................................44 3-4 Relative yields of cowpea (RYCP) and smooth amaranth (RYSA) and relative yield total (RYT) eight weeks after planting............................................................49 3-5 Relative yields of sunn hemp (RYSH) and smooth amaranth (RYSA) and relative yield total (RYT) eight weeks after planting...............................................53 3-6 Relative yields of velvetbean (RYVB) and smooth amaranth (RYSA) and relative yield total (RYT) eight weeks after planting...............................................58 4-1 Cowpea heights at 10 weeks after planting (WAP).................................................60 4-2 PAR within the cowpea canopy 30.5 cm above the soil surface 10 WAP...............60 4-3 Biomass of cowpea and smooth amaranth at 10 WAP............................................61 4-4 Sunn hemp heights at 10 WAP................................................................................62 4-5 PAR within the sunn hemp canopy at 30.5 cm above soil surface 10 WAP...........62 4-6 Biomass of sunn hemp and smooth amaranth 10 WAP...........................................63 4-7 Velvetbean heights at 10 WAP................................................................................64 xii

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4-8 PAR within the velvetbean canopy at 30.5cm above soil surface 10 WAP.............64 4-9 Biomass of velvetbean and smooth amaranth 10 WAP...........................................65 4-10 Cowpea height as affected by time and smooth amaranth height as affected by time and location......................................................................................................66 4-11 Crop canopy of cowpea as affected by location and density at 10 and 30 plants/ m.............................................................................................................67 4-12 Smooth amaranth canopy as affected by location and week....................................68 4-13 PAR penetrating cowpea canopy at Citra as affected by density and time..............69 4-14 PAR penetrating the cowpea canopy at Live Oak as affected by density and time...........................................................................................................................69 4-15 Cowpea biomass response to density and week.......................................................70 4-16 Effects of crop density and location on sunn hemp and smooth amaranth heights......................................................................................................................73 4-17 Effect of time and location on sunn hemp and smooth amaranth heights................73 4-18 Effect of time on sunn hemp canopy size................................................................74 4-19 Smooth amaranth canopy size in response to location and week.............................74 4-20 PAR penetrating the sunn hemp canopy at Citra as affected by density and week.........................................................................................................................75 4-21 PAR penetrating the canopy of sunn hemp at Live oak as affected by density and week...................................................................................................................76 4-22 Effect of crop density on biomass of sunn hemp taken six and 12 weeks after planting at Citra........................................................................................................77 4-23 Effect of density on sunn hemp six and 12 weeks after planting at Live Oak.........77 4-24 Effect of density of sunn hemp on biomass of smooth amaranth............................78 4-25 Velvetbean and smooth amaranth heights as affected by week and location..........80 4-26 Velvetbean heights in response to week and density...............................................81 4-27 Effect of velvetbean density and time on smooth amaranth heights........................81 4-28 Effect of velvetbean density and location smooth amaranth heights.......................82 xiii

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4-29 Velvetbean canopy size in response to location and time........................................83 4-30 Effect of time and density on velvetbean canopy size.............................................83 4-31 Effect of time and location on smooth amaranth canopy size..................................84 4-32 Effect of crop density and time on PAR beneath the velvetbean canopy................85 4-33 PAR penetrating the canopy as affected by density and location............................85 4-34 Effect of time and location on PAR measured at the base of the canopy................86 4-35 Effect of density on biomass 6 and 12 weeks after planting....................................87 4-36 Effect of density on smooth amaranth biomass at Citra and Live Oak....................87 B-1 Cowpea PAR taken at 3 and 12 weeks after planting............................................103 B-2 Biomass of cowpea and weed population at time of harvest.................................104 B-3 Sunn hemp PAR taken at 3 and 12 weeks after planting.......................................106 B-4 Biomass of sunn hemp and weed population at time of harvest............................106 B-5 Velvetbean PAR taken at 3 and 12 weeks after planting.......................................108 B-6 Effect of density on biomass of velvetbean and weeds at time of harvest.............109 xiv

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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 LEGUMINOUS COVER CROP FALLOWS FOR THE SUPPRESSION OF WEEDS By Amanda Shea Collins August 2004 Chair: Carlene A. Chase Major Department: Horticultural Sciences Cover crops are becoming an important component in both sustainable agriculture and organic vegetable production. The use of cover crops during summer fallow periods has many advantages including weed and nematode suppression, protection from soil erosion, and the contribution of soil organic matter. The leguminous cover crops used in this study give the added benefit of enhancing soil nitrogen and have been shown to be nematode suppressive. Greenhouse replacement series experiments were performed in Gainesville, FL, in 2002 and 2003 to evaluate the competitiveness of the cover crops cowpea (Vigna unguiculata cv Iron and Clay), sunn hemp (Crotalaria juncea), and velvetbean (Mucuna deeringiana) when grown in combination with two model weed species, yellow nutsedge (Cyperus esculentus) and smooth amaranth (Amaranthus hybridus). With yellow nutsedge the effect of the cover crops on tuber production was also evaluated. Cowpea and sunn hemp were found to be slightly less competitive and velvetbean was slightly more competitive than yellow nutsedge. Increasing the proportion of the cover crops in the crop:weed mixture from 25:75 to 75:25 did not xv

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significantly affect tuber number or tuber weight per nutsedge plant. Cowpea was slightly more competitive than smooth amaranth and both sunn hemp and velvetbean were much less competitive than smooth amaranth. Additive field experiments were performed to determine the optimum cover crop populations for suppression of smooth amaranth. In a preliminary experiment at the North Florida Research and Education Center (NFREC) in Live Oak, FL, in 2002 a range of cover crop densities was evaluated in mixtures with smooth amaranth at a constant density of 5 plants/m. After 10 weeks on a dry biomass basis, smooth amaranth was suppressed by cowpea, sunn hemp, and velvetbean at the lowest populations (38, 44, and 15 plants/m 2 respectively), with no further decrease in biomass as cover crop population increased. Based on these results, in 2003 at the Plant Science Research and Education Unit (PSREU) in Citra and NFREC in Live Oak, cover crop densities were lowered and smooth amaranth population was increased to 15 plants/m. Cowpea density had no effect on smooth amaranth biomass in these experiments. However, smooth amaranth biomass declined linearly as sunn hemp density increased so that smooth amaranth biomass was 51% lower with 100 sunn hemp plants/m 2 than in the absence of sunn hemp. Similarly with increasing density of velvetbean, biomass and a linear decrease in smooth amaranth biomass at PSREU; however, at NFREC there was a quadratic decrease in smooth amaranth biomass with maximum suppression occurring at the highest density of 50 plants/m. Although these cover crop species were not consistently more competitive in the greenhouse experiments, planting densities can be manipulated to obtain adequate smooth amaranth suppression in the field. Higher cover crop densities will be needed with larger weed infestations. xvi

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CHAPTER 1 INTRODUCTION AND LITERATURE REVIEW There is an impending ban on methyl bromide use in the U.S. Therefore, it is important that alternatives are found to suppress both weed and nematode populations. There is a need for both chemical and non-chemical alternatives. The use of cover crops during summer fallow can be a viable alternative for both conventional and organic growers. Methyl bromide is one of the most popular broad spectrum soil fumigants currently used by farmers and is an important fumigant utilized in world vegetable production. It is used to suppress soil-borne diseases, nematodes, insects and weeds in more than 100 crops, ornamental nurseries, forestry, and wood products (Schneider et al., 2003). Methyl bromide is currently being phased out and the most recent phase out date of January 2005 has been extended. The vegetable industry will be severely impacted as a result of this phase out, unless, suitable alternatives to this fumigant are identified. The Montreal Protocol acknowledged that there were no suitable alternatives for many applications, therefore the phase out has been extended (Initiatives, 2004). These decisions indicate that methyl bromide will be available beyond 2005 until viable alternatives are available. Research is currently being performed on both chemical and non-chemical alternatives. Reason for Phase Out Methyl bromide was dessignated by the Montreal Protocol of 1991 to be an ozone-depleting chemical. In accordance with this definition, methyl bromide manufacturing and importation in developed countries was scheduled for phase out as follows: 1

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2 25% reduction in 1999 50% reduction in 2001 70% reduction in 2003 100% reduction in 2005 Exemptions for developed and developing countries include certain pre-shipment uses, critical use and quarantine uses (Schneider et al., 2003). Consumption for developing countries varies from that of developed countries. Developing countries had a freeze imposed in 2002 at 1995-1998 average levels, a 20% reduction in 2005 and phase out completion in 2015 (Schneider et al., 2003). Developed and developing countries can file for exemptions, including critical uses, quarantine and certain preshipment uses (Schneider et al., 2003). Methyl bromide has been identified as critical for the production and marketing of many fruit and vegetable crops (VanSickle et al., 2000; Webster et al., 2001). The fumigant has been utilized since the 1950s in minor-use crops to eliminate pest problems (Webster et al., 2001). There are a limited number of alternative pesticides registered in minor use crops because of the high cost of registering new pesticides (Webster et al., 2001). Methyl bromide is applied as soil fumigant and is immediately covered by plastic mulch. Soil fumigation accounts for nearly 80% of the worldwide use of methyl bromide (United Nations Environmental Programme, 1997). Tomatoes (35%) and strawberries (20%) account for more than half of the methyl bromide used in the U.S. (VanSickle et al., 2000). It is estimated that the loss of methyl bromide will have a $1 billion impact on the U.S. winter vegetable industry, and Florida will account for the majority of this impact (Spreen et al., 1995; VanSickle et al., 2000). Due to the phase out of methyl

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3 bromide, the concentration applied in methyl bromide: chloropicrin mixtures has been lowered from a 98:2 to 67:33. More than three-fourths of Florida growers cite the loss of methyl bromide as their biggest concern for future pest management. Chemical Alternatives for Methyl Bromide Several chemicals are currently being tested for replacement of methyl bromide. These include fumigants and herbicides such as 1,3-dichloropropene (1,3-D) chloropicrin and napropamide. These have been studied in varying combinations and rates. No single chemical by itself has proven to be a suitable alternative to this point. Gilreath et al. (2004) indicate that there are several alternatives for methyl bromide in vegetable crops. However, effectiveness of available alternatives can be affected by the nature of the crop rotation and the planting season (Gilreath et al., 2004). There is no single molecule that could replace methyl bromide due to inconsistency of fumigant efficacy (Gilreath et al., 2004). 1,3-dichloropropene + chloropicrin (Telone C-35 and C-17) There are many restrictions on the use of 1,3-dichloropropene in Florida and additional use restrictions in certain Florida counties (Dow Agrosciences, 2003 a,b). 1,3-D can only be applied in areas with a shallow hard pan or soil layer restrictive to downward water movement (such as spodic horizon) within six feet of the ground surface and that are capable of supporting seepage irrigation regardless of irrigation method employed (Dow Agrosciences, 2003 b). These counties include: Collier, Dade, Hillsborough, Indian River, Lake, Okeechobee, Palm Beach and Polk (Dow Agrosciences, 2003 a,b). Field selection is important when using 1,3-D because it cannot be applied within 100 feet of drinking water wells or occupied structures (Dow Agrosciences, 2003 b). Personal protective equipment required during 1,3-D application

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4 includes a full spray suit, rubber gloves, boots and full-face respirator for all personnel present in the field during the in-row application. Due to these requirements, which are uncomfortable under hot Florida conditions, research is being shifted toward a broadcast application of Telone mixtures. Research has been conducted in strawberries using a combination of Telone C-17 or C-35 + Devrinol as an in-row treatment. This combination was compared to methyl bromide for weed, strawberry yield response disease and nematode control (Noling and Gilreath, 2002). With some variability, the response of the strawberry plants in both yield and growth to Telone C-17 or C-35 + napropamide were nearly equivalent to that of methyl bromide (Noling and Gilreath, 2002). However, due to the additional costs previously mentioned, additional methods of application still need to be identified for this to be a good alternative to methyl bromide. Chloropicrin Chloropicrin was first tested as a preplant soil fumigant in 1920 (Wilhelm, 1996). Chloropicrin is very effective against soil-borne disease, some nematodes, and other pests (Wilhelm, 1996). Therefore, to improve its spectrum of control it is combined with compounds such as 1,3-dichloropropene for nematode control and compounds such metam sodium, dazomet and pebulate for their herbicidal properties (Wilhelm, 1996). However, pebulate is no longer available. Chloropicrin is a soil fumigant that is injected into the soil approximately 15.225.4 cm below the surface at least 14 days prior to planting (Wilhelm, 1996). Chloropicrin is a tear-producing chemical, and protection must be taken during application to avoid harmful exposure. Chloropicrin undergoes rapid breakdown in sunlight and does not have significant ozone depleting potential. It is metabolized in the soil to carbon dioxide (Wilhelm, 1996).

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5 Herbicides Few herbicides are registered for vegetable production making weed control extremely difficult (Creamer and Baldwin, 2000). Pesticide registration is very expensive, and vegetable crops are planted on a relatively small number of hectares, further inhibiting registration for these minor use crops (Webster et al., 2001). Although registered fumigants are available for use as methyl bromide alternatives there are limited numbers of effective herbicide partners registered for use in vegetable crops (Schneider et al., 2003). One alternative is napropamide (Devrinol), an amide herbicide compound that is applied to the soil and must be incorporated within seven days of the application or sprinkler irrigation. Napropamide can be applied up to 35 days prior to harvest or preemergence in a tank mix in crops such as strawberries, tomatoes, and peppers (United Phosphorus Inc. 2002). This is often applied with Telone to increase weed control. It also has a residual period of 4-10 months. This combination can be used in both strawberries and tomatoes, two of the most valuable crops grown in Florida. Tillam, a preemergence herbicide that must be incorporated into the soil immediately has shown promise as a partner to fumigants due to its ability to effectively control both yellow and purple nutsedge later in the growing season (Gilreath et al., 1996). However, the registration under Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) lapsed in December 2002 and is no longer available (Osteen, 2003). Halosulfuron methyl (Sandea) has shown promise as a preplant or postemergent herbicide for within row and row middles for control of nutsedges, pigweeds and ragweed in asparagus, cucumbers, cantoloupes and fruiting vegetables (Gowan Company, 2002).

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6 Sustainable Agriculture In addition to chemical alternatives, more sustainable nonchemical alternatives to methyl bromide are also being investigated. Sustainable agriculture is profitable crop production that builds soil resources and prevents environmental contamination. Sustainability also involves social, economic, and ecological relationships at local, national, and global levels (Abdul-Baki and Teasdale, 1997). The goal of sustainable agriculture is to conserve, build and maintain the soil at a high level of fertility (Abdul-Baki and Teasdale, 1997). There is an increasing concern among producers, agricultural scientists and the general public about reducing the environmental impacts of agriculture, and a growing interest in maintaining or improving the quality of agricultural soils (Doran et al., 1994). This has caused a shift towards practicing sustainable agriculture. Some of the reasons for this are: contamination of the environment by agricultural chemicals, soil erosion, depletion of natural resources and pesticide residues in food (Lu et al., 2000). Some of the major practices being used in sustainable agriculture include crop rotations, reduced tillage, use of animal manures, and cover crops (Lu et al., 2000). The Weed Science Society of America supports the concept that sustainable agriculture must include the profitable production of an abundant quantity of high quality, reasonably priced food and other agricultural products while maintaining or improving natural resources and having minimal adverse impact on the environment (Creamer et al., 1996; Worsham, 1991). Since weeds are a major factor affecting efficient agricultural production, employment of efficient, economical, and environmentally safe weed management systems will be necessary to maintain a viable sustainable agriculture (Creamer et al., 1996; Worsham, 1991). The absence of a suitable

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7 chemical alternative to methyl bromide underscores the need for more sustainable approaches to pest management in vegetable crops. Crop and Weed Interference Weed interference is the direct effects that weeds might impose upon other plants, such as competition, allelopathy, parasitism, and indirect effects not referring to any one particular effect. Crop interference may be described as crop effects on weeds that reduce weed emergence, biomass, and yield. In many cropping systems, crop interference with weed growth and reproduction is a fundamental method of weed control (Jordan, 1993). The interest in weed control through crop interference has been revived due to the need to reduce environmental and economic costs of crop production. Crop interference should occur as early as possible in growth to prevent resource consumption by weeds (Jordan, 1993). Crops interfere with weed growth and vice versa (Jordan, 1993). Crop interference can be an important component of integrated weed management systems. Cover Crops Cover crops are becoming an important component of sustainable agriculture. Cover crops have the potential to be an alternative weed control method for both conventional and organic farmers. Organic farmers do not use synthetic herbicides or fertilizers for crop production and utilize alternative means to manage weeds and fertilize crops. Using leguminous cover crops as green manure can replenish the soil of essential nitrogen (N) at the end of the growing season. The principal goal of using cover crops for weed control is to replace an unmanageable weed population with a manageable cover crop (Teasdale, 1996).

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8 This is accomplished by adjusting the phenology of the cover crop to preempt the niche occupied by weed populations (Teasdale, 1996). Cover crops play an important part in sustainable agriculture by preserving productivity of soil resources and maintaining environmental quality. While cover crops are not usually planted for profit or economic value, they can have environmental value directly with respect to maintaining improved soil quality and indirectly through reduction in pesticide use. However, the success of cover crops depends on a balance of positive and negative cover crop influences (Teasdale, 1996). One of the most important factors affecting the cover crops profitability is their ability to enhance crop yields (Lu et al., 2000). Studies on fresh market tomato production have shown that tomatoes grown with hairy vetch mulch were higher yielding and more profitable than those grown with no mulch or black polyethylene mulch (Lu et al., 2000). According to Teasdale (1996) and Lu et al. (2000) some of the common advantages of growing cover crops are nutrient enhancement (particularly when using a legume cover crop prior to a grain crop), soil nutrient capture, soil moisture retention, long-term soil stabilization, improve soil organic content, control pests, reduce weed competition, reduce the need for herbicides, provide suitable habitat for beneficial predator insects, and act as non-host crops for nematodes and other pests in crop rotations. Through the use of cover crops and crop management systems weed populations and crop yield can be affected by cover crops and management systems in both the long and short term (Ngouajio et al., 2003). Growing cover crops also has disadvantages including additional management and expense, interference with crop establishment, soil moisture depletion, cooler soil

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9 temperatures, and less predictable crop fertilizer requirements (Teasdale, 1996). A major concern of using cover crops in cooler climates is that soil will be cooled to a point in which crop production is delayed (Abdul-Baki et al., 1996; Hutchinson and McGiffen, 2000; Masiunas et al., 1995). Therefore, the use of cover crops can be a disadvantage when the soil must be warmed quickly after a cold winter (Hutchinson and McGiffen, 2000; Knavel and Herron, 1986; Masiunas et al., 1995). Another consequence of growing cover crops is that they use soil water causing a positive, neutral, or negative effect on the soil water supply for the next crop. Negative effects may occur when cover crops use excess water in areas with limited amounts of rainfall. In general, cover crops deplete water when growing and conserve water when they are killed, if the residue remains on the soil (Unger and Vigil, 1998). Allelopathy Cover crops are also grown for their allelopathic properties. Allelopathy refers to any direct or indirect harmful effect produced in one plant through toxic chemicals released into the environment (Rice, 1974). This definition has been broadened to include chemicals produced by actinomycetes, algae, fungi, or other microbes that may associate with the plants in the rhizosphere (Weston, 1996). Many cover crops release significant levels of allelochemicals that reduce weed emergence (Barnes and Putnam, 1983, Masiunas et al., 1995, Putnam et al., 1983). Allelopathy is often inferred from the response of a target plant to the presence of extracts, leachates, or ground plant tissue. The effectiveness of allelopathy depends on a chemical compound being added to the environment, whereas competition is the removal or reduction of some factor from the environment required by other plants or microorganisms sharing the habitiat (Birkett et al., 2001). Chemicals with allelopathic potential are present in virtually all plants and in

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10 most tissues, including leaves, stems, flowers, roots, seeds, and buds (Caamal-Maldonado et al., 2001). Under appropriate conditions, these chemicals may be released into the environment in sufficient quantities to affect neighboring plants (Caamal-Maldonado et al., 2001). Scientists agree that allelopathy is a component of plant interference, but they do not agree on the relative importance of its contribution to plant growth and community structure (Hoffman et al., 1996). One common way that allelopathy may be utilized in weed management systems is through the manipulation of allelopathic cover crop residues in annual and perennial cropping systems (Caamal-Maldonado et al., 2001). The effects of microbial enhancement on cover crop decomposition or release of allelochemicals is unknown, but may contribute to a rapid release of water-soluble inhibitors (Caamal-Maldonado et al., 2001). Annual legume residue has also been shown to release allelochemicals that suppress germination and growth of selected species (Caamal-Maldonado et al., 2001). However, little is known about the influence of legume cover crops on weed populations in the field (Teasdale et al., 1991). Cover Crop Species Sunn hemp (Crotalaria juncea L.), velvetbean (Mucunadeeringiana (Bort) Merr) and cowpea (Vigna unguiculata L.) are three leguminous summer cover crops that have the potential for inclusion in vegetable production rotations (Creamer and Baldwin, 2000). Further evaluation is needed to use these three cover crops as candidates as biological alternatives for methyl bromide in south Florida (Wang et al., 2003).

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11 Sunn HempCrotalaria juncea L. Sunn hemp is a tropical legume that may be adapted to residue management systems. It has already been used extensively for soil improvement or green manuring in the tropics (Lales and Mabbayad, 1983). Sunn hemp is non-toxic and can be used as forage as well as green manure. Although sunn hemp is not winter hardy, it may be able to produce sufficient biomass during the fall (until frost) to provide groundcover and N to a following summer cash crop in southern temperate regions (Zulfadi et al., 1997). Sunn hemp is a superior cover crop with good germination rates and produces a thick ground cover rapidly (Li et al., 2000; Li et al., 1999). In south Florida, sunn hemp can grow 183-356 cm tall in a period of 12 weeks (Li et al., 2000). Other cover crops are not known to grow as quickly (Li et al., 2000). In addition to excellent biomass yields, subsequent cash crop yields with a prior sunn hemp cover crop have been promising. Li et al. (1999) concluded that sunn hemp is better than currently used cover crops in south Florida. Work done by Mansoer et al. (1997) showed that sunn hemp produced large quantities of dry matter during the fall season and covered the soil surface rapidly, protecting it from erosion. Li et al. (1999) found that sunn hemp fixed and retained up to 248 lb N/ac. Sunn hemp is of interest as a cover crop because it is also suppresses plant parasitic nematodes (McSorley, 1998, 1999; McSorley and Dickson, 1989, 1995; Wang et al., 2002), which makes it a useful addition to a nematode susceptible crop rotation (Li et al., 2000). Tomatoes produced significantly higher early yield and total extra large fruit and total marketable yield when grown in sunn hemp plots compared to those grown in sesbania treatments and the control (Li et al., 1999). The high biomass and nitrogen fixation by sunn hemp may be the major factor of the higher yields (Li et al., 1999).

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12 VelvetbeanMucuna deeringiana (Bort) Merr Velvetbean grows fast and produces abundant biomass. Research done by Caamal-Maldonado et al. (2001) suggested that velvetbean was very effective for weed suppression. Their research also evaluated phytotoxic effects and they found that velvetbean affected the growth of weeds more than the germination. Caamal-Maldonado et al. (2001) found that velvetbean would be useful in tomato crops because the phytotoxic effects only affect the weed population and cause no damage to transplanted tomato plants, although direct seeded tomato plants were affected. Many plants possess phytotoxic properties; however, the actual chemical has not been isolated and this allelopathy remains unproven. The main allelopathic agent of velvetbean is known to be L-3,4-dihydrophenylalanine (L-DOPA). Various unusual aminoacids have also been found in velvetbean as well as other leguminous cover crop species (Caamal-Maldonado et al., 2001; Fujii, 1999). Velvetbean also suppresses plant parasitic nematodes (McSorley, 1998, 1999; McSorley and Dickson, 1989, 1995, Wang et al., 2002). Research done by Brunson et al. (1994) indicated that plots planted with velvetbean after final harvest and disked in 90 days later had substantially lower numbers of nematodes whereas most conventional plots showed an increase. Wang et al. (2003) found that the nematode suppressive effects of velvetbean persisted long enough to avoid significant yield loss when planted in rotation with highly nematode-susceptible soybean. Velvetbean is also an important contributor of organic matter to the soil. Velvetbean is very effective in fixing and recycling N, preventing significant nutrient losses to the environment practically eliminating the need for external fertilizer without compromising yield (Buckles et al., 1998; Capo-chichi et al., 2002). Velvetbean

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13 competes well with weeds because of its rapid and extensive growth. Caamal-Maldonado et al. (2001) showed that velvetbean was the most effective of four legume species (jackbean, jumbie bean, wild tamarind) at suppressing weeds. The canopy of velvetbean when completely developed significantly decreases the amount of light that reaches the soil. Wang et al. (2002) found no significant difference in tomato plots planted with velvetbean compared with plots that were fallow or planted with sunn hemp or sorghum sudangrass. However, the biomass of tomatoes grown in velvetbean plants were significantly less than with the other cover crop treatments. CowpeaVigna unguiculata L. Cowpea is a warm season plant that is well adapted to heat and drought conditions. According to research performed by Creamer and Baldwin (2000) cowpea was shown to be very vigorously competitive with weeds, and produced large amounts of biomass and N. Mulch from a prior cowpea cover crop has been shown to reduce the weed populations significantly in pepper at three, five, and nine weeks after transplanting. (Hutchinson and McGiffen, 2000). Ngouajio et al. (2003) found that using cowpea as a mulch in lettuce production resulted in a smaller weed infestation than sudangrass cover crop that was incorporated prior to planting the lettuce. Cowpea also produced the highest lettuce yield when incorporated into the soil prior to transplanting partially due to the amount of N fixed by the cowpea (Ngouajio et al., 2003). However, an increase in populations of perennial weeds such as bermudagrass and yellow nutsedge occurred in the cowpea plots over time and could cause serious constraints if their populations build over several seasons. Wang et al. (2002) found that tomato yields with a prior cowpea cover crop were lower than those of the fallow plots; however, tomato biomass was

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14 greater than with the other cover crop treatments. They believe that this could be due to chemical characteristics in the cowpea residues or the Carbon/Nitrogen ratio. Like sunn hemp and velvetbean, some cowpea cultivars have been shown to suppress plant parasitic nematodes (McSorley, 1998, 1999; McSorley and Dickson, 1989 1995; Wang et al., 2002). Weed Control Weed control is essential for maximum crop yields and high quality produce. Weed control can be serious limitation to vegetable production and is the principal reason for farmers not converting to organic agriculture (Davies et al., 1997; Walz, 2002). Weed control and crop yield were improved and more consistent when cover crops were supplemented with herbicides in various reduced tillage systems (Teasdale, 1996). Reducing the use of preemergence herbicides could reduce environmental impact since these are more frequently detected in ground and surface waters than postemergence herbicides (National Research Council, 1989, Teasdale, 1996). Postemergence herbicides are generally used at lower rates, are less persistent and could eventually replace preemergence herbicides (Teasdale, 1996). Some weed management practices that are being emphasized are cultural practices, use of herbicides at minimal rates to control specific weeds, mechanical cultivation, and field scouting techniques to determine the need and choice of herbicides, to maintain a profitable yield while protecting the environment and natural resources for future generations (Creamer et al., 1996). Killing Cover Crops In the southeast, it appears that the most practical method for killing cover crops is to use a nonselective herbicide followed by a selective postemergence herbicide as needed, especially for grasses and weeds (Worsham, 1991). Using this approach will

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15 enhance the sustainability of agriculture for the following reasons: a) conservation of soil, b) the use of herbicides (especially preemergence herbicides) should be reduced, c) herbicides used for killing cover crops have little to no potential for contaminating groundwater, and d) postemergence selective herbicides have little potential for environmental contamination (Worsham, 1991). An alternative method is to mechanically kill the cover crops. Mechanical methods include mowing, rolling, roll-chopping, undercutting and partially rototilling (Creamer and Dabney, 2002). The success of these types of management strategies depend partially on the growth stage and species of the cover crops (Creamer and Dabney, 2002). The method of killing cover crops can affect weed emergence. Crop residue left intact on the soil surface by undercutting or sickle bar mowing of the cover crops yielded fewer weeds than the finely chopped residue that results with a flail mower (Creamer and Dabney, 2002, Creamer et al., 1995). Creamer and Dabney, (2002) found that mowing in the vegetative state was more effective method at killing cowpea than undercutting and rolling. These methods killed 98%, 85%, 5 %, respectively. These methods were even more effective on velvetbean resulting in 100%, 95%, 52% of the velvetbean killed with mowing, undercutting, and rolling, respectively (Creamer and Dabney, 2002). Competition Competition results from a loss in crop yield or quality from interactions among crops and weeds (Radosevich, 1987). Competition continues to be the most widely debated issues in ecology. There are several methods to study competition including: replacement series experiments or substitutive experiments, additive experiments, systemic methods, addition series experiments and neighborhood experiments

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16 (Radosevich, 1987). The replacement series and additive approach were used to study competition between cover crops and yellow nutsedge and smooth amaranth. Additive Experiments Additive experiments are commonly used by weed scientists and are more adaptable to field conditions than greenhouse conditions. Additive studies can be performed using two or more plant species, however they are usually performed using only two species a crop and a weed (Radosevich, 1987). In this design, the density of one species is held constant while the density of another species is varied (Cousens, 1991, Radosevich, 1987). In general, the crop density is held constant and the weed density is varied. However, in the present study, experiments were performed with the weed population at a constant density and varying the crop density. The additive approach has been criticized for not adequately taking into account the influence of total density and species proportion on the outcome of competition (Harper, 1977; Radosevich et al., 1997). In addition, the total plant density varies among treatments and, therefore the proportion among species changes simultaneously with total plant proportion (Radosevich et al., 1997). Because both density and proportion vary, it is difficult to interpret the effects of either factor alone (Radosevich et al., 1997). The additive approach is appropriate for this study because it allows the examination of a range of cover crop densities to determine an optimum density for weed suppression. Replacement Series Experiments The substitutive approach is more commonly used by ecologists and is often used in greenhouse experiments. The replacement series measures competition between two plant species by varying proportions of each species while maintaining a constant total density. Monocultures of each species are also included in replacement series

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17 experiments (Cousens, 1991; Jollife, 2000; Radosevich, 1987). Replacement series experiments have been used extensively in both agricultural (Santos et al., 1997; Jolliffe et al., 1984; Meekins and McCarthy; 1999) and ecological experiments (Roush et al.; 1989; Roush and Radosevich, 1985; Snyder et al., 1994). This design is used for two main reasons: 1) to determine the better competitor of two species or biotypes, and 2) evaluate the nature of the interaction between two species or biotypes (Cousens, 1991). Replacement series experiments allow comparison of the yield of the mixtures of species with the yield of each species grown in monoculture (Jollife,2000; Radosevich, 1987). There are both advantages and disadvantages of using the substitutive approach. The advantages include: the total plant density being held constant so that only one variable (proportion) changes, predictiveness, and the ability to predict shifts in species composition (Radosevich et al., 1997). Predictiveness (the ability to predict competition) is the main advantage of this type of approach (Radosevich et al., 1997). Replacement series experiments are often criticized because most crops are planted using a constant density rather than variable, making it artificial for field implementation (Radosevich et al., 1997). Replacement series experiments are limited because actual and expected monoculture yields and the outcome of the experiment may vary according to the plant density chosen in the experiment (Radosevich et al., 1997). Also, they cannot be used to separate the effects of interand intraspecific competition (Cousens, 1991) and it is impossible to distinguish between no competition and both species are equally competitive. Relative yield is a valuable calculation that can be obtained from replacement series experiments. Relative yield (RY) and relative yield total (RYT) can be obtained from dry

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18 weights of the individual species and indicates the competitiveness of the individual species (Meekins and McCarthy, 1999) and how the species are using resources in relation to one another (Radosevich et al., 1997). Relative yield values are calculated to compensate for absolute differences in biomass between species and to look at interspecies comparisons (Meekins and McCarthy, 1999). Relative yield can be obtained by using equations 1 and 2 and relative yield total can be derived using equation 3 (Fowler, 1982; McGilchrist and Trenbath, 1971; Meekins and McCarthy, 1999). emonoculturinAspeciesofyieldmixtureinAofspeciesyieldAspeciesRYEqn)1( emonoculturinBspeciesofyieldmixtureinBofspeciesyieldBspeciesRYEqn)2( BspeciesAspeciesRYRYRYTEqn )3( An RYT value of less than one indicates mutual antagonism between the two species. RYT greater than one indicates symbiosis between the two species and no competition between them. When RYT=1 the two species are competing for the same resource (Meekins and McCarthy, 1999). Objectives and Hypotheses The cover crops sunn hemp, velvetbean, and cowpea (cv. Iron Clay) because of their nematode suppressive ability are being evaluated for use in summer fallows as a methyl bromide alternative. The overall objective of our study was to evaluate whether these cover crops can also be utilized to suppress weeds. Specific objectives of greenhouse replacement series experiments were to determine the competitive ability of the three individual cover crops when grown in combination with the two model weed species Cyperus esculentus L. (yellow nutsedge)

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19 and Amaranthus hybridus L. (smooth amaranth). The nutsedge experiment also had an additional objective to determine if the cover crop species would have an effect on the number of tubers produced by the nutsedge. The hypothesis is that the cover crop species will be more competitive than the two weed species and varying growth habits of the cover crop species will have an effect on the weed species. In addition, it is hypothesized that when yellow nutsedge is grown in a high density of cover crop that tuber production will decrease. The specific objectives of additive field experiments were (1) to determine the optimum planting densities of the three leguminous cover crops for suppression of smooth amaranth, (2) to determine the amount of canopy cover produced by the cover crops, (3) to assess cover crop productivity in terms of biomass over the period of the experiment. It was hypothesized that as cover crop density is increased there would be a concomitant decrease in weed biomass until an optimum cover crop density is achieved beyond which no further decrease in weed biomass can be obtained.

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CHAPTER 2 MATERIALS AND METHODS Replacement Series or Greenhouse Experiments Preliminary Greenhouse ExperimentYellow Nutsedge Replacement series experiments were performed during the spring of 2002 in Gainesville, Florida in a greenhouse using combinations of three leguminous cover crop species and yellow nutsedge (Cyperus esculentus L.). Each cover crop species was planted as an individual experiment in a randomized complete block design with four replications. Cover crop species were cowpea (Vigna unguiculata L.) cv. Iron Clay (Wise Seed Company, Frostproof, FL), and sunn hemp (Crotalaria juncea L.) cv. Tropic Sun (Wise Seed company, Frostproof, FL). Due to germination problems, velvetbean (Mucuna deeringiana L.) was not included in this experiment. The cover crop and weed species were planted in five combinations of crop:weed. The proportions used were 100:0, 75:25, 50:50, 25:75, and 0:100. A total plant density of 16 plants was planted in 16x37 cm planter boxes filled with seedlingpre-moistened peat lite mix for tobacco potting soil. Prior to planting imbibed yellow nutsedge tubers were exposed to a heat treatment of 35 C for 1 hour to stimulate sprouting. The cover crop seeds and nutsedge tubers were then planted in the planting pattern (Figure 2-1). The plants were allowed to grow together for 8 weeks. One day prior to harvest, plant heights were measured from the soil surface to the shoot apices of the cover crops. Yellow nutsedge heights were measured from the soil surface to the point at which the blades started to bend over. Photosynthetically active 20

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21 radiation (PAR) was measured using a LI-COR LI-170 Quantum Radiometer/Photometer (LI-COR Inc., Lincoln, Nebraska). These measurements were taken for cowpea both above the canopy and again at the soil surface below the canopy. For sunn hemp PAR was also measured at the middle of the canopy. Measurements were used to derive the percentage of PAR penetrating the canopy. Plants were harvested by block beginning with the sunn hemp treatments over a three day period. Crop and weed above ground biomass were taken separately from each individual box. Leaf area of each species was determined using a LI-COR LI-3100 area meter (LI-COR Inc. Lincoln, Nebraska). Leaves and stems of cover crops and yellow nutsedge were placed in separate paper bags and dried at 72C for 3 days. After drying, tissue was allowed to cool to room temperature and then weighed. Tuber production was also determined at the end of the experiment. Tubers were washed free of soil and tuber number and dry biomass were obtained. Figure 2-1. Greenhouse replacement series planting pattern for all experiments.

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22 Greenhouse ExperimentsYellow Nutsedge Replacement series experiments were performed during fall 2002 and spring 2003 in Gainesville, FL using combinations of three cover crop species and yellow nutsedge. These experiments were conducted as described for the preliminary experiment except for the following changes. The velvetbean cultivar was changed to Georgia Bush (Sharad Phatak, Tifton, Georgia). The seeds of all cover crop species were treated with cowpea inoculant, which is the appropriate rhizobium inoculant for these species (Urbana Laboratories, St Joseph, MO). The planting medium used consisted of 50% vermiculite, 30% sphagnum peat moss, 20% perlite with wetting agents and starter nutrients (Alachua Farm and Lumber Center, Alachua, FL). Greenhouse ExperimentsSmooth Amaranth Replacement series experiments were performed using smooth amaranth (Amaranthus hybridus L.)as the weed species during the spring and summer 2003 in Gainesville, FL. Smooth amaranth experiments were performed in a similar manner as yellow nutsedge experiments except for the following changes. Two weeks prior to planting the cover crops, smooth amaranth seeds were germinated in 10.2 cm pots and then transplanted into 2.5 x 2.5 cm cell seedling trays. Cover crop seeds were planted in the planter boxes in the illustrated planting pattern (Figure 2-1). When the cover crops emerged and were approximately the same height as the amaranth, the amaranth was transplanted into the planter boxes with the cover crop. Preliminary Field Experiment A preliminary field experiment was performed at the North Florida Research and Education Center (NFREC) in Live Oak, FL on Lakeland fine sand soil during the summer of 2002. An additive study was conducted using varying densities of the three

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23 cover crop species and a constant density of smooth amaranth. To reduce the likelihood of infestation by other weeds, two weeks prior to harvest, the field was fumigated with a 67:33 ratio of methyl bromide: chloropicrin at a rate of 448 kg/ha. The experimental design was a split plot with cover crops assigned to the main plots in a randomized complete block design with four replications. Cover crop densities were randomly assigned to subplots, which were 1 m x 8 m in size. Planting was done using a Planet Jr push planter and rhizobium (Urbana Laboratories, St Joseph, Missouri) was applied to the seed just prior to planting according to package directions. Cowpea cv. Iron and Clay (Wise Seed Company, Frostproof, Florida) was planted at 38, 75, 113, 150, 188 plants/m. Sunn hemp cv. Tropic Sun (Wise Seed Company, Frostproof, Florida) was planted at 44, 88, 132, 176, 220 plants/m, and due to germination problems sections of the subplots were replanted one week after initial planting to increase plant stand. Velvetbean (Adams-Briscoe Seed Co., Jackson, Georgia) was planted at 15, 29, 44, 58, 73 plants/m. Within each plot, the row spacing varied depending on the desired density of cover crops (Figure 2-2) with the lowest densities obtained with one row and the highest densities at 5 rows. However, the spacing within the row remained the same for each cover crop. The The smooth amaranth was seeded in trays at 5-10 seeds per cell and subsequently thinned to one seedling per cell. The smooth amaranth was planted three weeks prior to transplanting. At cover crop emergence, about 3 days after planting, smooth amaranth was transplanted into the field in a designated pattern (Figure 2-3) within the plots at a constant density of five plants/M and watered in by overhead

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24 irrigation. The experiment was carried out for a 10-week period and the plots were maintained free of other weed species. Two days prior to biomass harvest, PAR was measured 30.5 cm above the soil surface with a LI-COR 1-m line quantum light sensor (LI-COR Inc., Lincoln, Nebraska 68504). Cover crop heights were measured on the day of harvest from the soil surface to the apex of the stem. The heights were taken at four random points within each plot and averaged to obtain a mean plant height for each plot. The plots were harvested by using a quadrat to randomly select a one m area of the plot. The shoots of the crops and weeds were harvested by cutting at soil level and placed in separate bags. The harvested material from each plot was dried and the dry biomass was obtained. After obtaining the biomass samples, the rest of the plot was cut down and the cover crop residue was retained in the plot as a mulch. At two-week intervals for four weeks, regrowth of cover crops and weed was evaluated. The plots were rated visually for both crop and weed regrowth. Density 1One row of cover crop centered within the plot. ___________________________________ X_________________________________ 50 Density 2Two rows of cover crop spaced 50cm apart within the plot. _______________________X_______________________X_____________________ 25 75 Density 3Three rows of cover crops spaced 33.3cm apart within the plot. ________________X_________________X________________X_________________ 16.65 50 83.3 Density 4Four rows of cover crops spaced 25cm apart within the plot. _____________X______________ _X____________X________________X________ 12.5 37.5 62.5 87.5 Density 5Five rows of cover crops spaced 20cm apart within the plot. _________X____________X___________X_____________X_____________X_____ 10 30 50 70 90 Density 6100% smooth amaranth planted according to planting pattern. Figure 2-2. Planting pattern for cover crop densities: 2002 and 2003.

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25 Figure 2-3. Smooth amaranth planting pattern for additive experiments summer 2002. Field Experiments 2003 Additive field studies were performed at the Plant Science Research and Education Unit (PSREU) in Citra and (NFREC) in Live Oak, summer 2003 using varying densities of the three cover crop species and a constant density of smooth amaranth. Soil type at Citra is a Sparr sand while the soil type at Live Oak is a Lakeland fine sand. These experiments were conducted as described in the preliminary field experiment except for the following changes. Instead of fumigation, a stale seedbed approach using glyphosate was used prior to planting the experiment to reduce infestation of other weeds. The subplots were 1 m x 7 m and cover crop density varied by species. Seeds of the three cover crop species were weighed out as follows: cowpea and sunn hemp1.42 kg and velvetbean2.7 kg. Cowpea rhizobium inoculant (Urbana Laboratories, St Joseph, MO) was applied to the seeds one day prior to planting to cowpea and sunn hemp at a rate of 0.64 g mixed with 6 ml of water and to velvetbean cv. Georgia Bush at a rate of 0.96 g inoculant mixed with 10 ml of water. Inoculant was then applied to the seed and allowed to dry on the seed. Cover crop seeds were planted in Citra on June 30 and smooth amaranth seedlings on July 2: at Live Oak cover crops were planted July 14, with amaranth transplanted on July 15. All cover crops were planted according to the planting

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26 pattern in Figure 2-2. Cowpea cv. Iron Clay was planted and thinned to 10, 20, 30, 40, 50 plants/m. Sunn hemp cv. Tropic Sun was planted at 20, 40, 60, 80, 100 plants/m. Velvetbean cv. Georgia Bush was planted at 10, 20, 30, 40, 50 plants/m. It was not necessary to thin sunn hemp or velvetbean, as populations were attained by the seeding plate used in planting. Smooth amaranth seeds were aerated with an aquarium aerator for 72 hours to imbibe the seeds and break dormancy. Seeds were then scattered in planter boxes to germinate. When the smooth amaranth seedlings were at the two-leaf stage, they were transplanted to 2.5 x 2.5 cm cells in plastic seedling trays. Smooth amaranth was planted in a designated pattern (Figure 2-4) within the plots at a constant density of 15 plants/m. At time of cover crop emergence about 3 days after planting, smooth amaranth was transplanted into the field and watered in by overhead irrigation. The experiment was carried out for a 12-week period and the plots were maintained free of other weed species at Citra. However, an infestation of hairy indigo occurred within the plots in Live Oak and was harvested in addition to the smooth amaranth to determine interference between the cover crops and smooth amaranth occurred due to the presence of this weed. PAR was measured with a LI-COR quantum light sensor (LI-COR Inc., Lincoln, Nebraska), plant height and plant canopy measurements were taken at three, six, nine, and 12 weeks after planting. Heights for both the cover crops and the smooth amaranth were taken at four random points within each plot and averaged to obtain mean plant height for each species. Plant canopy width in two directions was taken from one random plant in each plot. Biomass samples were harvested by randomly selecting a 1m area of plot at six and 12 weeks after planting. The experiment at Citra was harvested on

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27 September 16, with Live Oak harvested October 9. After the 12-week biomass sampling, the remainder of the plot was cut down using a tractor-mounted drum mower at Citra and a walk behind sickle bar mower at Live Oak and the residue left in the plot as a mulch. At two and four weeks after harvest plots were visually rated for weed and crop regrowth. At the end of the 4-week period, a 0.5m sample was taken to determine if there was continued weed suppression of other species when the cover crops were left as mulch in the field. 10cm 20cm8.75cm16.5cm Figure 2-4. Planting pattern of smooth amaranth in additive experiments, summer 2003.

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28 Statistical Analysis Greenhouse Data Analysis of variance (ANOVA) was performed using the PROC GLM procedure of SAS 1 for all parameters to determine significance at the ( 0.05) level. If there was no interaction due to season data were combined. LSMEANS were obtained. Regression was then performed on the means when a significant response occurred due to proportion. Data obtained from the biomass of both the crop and weed species were converted to relative yield (RY) to determine how well the species perform in mixture as compared to the monoculture (Equations 2.1, 2.2). Relative yield total was also calculated to determine how each species contributed to the total yield in mixture (Equation 2.3). Percentage of PAR penetrating the canopy were calculated by dividing PAR below canopy by PAR at the top of the canopy. The leaf areas obtained were used to calculate leaf area index (LAI) as indicated in Equation 2.4. emonoculturinAspeciesofyieldmixtureinAofspeciesyieldAspeciesRYEqn)1.2( emonoculturinBspeciesofyieldmixtureinBofspeciesyieldBspeciesRYEqn)2.2( BspeciesAspeciesRYRYRYTEqn )3.2( boxareaSurfacearealeafTotaLAIEqn)4.2( Field Data Analysis of variance was performed using the PROC MIXED procedure of SAS to determine significance ( 0.05) of main effects and interactions. The three cover crops 1 SAS Software, Statistical Analysis Systems, SAS Campus Drive, Cary, NC 27511

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29 species were analyzed separately due to differences in planting density. Means were then obtained using LSMEANS option in SAS and were subjected to the Proc REG procedure of SAS to determine the response to the effect of density or time. Plant heights were taken at four random points with in the plots and a mean height was obtained for each species in the plots. PAR was expressed as a percentage of the ambient light. Biomass was also compared at 20 and 40 plants/m, densities common to all three species.

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CHAPTER 3 RESULTS AND DISCUSSION Replacement Series Experiments Replacement series experiments were conducted with three legume cover crops and two model weed species yellow nutsedge and smooth amaranth to assess the competitive ability of the cover crops and thus evaluating whether their potential for inhibiting weeds during fallow periods may be due to a highly competitive nature. Yellow Nutsedge and Cowpea Studies with yellow nutsedge and cowpea were conducted in fall 2002 and spring 2003. There was no significant interaction between proportion and season for all variables, except for total crop leaf area, crop LAI, combined leaf area, and dry weight of tubers. The effect of season on each variable is shown in Table 3.1. When treatment was significant, data was also subjected to regression, using the Proc Reg procedure of SAS. Table 3-1. Variables of main effects differences due to season Fall 2002 and Spring 2003. Variable Fall Spring Significance Crop height cm 55.4 42.9 ** Weed height cm 59.7 34.1 *** PAR top of canopy mol m s 289 828 ** PAR soil surface % 23.2 15.6 Tuber number 90.8 251 *** Tubers per plant 8.9 24.5 *** Dry weight tubers per plant g 0.53 2.4 *** Crop leaf area/plant cm 404 2159 *** LAI weed 2.7 2.5 NS Weed leaf area/plant cm 607 596 NS RY crop 0.59 0.81 ** RY weed 0.59 0.76 NS RYT 0.94 1.3 30

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31 Plant Heights Plant heights were taken prior to harvest to assess the effect of the cover crop on the growth of the weed as proportion of crop increased in the mixture. Cowpea and yellow nutsedge heights were significantly higher in fall then spring (Table 3.1). Although the height of cowpea was not significantly affected by the proportion of crop, yellow nutsedge height decreased linearly as proportion of cowpea increased (Table 3.2). Decline in nutsedge height indicates that high proportion of cowpea negatively affects the growth of yellow nutsedge. Table 3-2. Cowpea and yellow nutsedge heights in monoculture and mixture taken at 8 weeks after planting. % crop Crop % Weed Weed cm cm 100 53.3 0 75 48.6 25 35.8 50 48.3 50 43.9 25 46.4 75 48.4 0 100 59.6 Significance NS Significance p 0.05 Slope Slope 0.30 Intercept Intercept 27.95 R R 0.96 PAR PAR measurements were taken below the canopy prior to harvest to determine if the cover crop would decrease the radiation levels reaching the soil surface and thus inhibit the growth of the weed. PAR reaching the soil surface was significantly lower in the spring then fall (Table 3-1). However, PAR reaching the soil surface was not significantly different due to proportion of cowpea in the mixture (Table 3-3).

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32 Table 3-3 PAR measurements taken at soil surface 8 weeks after planting in monoculture and mixture of cowpea and yellow nutsedge. % Crop % PAR Soil Surface 100 19.1 75 21.8 50 22.2 25 19.2 0 14.8 Significance NS Leaf Area and LAI Leaf area was taken to determine how the proportion of cover crop: weed affects the canopy growth of each species and thus the potential for light interception. Leaf area was also used to derive leaf area index (LAI). There was a significant interaction between proportion and season for crop LAI, therefore results are separated by season. Crop LAI decreased linearly during both seasons as the proportion of crop decreased in mixture (Table 3-4). LAI of yellow nutsedge had a linear increase as the proportion of nutsedge increased in mixture. Leaf area per plant did not change with proportion for either species, (Table 3-5). There was a significant interaction between season and proportion for total leaf area of cowpea, therefore, means are separated by season. Total leaf area of yellow nutsedge averaged over season increased linearly with an increase in proportion of the weed in mixture (Table 3-6). Combined leaf area (total leaf area of both spp. together) had a linear increase in both seasons (Table 3-7). During the fall season there was an increase as proportion of nutsedge increased in mixture with combined leaf area lower in both the crop and weed monoculture. However, in the spring there was a significant decrease in leaf area as the proportion of cowpea decreased in mixture, with crop monoculture producing the largest leaf area.

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33 Table 3-4. Leaf area index of cowpea and yellow nutsedge in monoculture and mixture 8 weeks after planting. % Crop LAI Crop % Weed LAI Weed Fall Spring 100 3.1 13.9 0 75 2.3 10.5 25 1.1 50 1.3 8.4 50 2.4 25 0.8 4.4 75 3.2 0 100 3.7 Significance p 0.05 p 0.05 Significance p 0.05 Slope 0.03 0.1 Slope 0.03 Intercept -0.1 1.65 Intercept 0.45 R 0.97 0.98 R 0.93 Table 3-5. Leaf area per plant of cowpea and yellow nutsedge. % Crop Crop % Weed Weed cm cm 100 1175 0 75 1181 25 637 50 1336 50 668 25 1434 75 592 0 100 509 Significance NS Significance NS Table 3-6. Total leaf area of cowpea and yellow nutsedge. % Crop Crop % Weed Weed Fall Spring cm cm 100 6800 30794 0 75 5007 23334 25 2549 50 2071 18605 50 5346 25 1710 9758 75 7098 0 100 8149 Significance p 0.05 p 0.05 Significance p 0.05 Slope 72.83 271.35 Slope 74.2 Intercept -654.75 3663.55 Intercept 1148 R 0.89 0.98 R 0.93

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34 Table 3-7. Combined leaf area: cowpea and yellow nutsedge Fall 2002 and Spring 2003. % Crop Combined Leaf Area Fall Spring cm 100 6800 30794 75 7335 26105 50 7639 23729 25 9068 16597 0 8580 7719 Significance p 0.05 p 0.05 Slope -21.2 222.6 Intercept 8942.8 9857.1 R 0.75 0.93 Tuber Production The number of tubers produced by each mixture was counted and the dry weights were taken to determine if increasing the proportion of cowpea in the mixture would negatively affect the number and size of tubers produced. There was a linear increase in the number of tubers produced as proportion of nutsedge increased in mixture (Table 3-8). However, there was no significant difference in the number of tubers produced per plant. The effect of species proportion on dry weight varied with season (p 0.05). Tuber dry weight was much larger in the spring than in the fall (Table 3-1). A significant linear increase in tuber dry weight was observed in spring 2003. Tuber dry weight was significantly higher in monoculture than in mixture during fall 2003 (Table 3-8). The decrease in tuber production is important because this is how the weed is propagated and a decrease in tuber production will reduce the tuber number in the seed bank, resulting in a decreased population the following season.

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35 Table 3-8. Tuber production 8 weeks after planting for all proportions of cowpea: weed. % Weed Tuber Number Tubers/Plant Dry Weight Per Plant Fall Spring g g 0 25 56.0 14.0 1.8 a 6.9 1.1 50 136 17.6 2.5 a 19.8 1.5 75 208 17.4 3.3 a 34.3 1.6 100 283 17.7 15.9 b 41.8 1.8 Significance p 0.05 NS p 0.05 p 0.05 NS Slope 3.0 0.48 Intercept -17.4 -4.1 R 0.99 0.97 Relative Yield Species dry weights are expressed as relative yield to indicate how each species is performing in mixture relative to performance in monoculture. The relative yield (RY) of cowpea and yellow nutsedge intersected slightly to the left of the 50:50 proportion, indicating that cowpea is slightly less competitive (Figure 3-1). Relative yield total (RYT) was also greater than one, both species contributed more than expected to the total yield when grown in mixture. 100:075:2550:5025:750:100Proportion (Cowpea:Yellow nutsedge) 0.000.300.600.901.201.50Relative yield RYCP RYNS RYT Figure 3-1. Relative yields of cowpea (RYCP) and yellow nutsedge (RYNS) and relative yield total (RYT) eight weeks after planting.

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36 Yellow Nutsedge and Sunn Hemp Where there was significant interaction between proportions and season, data were sorted by season and the simple effects of change in proportion are presented by season. For variables where no interaction occurred, the main effects of season are shown in Table 3-9. Table 3-9. Mean values of sunn hemp for all variables by experiment fall 2002 and spring 2003. Variable Units Fall Spring Significance Crop height cm 96.4 122 *** Weed height cm 53.7 50.4 NS PAR top of canopy mol m s -1 227 708 *** PAR soil surface % 31.9 28.7 NS PAR middle of canopy % 68.1 48.6 ** Tuber number 231 268 NS Tubers per plant 21.7 29.3 Tuber dry weight g 17.6 28.8 ** Dry weight tubers per plant g 1.6 3.0 ** Crop leaf area cm 6406 9376 LAI crop 2.89 4.2 Crop leaf area/plant cm 623 928 ** Weed leaf area/plant cm 663 554 NS RY crop 0.63 0.86 RY weed 0.68 0.99 RYT 1.0 1.5 NS Plant Heights Sunn hemp plants were taller in the spring than in fall, however, yellow nutsedge plants were similar in height both seasons (Table 3-9). Crop heights were not affected significantly by proportion of yellow nutsedge in the mixture (Table 3-10). Similarly, weed height was not significantly affected by the proportion of sunn hemp in the mixture.

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37 Table 3-10. Sunn hemp and yellow nutsedge heights taken at 8 weeks after planting. % Crop Crop Height (cm) % Weed Weed Height (cm) 100 115 0 75 116 25 49.2 50 104 50 53.2 25 101 75 53.1 0 100 52.8 Significance NS Significance NS PAR Due to the tall growth habit of sunn hemp, PAR was measured in the middle of the sunn hemp canopy above the yellow nutsedge, as well as the soil surface. This additional reading was taken to determine the difference in PAR penetration due to canopy. Percentage of PAR penetrating the canopy in the fall was about 3 times greater than in the spring (Table 3-9). There were no significant differences among proportion for the amount of PAR intercepted in the middle or beneath the canopy (Table3-11). Table 3-11. PAR measurements at soil surface taken and middle of sunn hemp canopy 8 weeks after planting. % Crop % PAR Middle Canopy % PAR Soil Surface 100 48.8 39.2 75 56.2 33.8 50 65.2 24.0 25 63.2 30.4 0 24.2 Significance NS NS Leaf Area and LAI LAI of the crop had a significant linear decrease as proportion of crop in the mixture decreased (Table 3-12) and there was no interaction between proportion and season, however the mean LAI of sunn hemp was higher in the spring (Table 3-9). LAI of yellow nutsedge in response to proportion varied with season (p 0.05). There was a significant linear increase as proportion of yellow nutsedge increased in mixture (Table

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38 3-12) for both fall and spring. LAI increased four fold in the fall due to increasing proportion of nutsedge, only increasing slightly less than 1.5 fold in the spring. Table 3-12. Leaf area index of sunn hemp and yellow nutsedge. % Crop LAI Crop % Weed LAI Weed Fall Spring 100 5.4 0 75 4.9 25 1.1 1.7 50 2.6 50 2.8 1.9 25 1.3 75 3.4 2.3 0 100 4.6 2.5 Significance p 0.05 Significance p 0.05 p 0.05 Slope 0.06 Slope 0.04 0.01 Intercept -0.1 Intercept 0.20 1.4 R 0.92 R 0.95 0.97 When looking at leaf area on a per plant basis, there was no significant difference among proportions for either species (Table 3-13). Table 3-13. Leaf area per plant of sunn hemp and yellow nutsedge. % Crop Crop % Weed Weed cm cm 100 744 0 75 919 25 770 50 720 50 652 25 718 75 518 0 100 494 Significance NS Significance NS Total leaf area of sunn hemp in spring 2003 was 30% greater than fall 2002 (Table 3-9). Leaf area was significantly different due to proportion and decreased linearly as proportion of crop decreased in mixture (Table 3-14). There was significant interaction (p 0.05) between season and proportion for total leaf area of yellow nutsedge; therefore, effect of proportion was examined by season. The rate of increase was linear in both seasons as proportion of nutsedge increased for total leaf area of yellow nutsedge (Table 3-14) and the rate of increase in fall was greater then in spring (Table 3-9).

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39 For combined leaf area, the interaction between season and proportion were significant. In fall 2002, combined leaf area was not significantly different due to proportion (Table 3-15). However, in spring 2003, combined leaf area was significantly lower in yellow nutsedge monoculture than all other proportions except when sunn hemp was present at 25%. Table 3-14. Total leaf area of sunn hemp, yellow nutsedge. % Crop Crop % Weed Weed Fall Spring cm cm 100 11907 0 75 11023 25 2503 3655 50 5762 50 6125 4311 25 2873 75 7405 5019 0 100 10272 5536 Significance p 0.05 Significance p 0.05 p 0.05 Slope 129.5 Slope 98.3 28.9 Intercept -199.6 Intercept 429.7 2743.1 R 0.91 R 0.95 0.97 Table 3-15. Combined leaf area sunn hemp and yellow nutsedge. % Crop Combined Leaf Area cm Fall Spring 100 10450 13364 ab 75 10920 17825 a 50 10539 11421 bc 25 9749 8421 cd 0 10272 5536 d Significance NS p 0.05 Tuber Production The number and dry weight of tubers increased linearly by 58 and 52%, respectively, when grown in monoculture compared to sunn hemp and nutsedge were grown in equal proportion (Table 3-16). There was no significant change in the number or dry weight of tubers produced per plant as proportion increased. This indicates that the presence of sunn hemp had no effect on yellow nutsedge tuber production.

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40 Table 3-16. Tuber production 8 weeks after planting for all proportions of nutsedge. % Weed Tuber Number Tubers/Plant Dry Weight Dry Weight/Plant g 0 25 105 26.2 9.0 2.3 50 218 27.2 19.3 2.4 75 303 25.2 28.0 2.4 100 373 23.3 36.5 2.3 Significance p 0.05 NS p 0.05 NS Slope 3.6 0.36 Intercept 26.8 0.40 R 0.98 0.99 Relative Yield The point of intersection for sunn hemp and yellow nutsedge occurred between the 75:25 and 50:50 proportion (Figure 3-2), suggesting that sunn hemp is slightly less competitive than yellow nutsedge. RYT was greater than one for all proportions indicating that both species contributed more than expected to the total yield (Figure 3-2). 100:075:2550:5025:750:100Proportion (Sunn hemp:Yellow nutsedge) 0.000.501.001.502.00Relative yield RYSH RYNS RYT Figure 3-2. Relative yields of Sunn hemp (RYSH) and yellow nutsedge (RYNS) and relative yield total (RYT) eight weeks after planting.

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41 Velvetbean There were no interactions between proportion and season for all variables, except for height of yellow nutsedge. The mean values for both seasons are presented in Table 3-17. Table 3-17. Mean values of velvetbean for all variables by season fall 2002 and spring 2003. Variable Fall Spring Significance Crop height cm 32.8 48.6 *** PAR top of canopy mol m s -1 294 787 *** PAR soil surface % 9.3 5.9 NS Tuber number 208 279 Tubers per plant 19.8 27.1 Tuber dry weight g 15.9 28.7 ** Dry weight tubers per plant g 1.5 2.7 Crop leaf area cm 11772 33499 NS LAI crop 6.6 15.1 NS Crop leaf area/plant cm 1251 3821 NS Weed leaf area cm 5420 7600 NS LAI weed 2.4 3.4 NS Weed leaf area/plant cm 503.3 1009 NS Combined leaf area cm 13754 3210 NS RY crop 0.69 0.69 NS RY weed 0.57 0.72 ** RYT 1.0 1.02 NS Plant Heights Velvetbean was taller in spring 2003 than fall 2002 (Table 3-17), however, crop heights were not significantly different due to proportion of weed in the mixture (Table 3-18). There was a significant proportion by season interaction (p 0.05) for yellow nutsedge height. In the fall, weed height was significantly taller at the 50:50 proportion than the 25:75 proportion however, was not significantly taller than when grown in monoculture (Table 3-18). There was a slightly different response in the spring in which yellow nutsedge was significantly shorter at both the 75:25 and 50:50 proportion than when grown at the 25% proportion or in monoculture.

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42 Table 3-18. Velvetbean and yellow nutsedge heights taken at 8 weeks after planting. % Crop Crop % Weed Weed Fall Spring cm cm 100 40.4 0 75 40.8 25 40.9 a 46.2 a 50 42.2 50 53.9 b 43.9 a 25 39.2 75 47.6 ab 59.0 b 0 100 56.2 b 68.1 b Significance NS Significance p 0.05 p 0.05 PAR PAR measured above the canopy was much greater in the spring (Table 3-17). The presence of velvetbean in the mixture significantly reduced the amount of PAR reaching the soil surface than when yellow nutsedge was grown in monoculture (Table 3-19). Table 3-19. PAR at soil surface taken at 8 weeks after planting. % Crop % PAR Soil Surface 100 4.8 a 75 5.5 a 50 7.7 a 25 6.0 a 0 14.1 b Significance p 0.05 Leaf Area and LAI Leaf areas of both velvetbean and yellow nutsedge were greater in spring 2003 than fall 2002 (Table 3-17). LAI did not change as the proportion of either species increased in mixture (Table 3-20). Leaf area per plant, total leaf area, and combined leaf area were also not significant for either species as proportion of the crop in the mixture increased (Table 3-21 and 3-22).

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43 Table 3-20. Leaf area index per area of box of velvetbean and yellow nutsedge. % Crop LAI Crop % Weed LAI Weed 100 11.6 0 75 8.6 25 2.33 50 18.4 50 2.0 25 4.8 75 3.0 0 100 4.3 Significance NS Significance NS Table 3-21. Leaf area per plant of velvetbean and yellow nutsedge. % Crop Crop % Weed Weed cm cm 100 1818 0 75 1525 25 1299 50 4837 50 568 25 1964 75 560 0 100 599 Significance NS Significance NS Table 3-22. Total leaf area of velvetbean and yellow nutsedge. % Crop Crop % Weed Weed % Crop Combined cm cm cm 100 25687 0 100 24766 75 18305 25 5194 75 23499 50 38693 50 4541 50 43233 25 7856 75 6725 25 14581 0 100 9581 0 9581 Significance NS Significance NS Significance NS Tuber Production There was a significant linear increase in tuber number and tuber dry weight as the proportion of yellow nutsedge in the mixture increased (Table 3-23). When species were grown in equal proportion nutsedge produced 41% fewer tubers than in weed monoculture. Dry weights increased by 38% when grown in monoculture than in equal proportion. Tubers produced per plant were not significantly affected by the proportion of velvetbean in the mixture. Dry weight of tubers did not differ significantly on a per plant basis due to proportion of nutsedge in the mixture (Table 3-23).

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44 Table 3-23. Tuber production 8 weeks after planting for all proportions of nutsedge. % Weed Tuber Number Per Plant Dry Weight Per Plant g 0 25 84.9 21.3 6.4 1.6 50 167 20.9 14.5 1.8 75 315 26.3 30.1 2.5 100 407 25.4 37.9 2.4 Significance p 0.05 NS p 0.05 NS Slope 4.5 0.44 Intercept -35.1 -5.3 R 0.98 0.97 Relative Yield The point of intersection is shifted slightly to the right of the 50:50 proportion (Figure 3-3), indicating velvetbean was slightly more competitive than yellow nutsedge. RYT was also very close to one at all proportions indicating both species contributed equally to slightly more than expected to the total yield. 100:075:2550:5025:750:100Proportion (Velvetbean:yellow nutsedge) 0.000.250.500.751.001.25Relative yield RYVB RYNS RYT Figure 3-3. Relative yields of velvetbean (RYVB) and yellow nutsedge (RYNS) and relative yield total (RYT) eight weeks after planting. Santos et al. (1997) found that tomato was more competitive than yellow nutsedge, similarly these experiments demonstrated that cowpea and sunn hemp were equally to

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45 less competitive than yellow nutsedge and velvetbean was slightly more competitive. Experiments performed by Morales-Payan et al. (2003) indicate that aboveground and belowground interference by yellow nutsedge equally reduce tomato shoot dry weight. Our experiments suggest that the presence of yellow nutsedge also reduced the biomass of cover crops with increased proportion of yellow nutsedge in mixture. The number of nutsedge tubers decreased as the density of cover crop increased in mixture; however, the number of tubers per plant did not change. Santos et al. (1997) also found that the number of tubers produced by yellow nutsedge decreased as the number of plants competing in mixture increased. MoralesPayan et al. (2003) also found that tuber number was reduced by 20% when tomato is present in the mixture under full competition. Holt and Orcutt (1991) found that rapid and early emergence of yellow nutsedge allow avoidance of shading from cotton plants, and so that yellow nutsedge was more competitive than cotton. Smooth Amaranth and Cowpea Cowpea Replacement series experiments were conducted with the three cover crops and an annual broadleaf weed species, smooth amaranth, which is also a common weed in Florida vegetables. For the majority of smooth amaranth and cowpea variables, no interaction between proportion and season except for total leaf area, LAI, and height of smooth amaranth (Table 3-24).

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46 Table 3-24. Mean values of cowpea for all variables by season: spring and summer 2003. Variable Spring Summer Significance Crop height cm 46.2 47.3 NS PAR top of canopy mol m s -1 925 25 529 529 *** *** PAR soil surface PAR soil surface % % 19.0 19.0 11.9 11.9 NS NS Crop leaf area Crop leaf area cm cm 19707 19707 26362 26362 NS NS LAI crop LAI crop 8.9 8.9 11.9 11.9 NS NS Crop leaf area/plant Crop leaf area/plant cm cm 2150 2150 2784 2784 NS NS Weed leaf area/plant Weed leaf area/plant cm cm 148.1 148.1 164.6 164.6 NS NS Combined leaf area Combined leaf area cm cm 16801 16801 21939 21939 NS NS RY crop RY crop 0.76 0.76 0.80 0.80 NS NS RY weed RY weed 1.03 1.03 0.56 0.56 ** ** RYT RYT 1.4 1.4 1.1 1.1 NS NS Plant Heights Height of cowpea was not affected by the proportion of smooth amaranth in the mixture (Table 3-25). There was a significant interaction (p 0.05) between season and proportion; therefore, effect of proportion on weed height is presented by season. During the spring, amaranth heights remained unchanged as proportion of cowpea decreased in mixture (Table 3-25). In summer 2003, smooth amaranth height increased linearly as its proportion increased in mixture. This could be due to the warmer temperatures and higher PAR levels in summer, resulting in greater plant growth (Table 3-24). Table 3-25. Cowpea and smooth amaranth heights taken 8 weeks after planting. % Crop Crop % Weed Weed Spring Summer cm cm 100 48.9 0 75 43.9 25 52.6 50.2 50 46.2 50 44.9 51.0 25 47.9 75 45.8 76.7 0 100 41.3 88.6 Significance NS Significance NS p 0.05 Slope Slope NS 0.56 Intercept Intercept 31.4 R R 0.85

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47 PAR PAR was not significantly different due to proportion of cowpea in mixture (Table 3-26). Table 3-26. PAR taken 8 weeks after planting of cowpea and smooth amaranth. % Crop % PAR Soil Surface 100 12.9 75 13.9 50 8.2 25 26.2 0 16.2 Significance NS Leaf Area and LAI LAI of crop responded with a linear increase as proportion of cowpea increased in mixture (Table 3-27). There was a significant interaction between proportion and season (p 0.05) for LAI of smooth amaranth. Although an interaction occurred between season and proportion, when the means were separated by season there was no significant difference due to proportion. This is probably due to inconsistent magnitude differences among the proportions. Table 3-27. Leaf area index per area of box of cowpea and smooth amaranth. % Crop LAI Crop % Weed LAI Weed Spring Summer 100 13.8 0 75 11.2 25 0.43 0.59 50 10.7 50 0.61 0.40 25 5.9 75 0.77 0.48 0 100 0.52 0.98 Significance p 0.05 Significance NS NS Slope 0.096 Slope Intercept 4.35 Intercept R 0.84 R

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48 Leaf area per plant of crop did not differ significantly due to proportion (Table 3-28). Leaf area of smooth amaranth was significantly greater at the 25:75 proportion than for all other proportions. Table 3-28. Leaf area per plant of cowpea and smooth amaranth. % Crop Crop % Weed Weed cm cm 100 1912 0 75 2072 25 286 a 50 2959 50 140 b 25 3254 75 96.9 b 0 100 103 b Significance NS Significance p 0.05 Total leaf area of cowpea decreased linearly as its proportion in mixture decreased (Table 3-29). Due to the interaction between season and proportion, the effect of proportion on total weed leaf area was assessed by season. Similarly to smooth amaranth LAI (Table 3-29) there was a significant interaction due to season and proportion, however, total weed leaf area was significantly different due to proportion when separated by season (Table 3-29). As the proportion of cowpea decreased in mixture the combined leaf area declined linearly (Table 3-29). Table 3-29. Total leaf area and combined leaf area of cowpea and smooth amaranth. % Crop Crop % Weed Weed % Crop Combined Spring Summer cm cm cm 100 30590 0 100 30590 75 24860 25 949 1313 75 25845 50 23672 50 1357 879 50 24791 25 13015 75 1711 1060 25 14401 0 100 1161 2181 0 1224 Significance p 0.05 Significance NS NS Significance p 0.05 Slope 215.6 Slope 280.7 Intercept 9556.4 Intercept 5334 R 0.85 R 0.85

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49 Relative Yield RY of cowpea is represented by a convex curve and the point of intersection occurred slightly to right of the 50:50 proportion, indicating that cowpea is slightly more competitive than smooth amaranth (Figure 3-4). RYT was greater than one at all proportions. Both species contributed more than expected to the total yield. 100:075:2550:5025:750:100Proportion (Cowpea:smooth amaranth) 0.000.501.001.502.00Relative yield RYCP RYSA RYT Figure 3-4. Relative yields of cowpea (RYCP) and smooth amaranth (RYSA) and relative yield total (RYT) eight weeks after planting. Sunn Hemp There were interactions between proportion and season in the sunn hemp experiment for the following variables: total crop leaf area, LAI crop, crop height, and the combined leaf area (Table 3-30).

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50 Table 3-30. Mean values of sunn hemp for all variables by season: spring and summer 2003. Variable Spring Summer Significance Weed height cm 51.8 89.9 *** PAR top of canopy mol m s -1 590 341 ** % PAR soil surface 31.2 65.1 ** % PAR middle of canopy 49.9 54.9 NS Crop leaf area/plant cm 1067 1525 ** Weed leaf area cm 1568 933 ** LAI weed 0.70 0.42 ** Weed leaf area/plant cm 203 112 ** RY crop 0.64 0.52 ** RY weed 0.98 1.1 NS RYT 1.3 1.3 NS Plant Heights The effect of species proportion in mixture on crop height differed with season (p 0.05). In spring 2003 there was no significant difference due to proportion when means were separated by season (Table 3-31). In summer 2003, there was a significant linear decline in sunn hemp height with increasing proportion of amaranth in mixture. Smooth amaranth was not significantly different among proportions except when species were grown in equal proportion, smooth amaranth was significantly taller than when grown in monoculture. Table 3-31. Sunn hemp and smooth amaranth heights taken 8 weeks after planting. % Crop Crop % Weed Weed Spring Summer cm cm 100 130 229 0 75 139 212 25 71.1 ab 50 123 176 50 77.3 a 25 124 152 75 70.7 ab 0 100 64.1 b Significance NS p 0.05 Significance p 0.05 Slope 1.1 Slope Intercept 125.2 Intercept R 0.97 R

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51 PAR PAR measurements were not significantly different when taken at the middle or bottom of the canopy (Table 3-32). PAR at the soil surface and middle of the canopy did not change in response to change of crop: weed proportion in the mixture. Table 3-32. PAR measurements at soil surface and middle of sunn hemp canopy 8 weeks after planting. % Crop %PAR Middle % PAR Soil Surface 100 53.6 61.6 75 43.9 42.9 50 56.4 29.9 25 55.9 38.5 0 67.8 Significance NS NS Leaf Area and LAI There was a significant proportion by season interaction (p 0.05) for LAI of crop. During both seasons, there is a significant linear decrease in crop LAI as the proportion of sunn hemp decreased in the mixture (Table 3-33). LAI of smooth amaranth was similar with all proportions of crop: weed. Table 3-33. Leaf area index per area of box for sunn hemp and smooth amaranth. % Crop LAI Crop % Weed LAI Weed Spring Summer 100 7.2 12.0 0 75 5.8 8.8 25 0.46 50 3.5 4.9 50 0.66 25 2.2 2.6 75 0.64 0 100 0.47 Significance p 0.05 p 0.05 Significance NS Slope 0.06 0.13 Slope Intercept 0.35 Intercept R 0.98 0.98 R -0.95 Crop leaf area per plant was unchanged in response to proportion of crop in the mixture (Table 3-34). Leaf area per plant of smooth amaranth decreased linearly as

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52 proportion of smooth amaranth increased in the mixture, further indicating that smooth amaranth grows better when in mixture than when in monoculture. Table 3-34. Leaf area per plant of sunn hemp and smooth amaranth. % Crop Crop % Weed Weed cm cm 100 1335 0 75 1347 25 258 50 1168 50 187 25 1334 75 117 0 100 66.9 Significance NS Significance p 0.05 Slope Slope -2.6 Intercept Intercept 318.1 R R 0.99 There was a significant interaction (p 0.05) between season and proportion for total leaf area of sunn hemp. In both spring 2003 and summer 2003, there was a linear decline as proportion of sunn hemp decreased in mixture (Table 3-35). Total leaf area of smooth amaranth did not change in response to crop: weed proportion changes. There was also an interaction between proportion and season (p 0.05) for combined leaf area (Table 3-36). During both seasons, combined leaf area decreased linearly with decreasing proportion of sunn hemp in the mixture. Table 3-35. Total leaf area of sunn hemp and smooth amaranth. % Crop Crop % Weed Weed Spring Summer cm cm 100 16035 26677 0 75 12804 19514 25 1033 50 7861 10830 50 1496 25 4860 5809 75 1404 0 100 1071 Significance p 0.05 p 0.05 Significance NS Slope 153.8 285.2 Slope Intercept 772.4 -2114.7 Intercept R 0.98 0.98 R

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53 Table 3-36. Combined leaf area of sunn hemp and smooth amaranth. % Crop Combined Leaf Area Spring Summer cm m 100 100 16035 16035 26677 26677 75 75 14295 14295 20088 20088 50 50 9550 9550 12132 12132 25 25 6535 6535 6940 6940 0 0 1416 1416 726 726 Significance Significance p 0.05 p 0.05 p 0.05 p 0.05 Slope 147.9 260.2 Intercept 2165.7 302.5 R 0.97 0.99 Relative Yield Sunn hemp was much less competitive than smooth amaranth (Figure 3-5). The point of intersection for the RY of sunn hemp and RY of smooth amaranth is located at the 75:25 indicating sunn hemp must be present at extremely high densities to suppress smooth amaranth. RYT was also consistently greater than one indicating smooth amaranth contributed more than expected when in mixture. 100:075:2550:5025:750:100Proportion (Sunn hemp:smooth amaranth) 0.000.501.001.502.00Relative yield RYSH RYSA RYT Figure 3-5. Relative yields of sunn hemp (RYSH) and smooth amaranth (RYSA) and relative yield total (RYT) eight weeks after planting.

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54 Velvetbean The effect of proportion varied by season for several plant parameters (p 0.05): total leaf area of velvetbean, LAI velvetbean, combined leaf area, height of smooth amaranth, and PAR intercepted below the canopy (Table 3-37). Table 3-37. Mean values of velvetbean for all variables by season: spring and summer 2003. Variable Spring Summer Significance Crop height cm 51.0 61 ** Weed leaf area cm 1130 732 NS LAI weed 0.51 0.33 NS Weed leaf area/plant cm 145 82.2 NS RY crop 0.74 0.73 NS RY weed 1.4 0.8 NS RYT 1.7 1.3 NS Plant Heights Crop heights did not change significantly with increasing proportion of smooth amaranth (Table 3-38). There was a significant interaction between proportion and season for height of smooth amaranth. However, when means were separated by season there was no significant difference due to proportion. Table 3-38. Velvetbean and smooth amaranth heights taken 8 weeks after planting. % Crop Crop % Weed Weed Spring Summer cm cm 100 54.9 0 75 59.1 25 56.3 51.9 50 56.1 50 54.5 38.3 25 53.4 75 51.6 57.8 0 100 36.9 71.2 Significance NS Significance NS NS Slope Slope PAR An interaction occurred between proportion and season for PAR. PAR penetrating the canopy was significantly lower when velvetbean was present in the mixture at all

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55 proportions than when smooth amaranth was grown in monoculture (Table 3-39). In summer 2003, there was a significant linear increase of PAR at the soil surface as proportion of velvetbean decreased in the mixture. Table 3-39. PAR readings taken at soil surface 8 weeks after planting. % Crop % PAR Soil Surface Spring Summer 100 1.3 a 0.9 75 2.7 a 1.2 50 1.4 a 1.6 25 3.9 a 1.7 0 11.9 b 2.1 Significance p 0.05 p 0.05 Slope -0.01 Intercept 2.1 R 0.97 Leaf Area and LAI There was a significant interaction between proportion and season (p 0.05) for LAI of velvetbean. In spring 2003, LAI of velvetbean was significantly lower when grown at 25% of the mixture than all proportions except when grown in equal proportion to smooth amaranth (Table 3-40). However, there was a linear decline with decreasing proportion of velvetbean in summer 2003. LAI of smooth amaranth did not change as proportion of velvetbean changed in the mixture. On a leaf area per plant basis, neither velvetbean nor smooth amaranth was significant as proportion decreased in mixture for either season (Table 3-41). Due to an interaction (p 0.05) between proportion and season, data were separated by season for total leaf area of velvetbean. There was a linear decline as the proportion of velvetbean decreased in mixture for both spring 2003 and summer 2003 (Table 3-42). Smooth amaranth produced a larger leaf area in spring 2003 (Table 3-37).

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56 No significant difference in leaf area occurred due to proportion of smooth amaranth in mixture (Table 3-42). Table 3-40. Leaf area index per area of box of velvetbean and smooth amaranth. % Crop LAI Crop % Weed LAI Weed Spring Summer 100 15.9 a 34.9 0 75 16.2 a 21.7 25 0.36 50 9.9 ab 14.1 50 0.39 25 7.3 b 7.4 75 0.59 0 100 0.35 Significance p 0.05 p 0.05 Significance NS Slope 0.36 Slope Intercept -3.0 Intercept R 0.95 R Table 3-41. Leaf area per plant of velvetbean and smooth amaranth. % Crop Crop % Weed Weed cm cm 100 3585 0 75 3499 25 192 50 3323 50 102 25 4069 75 111 0 100 50.9 Significance NS Significance NS Table 3-42. Total leaf area of velvetbean and smooth amaranth. % Crop Crop % Weed Weed Spring Summer cm cm 100 37138 77593 0 75 35875 48089 25 767 50 21897 31263 50 813 25 16259 16295 75 1329 0 100 814 Significance p 0.05 p 0.05 Significance NS Slope 306.5 802.9 Slope Intercept 8638.7 -6869.9 Intercept R 0.87 0.95 R There was a significant interaction (p 0.05) between proportion and season for combined leaf area. In both spring 2003 and summer 2003, combined leaf area decreased linearly as proportion of velvetbean decreased in mixture (Table 3-43).

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57 Table 3-43. Combined leaf area of sunn hemp and smooth amaranth. % Crop Combined Spring Summer cm m 100 100 37138 37138 77593 77593 75 75 36939 36939 48560 48560 50 50 22890 22890 31896 31896 25 25 18051 18051 17161 17161 0 0 669 669 960 960 Significance Significance p 0.05 p 0.05 p 0.05 p 0.05 Slope 367.3 738.7 Intercept 4772.2 -1698.8 R 0.89 0.97 Relative Yield The point of intersection in the spring is shifted to the left of the 50:50 proportion consistently closer to the 75:25 proportion, indicating that velvetbean is much less competitive than smooth amaranth (Figure 3-6). RY of velvetbean was only greater than smooth amaranth at the 75:25 proportion, meaning a large number of velvetbean plants is needed to suppress a small population of smooth amaranth. RYT was also greater than one, with both species contributing more than expected in mixture. The same trend observed with sunn hemp and cowpea was also seen with velvetbean in which smooth amaranth grows better in mixture than monoculture.

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58 100:075:2550:5025:750:100Proportion (Velvetbean:smooth amaranth) 0.000.501.001.502.002.50Relative yield RYVB RYSA RYT Figure 3-6. Relative yields of velvetbean (RYVB) and smooth amaranth (RYSA) and relative yield total (RYT) eight weeks after planting. This research indicated that smooth amaranth grew better in mixture than when grown in monoculture. Similar results were found with this and other Amaranthus spp (Berry, 2002; Ikeorgu, 1990; Kroh and Stephenson, 1980; Rushing et al., 1985). Results are also similar to Santos et al., (1998) found that smooth amaranth is a better competitor than lettuce, however, they also found that lettuce became more competitive with increased phosphorus fertilizer. Whereas, our results indicated that sunn hemp and velvetbean were less competitive than smooth amaranth and cowpea only slightly more competitive. Soybean yield loss increased with increased weed density of palmer amaranth or redroot pigweed (Bensch et al., 2003).

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CHAPTER 4 RESULTS AND DISCUSSION Additive Experiments Additive field experiments were conducted to determine the optimal planting density of three leguminous cover crops for the suppression of smooth amaranth during the summer fallow between vegetable crops. Preliminary Experiment A preliminary field experiment was conducted in Live Oak, FL during the summer of 2002. Cover crops were planted at fairly high densities ranging from 38 plants/m for cowpea, 44 plants/m for sunn hemp and 15 plants/m for velvetbean. The population of smooth amaranth was relatively low at a density of five plants/m. The results of this study were used to select densities for use in subsequent experiments. Cowpea Crop heights, PAR within the canopy and biomass of crop and smooth amaranth were measured at the end of the ten-week growing season. These variables were examined individually by crop due to variation in plant population of the cover crop species. Cowpea height did not change in response to density (Figure 4-1). PAR was significantly reduced by all densities of cowpea than weed monoculture (p 0.05) (Figure 4-2). Cowpea biomass was the same with all densities (Figure 4-3). Weed biomass decreased as density of cowpea increased with suppression occurring at the 59

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60 lowest density of 38 plants/m with no further change in biomass as cowpea density increased (Figure 4-3). 0255075100125150175200Density (plants/m 2) 0255075100Height (cm) Figure 4-1. Cowpea heights at 10 weeks after planting (WAP). 0255075100125150175200Density (plants/m 2) 050010001500PAR as % ambient (mol m 2s 1) Figure 4-2. PAR within the cowpea canopy 30.5 cm above the soil surface 10 WAP.

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61 0255075100125150175200Density (plants/m2) 02004006008001000Dry Biomass (g m 2) cowpea amaranth Figure 4-3. Biomass of cowpea and smooth amaranth at 10 WAP. Plant Regrowth There was regrowth of plants that had not been cut to the ground for both the cowpea and smooth amaranth (data not shown). Sunn Hemp Sunn hemp heights remained the same (216 cm) as densities were increased from 44 to 220 plants per m (Figure 4-4). PAR measured at 10 weeks decreased quadratically as crop density increased, indicating that less light was available for photosynthesis at higher densities by the smooth amaranth, which was shorter than the sunn hemp (Figure 4-5). Crop dry weights increased linearly as density increased (Figure 4-6); however, amaranth dry weight declined to 11.4 g, with no further change in amaranth dry weight as density increased.

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62 0255075100125150175200225Density (plants/m 2) 0100200300Height (cm) Figure 4-4. Sunn hemp heights at 10 WAP. 0255075100125150175200225Density (plants/m2) 02004006008001000PAR (mol m -2s-1) y = 884 -10.4x + 0.032x R= 0.90 Figure 4-5. PAR within the sunn hemp canopy at 30.5 cm above soil surface 10 WAP.

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63 0255075100125150175200225Density (plants/m2) 030060090012001500Dry Biomass (g/ m 2) sunn hemp amaranth y = 2.9x +581 R= 0.87 Figure 4-6. Biomass of sunn hemp and smooth amaranth 10 WAP. Plant Regrowth Regrowth was minimal for both species and was mainly restricted to plants that had not been cut well (data not shown). Velvetbean Unlike cowpea and sunn hemp, there was a significant linear increase in plant height as density of velvetbean increased. This trend is could be due to the vining growth habit with the ability to twine around surrounding plants (Figure 4-7). PAR decreased quadratically as density of velvetbean increased, with the lowest measurements taken at 58 and 73 plants/m (Figure 4-8). The effect of density on dry weight of velvetbean was not significant (Figure 4-9). Weed biomass with velvetbean was significantly lower than its biomass in monoculture, consistently less than 50 grams. Weed suppression occurred at the lowest density of velvetbean (15 plants/m) with no further change in weed biomass as density increased. This indicated that 15 plants/m was sufficient to suppress smooth amaranth when it occurred at densities of 5 plants/m.

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64 01530456075Density (plants/m2) 0255075Height (cm) y = 0.37x + 33.9 R= 0.87 Figure 4-7. Velvetbean heights at 10 WAP. 01530456075Density (plants/m2) 03006009001200PAR (mols m-2s-1) y = 982.4-23.05x +0.17x R= 0.89 Figure 4-8. PAR within the velvetbean canopy at 30.5cm above soil surface 10 WAP.

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65 015304560Density (plants/m2) 75 050100150200250300350400450500550Dry Biomass (g/ m ) velvetbean amaranth Figure 4-9. Biomass of velvetbean and smooth amaranth 10 WAP. Plant Regrowth Regrowth was minimal for velvetbean and smooth amaranth, similar to cowpea and sunn hemp and was mostly confined to plants that had not been cut well (data not shown). Additive Experiments 2003 Based on the results of the preliminary experiment lower cover crop densities were selected for evaluation in subsequent experiments, and a higher level of weed infestation (15 plants/m) was used. Cowpea The densities used in the preliminary experiment were very effective at suppressing the growth of smooth amaranth. The lowest density of 44 plants/m was sufficient to suppress smooth amaranth, therefore, in the subsequent experiments, cover crop densities were lowered. Cowpea was planted at six densities ranging from 10 to 50 plants/m.

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66 Plant Heights Cowpea plant heights increased significantly until 9 WAP and then a significant decline occurred by 12 WAP (Figure 4-10). This was due to the plants maturing and beginning to set seed. There was significant interaction between location and week for smooth amaranth height, therefore, results are presented by location. Smooth amaranth height at Citra increased as the season progressed up until week six, with no significant difference between six and 9 WAP and were significantly shorter by week 12 (Figure 4-10). At Live Oak, smooth amaranth increased up until 9 WAP and declined by 12 WAP. Shorter heights at week 12 than at week nine may be due to smooth amaranth reaching maturity and beginning to die back. There were no significant differences in cowpea and smooth amaranth height found due to the crop density. 36912Week 020406080Height (cm) cowpea Citra amaranth Live Oak amaranth Figure 4-10. Cowpea height as affected by time and smooth amaranth height as affected by time and location. Crop Canopy Crop canopy was measured at the lowest density of 10 plants/m containing only one row of plants as well as at 30 plants/m with three rows within each plot. A

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67 randomly selected plant from the single row or within the middle row of three-row plots was measured in two directions across the canopy. These two densities were selected to determine how the crop canopy would be affected by the presence or absence of adjacent rows. There was a significant interaction among density, week and location (p 0.05) for crop canopy. Therefore, data were separated by location and density. Crop canopy at Citra and Live Oak increased linearly as the season progressed at 30 plants/m. However, at 10 plants/m canopy increased to its maximum size at week nine at both Citra and Live Oak. A location by week interaction also occurred for weed canopy. At Citra, plant canopy increased peaking at about 8 WAP and declining considerably by 12 WAP (Figure 4-12). Canopy size at Live Oak increased more slowly in a linear manner as the weeks progressed. Therefore, although amaranth plants were still growing in Live Oak 12 weeks after transplanting they had begun to die back at Citra. 36912Week 01000200030004000Canopy (cm2) Citra 10 Live Oak 10 Citra 30 Live Oak 30 y = 380 -1402 R= 0.87 y = 156.8x-179.8 R= 0.90 Figure 4-11. Crop canopy of cowpea as affected by location and density at 10 and 30 plants/ m.

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68 36912Week 0500100015002000Canopy (cm2) Citra Live Oak y =-1633 + 832x-52.7x R= 0.99 y =23x + 9.9 R= 0.90 Figure 4-12. Smooth amaranth canopy as affected by location and week. PAR At Citra by week three, the PAR penetrating to ground level did not change as cowpea density increased (Figure 4-13). However, by week six crop canopy had begun to close at all densities and linear decline in PAR with increasing density occurred so that at the highest density of 50 plants/m PAR was only 15%. By week nine, PAR with densities 30 plants/m was less than 10mol ms as a result of canopy closure at these densities. By 12 weeks the canopy had closed even at the lowest density of 10 plants/m, so that PAR did not differ significantly due to density of cowpea. PAR penetrating the canopy in weed monoculture plots also decreased as the season progressed. At Live Oak, there was a linear decrease in PAR at week three as the density of cowpea increased (Figure 4-14). When measurements were taken at week six the crop canopy had begun to close and there was a dramatic linear decrease in PAR penetrating the canopy as the cowpea density increased. At week nine the lowest PAR levels were attained at 20 plants/m with no further decrease with increased densities indicating that canopy closure had occurred. The final PAR readings at week 12 were lower then at

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69 weeks six and nine for the majority of densities however, there were no significant differences due to density of cowpea. This increase in PAR can be attributed to weather problems in the field including a freeze and severe rainfall, which damaged the plants. 01020304050Density (plants/m2) 0255075100PAR % ambient (mol m 2s 1) 3 wk 6 wk 9 wk 12 wk y= 59.8 3.17x + 0.04x R= 0.91 y = -0.45x + 34.7 R= 0.95 Figure 4-13. PAR penetrating cowpea canopy at Citra as affected by density and time. 01020304050Density (plants/m2) 0255075100PAR as % ambient (mol m 2s1) 3 wk 6 wk 9 wk 12 wk y = -0.42x + 85.58 R= 0 .60 y = -1.13x + 68.87 R = 0.73 y = 54.16-2.83x+ 0.04x R= 0.89 Figure 4-14. PAR penetrating the cowpea canopy at Live Oak as affected by density and time.

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70 Plant Biomass An interaction occurred between density and week for total biomass produced during the season (p 0.05). A linear increase in biomass at week six was observed as density of cowpea increased (Figure 4-15), however, as the plants grew throughout the season the nature of the response changed. At week 12, dry biomass increased quadratically with increased density of cowpea. By 6 WAP cowpea biomass at Citra was about 50% less than at Live Oak (Table 4-1). However, by 12 WAP the more rapid growth of cowpea at Citra resulted in 50% more biomass at Citra than at Live Oak. There was no significant effect of density on amaranth biomass (Table 4-2); however, the main effects of location and week were significant (p 0.05). Weed biomass 120.7 g m at Citra, which was higher than the 12.9 g m recorded at Live Oak. At week six, weed biomass was 73.6 g m and decreased to 60.1 g m by week 12. 1020304050Density (plants/m2) 02004006008001000Dry Biomass (g m -2) 6 wk 12 wk y= 194.50 + 27.5x 0.3x R= 0.93 y = 2.04x + 11.89 R = 0.93 Figure 4-15. Cowpea biomass response to density and week.

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71 Table 4-1. Crop dry weights separated by location. z Week Citra Live Oak Dry Biomass g 6 46.3 a A 99.9 a B 12 875.6 b A 464.6 b B z -Data in columns followed by the same lower case letter and in rows followed by the same upper case letter are not significantly different. Table 4-2. Smooth amaranth biomass by density. Density Biomass g 0 72.4 10 73.6 20 68.0 30 58.3 40 59.6 50 68.9 Significance NS Plant Regrowth Cowpea and weed regrowth were observed two weeks after termination of the cover crops. A biomass sample of the weed population was also taken in a m randomly selected area of each plot to determine the amount of weeds emerging through the cover crop mulch. At Citra, there was a quadratic decrease in regrowth as the density of cowpea increased (Table 4-3). At Live Oak, regrowth was the same with all cowpea densities. There was no weed regrowth observed 2 weeks after harvest. Weed biomass from regrowth was not significantly different in response density of cowpea mulch, four weeks after undercutting.

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72 Table 4-3. Cowpea regrowth 2 and 4 weeks after termination and weed biomass 4 weeks after termination. Density Citra Live Oak Weed Biomass % Crop Regrowth % Crop Regrowth g 0 28.7 10 66.3 3.5 3.5 20 66.9 5.5 5.1 30 65.6 4.3 4.3 40 53.1 8.1 0.6 50 46.9 7.6 5.7 Significance p 0.05 NS NS Intercept 63.1 X 0.5 X -0.01 R 0.89 Sunn Hemp Interactions occurred for all variables between week and location or density and location. Therefore simple effects were evaluated in these situations. Plant Heights Sunn hemp height increased linearly and was accompanied by a linear decrease in smooth amaranth height as sunn hemp density increased (Figure 4-16) at Citra. At Live Oak, plant heights significantly decreased to 40 plants/m and significantly increased from 60 plants/m (Figure 4-16). Smooth amaranth was significantly shorter when sunn hemp was present at 100 plants/m than at 20 plants/m or in monoculture. Sunn hemp plants grew at a faster rate at Citra than at Live Oak (Figure 4-17). With smooth amaranth, there was a significant increase at Citra until week nine and a significant decrease by 12 WAP. At Live Oak, smooth amaranth attained maximum height at 9 WAP and did not change during the remainder of the experiment.

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73 020406080100Density (plants/m2) 050100150Height (cm) Citra SH Live Oak SH Citra SA Live Oak SA y=0.14x+125.4 R= 0.86 y = -0.089x + 45.75 R = 0.95 Figure 4-16. Effects of crop density and location on sunn hemp and smooth amaranth heights. 36912Week 050100150200250300Height (cm) Citra SH Live Oak SH Citra SA Live Oak SA y = 25.67x 60 R = 0.99 y = 16.52x 32.3 R = 0.99 Figure 4-17. Effect of time and location on sunn hemp and smooth amaranth heights. Crop Canopy Plant canopies were larger at Citra than Live Oak, 636 cm, and 347 cm respectively (data not shown), and a larger canopy was produced at the lower density of 20 plants/m (557 cm) than at 60 plants/m (425 cm). Canopy size increased in a linear manner as the season progressed (Figure 4-18). The effect of time on amaranth canopy

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74 size varied by location. The response to canopy at Citra increased to a high of 1467 cm 6 WAP and then significantly decreased to 918 cm by 12 WAP. However, at Live Oak, weed canopy size increased linearly throughout the season (Figure 4-19). 3691Week 2 0100200300400500600700800Canopy (cm2) y= 36.03x+221.03 R= 0.91 Figure 4-18. Effect of time on sunn hemp canopy size. 3691Week 2 0300600900120015001800Canopy (cm2) Citra Live Oak y = 44.9x-18.1 R= 0.85 Figure 4-19. Smooth amaranth canopy size in response to location and week.

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75 PAR There was a significant interaction (p 0.05) among location, density and time for PAR. At Citra, PAR penetrating the canopy at week three decreased linearly as density increased and was much higher than for all other weeks (Figure 4-20). At week six, there was also a linear decrease in PAR with increasing sunn hemp density with a lower percentage of ambient PAR reaching the soil than at week three. There was a quadratic response for weeks nine and twelve due to greater amount of PAR reaching the soil surface in the weed monoculture at weeks nine and 12. The percentage of PAR was lowest between 60 and 100 plants/m. The growth habit of sunn hemp is more upright and less spreading than the cowpea and velvetbean canopies. The canopy closure occurred at higher densities with sunn hemp than with cowpea and velvetbean. 020406080100Density (plants/m2) 0255075100PAR as % ambient (mol m -2s-1) 3 wk 6 wk 9 wk 12 wk 1 2 3 4 Figure 4-20. PAR penetrating the sunn hemp canopy at Citra as affected by density and week. Regression equations: 1) y = -0.17x + 94.38 R = 0.69 2) y = -0.27x + 33.17 R= 0.96 3) y = 57.87 1.30x + 0.008x R = 0.95 4) y = 67.48 .26x + 0.007x R= 0.98

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76 At Live Oak, the PAR reaching the soil surface linearly declined as the density increased up until week nine (Figure 4-21). At week 12, PAR was significantly higher at 40 plants/m than all other densities. 020406080100Density (plants/m 2) 0255075100PAR as % ambient (mol m 2s 1) 3 wk 6 wk 9 wk 12 wk y = -0.24x+94.58 R= 0.97 y = -0.37x+72.2 R= 0.72 y = -0.3 + 55.04 R= 0.88 Figure 4-21. PAR penetrating the canopy of sunn hemp at Live oak as affected by density and week. Plant Biomass Sunn hemp dry weight had a significant three way interaction among density, time, and location. The Citra location at week six had a linear increase in dry biomass as sunn hemp density increased (Figure 4-22). The response at week twelve was quadratic with dry biomass peaking between 80 and 100 plants/m. At Live Oak, the effect of density on dry biomass was not significant (Figure 4-23). Smooth amaranth grew better at Citra producing a total weed biomass of 121.5 g m compared with 22.1 g m at Live Oak. Increasing density of sunn hemp caused a linear decrease in the biomass of smooth amaranth (Figure 4-24). This suggests that further

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77 decline in weed biomass could be achieved with higher densities of sunn hemp than were used in this study. 02040608010Density (plants/m 2) 0 0100020003000Dry Biomass (g/ m 2) week 6 week 12 y = -2.76 + 61.79x 0.34x R= 0.98 y = 3.03x-6.04 R= 0.98 Figure 4-22. Effect of crop density on biomass of sunn hemp taken six and 12 weeks after planting at Citra. 020406080100Density (plants/m2) 0200400600Dry Biomass (g/ m 2) week 6 week 12 Figure 4-23. Effect of density on sunn hemp six and 12 weeks after planting at Live Oak.

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78 020406080100Density (plants/m2) 0255075100125Dry Biomass (g/ m 2) y = 97.4x 0.52 R= 0.88 Figure 4-24. Effect of density of sunn hemp on biomass of smooth amaranth. Plant Regrowth There was a significant interaction between week and location for crop regrowth. At Citra, regrowth was less than 1% and for both times of evaluation (Table 4-4). The regrowth of sunn hemp at Live Oak was also less than 1% at two and four weeks after termination. There was no weed regrowth two weeks after termination of the experiment. At Citra there was a significant quadratic decrease in biomass as density of cover crop increased (Table 4-5). This may be due to larger amounts of crop residue at high crop densities. Weed biomass at Live Oak did not differ significantly due to density of cover crop. Table 4-4. Sunn hemp regrowth 4 weeks after termination of experiment. z Week Citra Live Oak % Crop Regrowth % Crop Regrowth 2 0.2 a 0.25 a 4 0.85 a 0.15 a z means in columns followed by the same letters are not significantly different.

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79 Table 4-5. Weed biomass at 2 and 4 weeks after termination of sunn hemp. Weed Biomass Density Citra Live Oak g g 0 69.2 2.4 10 42.6 15.6 20 10.8 0.98 30 2.4 4.1 40 4.3 7.0 50 3.4 6.2 Significance p 0.05 NS Intercept 70.10 X -3.6 X 0.5 R 0.96 Velvetbean Plant Heights There were two significant interactions (p 0.05) for crop height of velvetbean: week by location and density by week. There was a significant linear increase in crop height as the season progressed at Citra (Figure 4-25). However, at Live Oak, maximum velvetbean height occurred nine WAP and decreased by 12 WAP. For the interaction between density and week, crop heights increased weekly although the effect of density was not significant 3, 6, and 12 WAP (Figure 4-26). 9 WAP, velvetbean grown at 30 plants/m were significantly taller than at all other densities. There were three interactions for smooth amaranth heights when grown in velvetbean: week by location, density by location and density by week. There was a significant difference in smooth amaranth height due to location (Figure 4-27). At Citra maximum smooth amaranth height occurred at 50 cm between weeks six and nine and then decreased to 37 cm 12 WAP. At Live Oak, smooth amaranth reached a maximum height of 35 cm between six and nine weeks and the decreased to 31 cm 12 WAP. For

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80 the density by week interaction, there was significant linear decline in smooth amaranth height at week 12 as density of velvetbean increased (Figure 4-27). Nine WAP smooth amaranth height decreased until 40 plants/m. However, the response was not significant three or six WAP. Although increased velvetbean density caused a linear decrease in smooth amaranth height at Citra (Figure 4-28) the response to density at Live Oak was not significant. 36912Week 020406080Height (cm) Citra VB Live Oak VB Citra SA Live Oak SA y = 6.1x .53 R= 0.98 Figure 4-25. Velvetbean and smooth amaranth heights as affected by week and location.

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81 1020304050Density (plants/m2) 0255075100Height (cm) 3w k 6w k 9w k 12 wk Figure 4-26. Velvetbean heights in response to week and density. 01020304050Density (plants/m2) 0204060Height (cm) 3 wk 6 wk 9 wk 12 wk y = -0.36x + 43.62 R= 0.96 Figure 4-27. Effect of velvetbean density and time on smooth amaranth heights.

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82 010203040Density (plants/m2) 50 0204060Height (cm) Citra Live Oak y = -0.28 + 44 R= 0.88 Figure 4-28. Effect of velvetbean density and location smooth amaranth heights. Plant Canopy Velvetbean canopy over time varied by location and by density. Crop canopy increased linearly at both locations but with a more rapid rate of increase at Citra (Figure 4-29) as well as a linear increase for both measured densities. Canopy size increased more rapidly at 10 plants/m than at 30 plants/m. This can be attributed to more available space for the plants to expand within the row as well as intraspecfic competition at the higher density (Figure 4-30). There was also an interaction for smooth amaranth canopy between week and location. At Citra, smooth amaranth canopy increased to a maximum of 1248 cm at 9 WAP and then decreased to 829 cm by 12 WAP (Figure 4-31); however, the response at Live Oak was not significant. The main effect of density was also significant (p 0.05) with the smallest canopy occurring at 30 plants/m with a canopy of 351 cm, followed by the monoculture at 549 cm, and the greatest canopy of 793 cm at 10 plants/m.

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83 3691Week 2 0100020003000400050006000Canopy (cm2) Citra Live Oak y = 436.3x -826 R= 0.85 y = 271.45 396 R= 0.99 Figure 4-29. Velvetbean canopy size in response to location and time. 36912Week 010002000300040005000Canopy (cm2) 10 plants m 2 30 plants m 2 y = 444.3x 854 R= 0.91 y = 263.46x -367 R= 0.96 Figure 4-30. Effect of time and density on velvetbean canopy size.

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84 3691Week 2 050010001500Canopy (cm2) Citra Live Oak Figure 4-31. Effect of time and location on smooth amaranth canopy size. PAR The effect of density on PAR was dependent on time and location. Percentage of PAR reaching the soil surface decreased dramatically from week three to week six (Figure 4-32). There was a linear decrease in PAR at week three due to increasing density of velvetbean. At week six there was a rapid decrease in PAR until 20 plants/ m to a level of 20 mol m s -1 with no further decline at higher densities. At week nine PAR was significantly lower at all densities than weed monoculture with the lowest PAR occurring at 50 plants/m. At 12 WAP there was a significant decrease in PAR from 70 mol m s -1 with the weed monoculture to 10 mol m s -1 with 10 plants/m with no further decrease in PAR as velvetbean density increased. There was a quadratic decrease at both locations (Figure 4-33) as density of velvetbean increased. The response in PAR over time differed by location. At Citra, PAR declined to its lowest level by week 6 with no further decrease over the next six weeks (Figure 4-34). At Live Oak, PAR declined

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85 linearly as the season progressed. This indicates the canopy closed more rapidly at Citra, than at Live Oak. 01020304050Density (plants/m2) 0255075100PAR as % ambient (mol m 2s 1) 3 wk 6 wk 9 wk 12 wk y = -0.73x + 90.07 R= 0.89 y = 61 -2.26x + 0.03x R= 0.88 Figure 4-32. Effect of crop density and time on PAR beneath the velvetbean canopy. 0102030405Density (plants/m2) 0 0255075100PAR as % ambient (mol m 2s 1) Citra Live Oak y = 80 -2.65x + 0.03x R= 0.79 y = 65 2.99x + 0.042x R= 0.79 Figure 4-33. PAR penetrating the canopy as affected by density and location.

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86 3691Density (plants/m2) 2 0255075100PAR % ambient (mol m 2s 1) Citra Live Oak y = -5.16x + 80.95 R= 0.92 Figure 4-34. Effect of time and location on PAR measured at the base of the canopy. Plant Biomass Velvetbean biomass was significantly greater at Citra than Live Oak for both harvest periods (Table 4-6). This supports the other data, which also indicated that plants were under more favorable growing conditions at Citra. There was a linear increase in crop biomass as density of velvetbean increased (Figure 4-35) with a concomitant decrease in amaranth biomass (Figure 4-36) at both locations. The greatest amaranth suppression occurred with 50 plants/m, the highest density, indicating that in these studies further suppression of amaranth biomass may have been possible at densities greater than 50 plants/m. Table 4-6. Velvetbean dry biomass 6 and 12 weeks after planting. z Week Citra Live Oak Dry Biomass g 6 113.9 a A 80.4 b A 12 811.8 a B 233.0 b B z Data in columns followed by the same uppercase letter and data in rows followed by the same lowercase letter are not significantly different.

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87 01020304050Density (plants/m2) 0200400600800Dry Biomass (g/ m 2) 6 wk 12 wk y = 7.7x +292.1 R= 0.88 y = 2.5x + 22.3 R= 0.97 Figure 4-35. Effect of density on biomass 6 and 12 weeks after planting. 01020304050Density (plants/m2) 050100150200Dry weight (g) Citra Live Oak y = -2.17x + 158 R= 0.92 y = 24.3 +0.10x 0.008x R= 0.87 Figure 4-36. Effect of density on smooth amaranth biomass at Citra and Live Oak. Plant Regrowth Velvetbean regrowth was higher at Citra with plots averaging regrowth of 11.4% and Live Oak only showing a 1.7% regrowth (p 0.05). The effect of density on biomass after cover crop harvest differed with location. At Citra, there was a quadratic

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88 decrease in weed biomass as mulch left by the cover crop increased with density (Table 4-6). At Live Oak, there was a linear decrease in weed biomass with increasing density of cover crop. This may be due to larger amounts of residue provided by the higher densities providing greater suppression of weed growth. Table 4-7. Weed biomass at Citra and Live Oak in response to the density and location. Weed Biomass Density Citra Live Oak g g 0 104 18.7 10 99 4.0 20 4 8 30 0.8 4.4 40 0 2.3 50 0 1 Significance p 0.05 p 0.05 Intercept 117 13.3 X -5.9 -0.2 X 0.07 R 0.76 0.55 Comparison of Cover Crop Biomass at Common Densities There was a significant interaction among density, week and location for biomass when the three cover crops were compared at two common densities of 20 and 40 plants/m (p 0.005). At Citra, there was no significant difference due to crop or density six weeks after planting (Table 4-8). However, at week 12, biomass was significantly less for cowpea and velvetbean than sunn hemp at both 20 and 40 plants/m. Sunn hemp and velvetbean biomass increased by almost 80 and 50% respectively, when grown at the higher density. No change in cowpea biomass occurred with increased density.

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89 Table 4-8. Cover crop biomass at Citra at the 2 common densities (20 and 40 plants/m). z Density Plants/m 20 40 Crop Week Significance y Biomass g/m Cowpea 6 31.7 a 60.2 a NS Sunn hemp 6 50.1 a 111 a NS Velvetbean 6 75.5 a 148 a NS Cowpea 12 803 b 912 b NS Sunn hemp 12 1085 c 1940 c *** Velvetbean 12 665 b 1034 b ** y indicates significant difference between densities for each cover crop z Data in columns followed by the same letter are not significantly different. At Live Oak, there were also no significant differences among cover crops or planting densities at 6 WAP (Table 4-9). At 20 plants/m only sunn hemp and cowpea had significantly greater biomass at 12 WAP than at 6 WAP. Velvetbean biomass was not significantly greater at 12 than six weeks at 20 plants/m. When cover crops were planted at 40 plants/m, cowpea biomass was significantly greater at 12 WAP than at 6 WAP. Sunn hemp biomass did not increase significantly between weeks six and 12. Velvetbean biomass, however, was significantly greater than cowpea and sunn hemp at 12 WAP than 6 WAP, but not greater than sunn hemp at 12 WAP. There were also no significant differences due to density for all cover crops except, sunn hemp at week 12. Biomass of sunn hemp decreased by more than half when grown at the higher density. The poor growth of the cover crops at Live Oak can be attributed to the weather conditions previously mentioned.

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90 Table 4-9. Crop biomass at Live Oak at the 2 common densities (20 and 40 plants/m). z Density Plants/m 20 40 Crop Week Significance y Biomass g/m Cowpea 6 85.5 a 132 a NS Sunn hemp 6 76.7 a 156 a NS Velvetbean 6 61.2 a 103 a NS Cowpea 12 513 c 627 c NS Sunn hemp 12 368 b 174 ab Velvetbean 12 145 a 251 b NS y -Indicates significant difference between densities for each cover crop. z Data in columns followed by the same letter at not significantly different. These experiments suggest that all three cover crops are excellent candidates for use during the summer fallow between vegetable crops. All cover crop species competed well with smooth amaranth in the field. The results of these experiments indicate that cowpea and velvetbean suppress smooth amaranth at fairly low densities with weed suppression occurring as low as 10 plants/m. However, higher cover crop densities were required at higher levels of weed infestation. Similarly, Creamer and Baldwin (2000) found that cowpea and velvetbean reduced weed biomass when compared to weedy control plots, except when crop biomass was extremely low in velvetbean. In the present study the velvetbean canopy became extremely dense by week six, continuing to increase as the season progressed and, therefore, limited the amount of PAR that was available to the weed population and suppressed smooth amaranth growth. Caamal-Maldonado et al. (2001) also found that canopy closure of velvetbean decreases the amount of light reaching the soil and thus inhibiting weed growth. Caamal-Maldonado et al. (2001) found that velvetbean affects the growth of weeds. These results are similar to our findings in which the height and biomass of smooth amaranth were suppressed as density of velvetbean increased. When cover crop residue was left in the field as a mulch, weed biomass was low for all plots containing cover crop

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91 mulch four weeks after termination of the experiment. These results were similar to those of Hutchinson and McGiffen (2000) who found that cowpea mulch reduced weed populations significantly three, five and nine weeks after transplanting pepper into the mulch. In previous reports, weed emergence was lower with cowpea mulch than bareground plots (Hutchinson and McGiffen 2000; Ngouajio et al., 2003). Our results differed from these findings in that although cowpea mulch reduced weed biomass, velvetbean residue had a lower weed biomass four weeks after planting than cowpea, this could be attributed to the allelopathic effects of velvetbean. Results were also similar to Caamal-Maldonado et al. (2001) who also found that velvetbean is a very effective mulch for weed suppression. Although sunn hemp has been used as a cover crop for nematode suppression, no information was found on its use for weed suppression. Our objectives were partially met in the additive experiments. All three leguminous cover crops provided adequate suppression of smooth amaranth. The canopies produced by cowpea and velvetbean became very dense as the season produced and severely limiting PAR reaching the soil surface, and inhibiting weed growth. PAR penetrating the sunn hemp canopy was also reduced as the season progressed, however, PAR increased at the end of the season due to the tall growth habit and less compact canopy. The growth of smooth amaranth was inhibited by the presence of cover crops. Both cowpea and velvetbean suppressed amaranth at the lowest density of 10 plants/m, however, suppression continued to increase with increased density. Sunn hemp provided weed suppression at 20 plants/m, however, when the density is increased to 40 plants/m or higher greater suppression is achieved. All three cover crops continued to suppress weeds when their residue retained as a mulch within the plots. Cowpea and velvetbean

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92 should be planted at densities greater then 30 plants/m and sunn hemp slightly higher at 60 plants/m to obtain optimum weed suppression. Future research needs to be done to determine the effect of the cover crops on the subsequent vegetable crop and to determine how much nitrogen is contributed by the cover crops to the soil at these densities in addition to weed suppression.

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CHAPTER 5 SUMMARY AND CONCLUSIONS A biologically-based, sustainable vegetable production system is under development that utilizes leguminous cover crops (cowpea, sunn hemp, and velvetbean) to suppress plant pathogenic nematodes. Our study attempts to extend the benefit from the cover crops by also utilizing them to suppress weed growth during the summer fallow period. Therefore, the objectives of our studies were: 1) to determine the competitive ability of the three individual cover crops with two model weed species, yellow nutsedge and smooth amaranth; and 2) to determine the optimal planting density of each cover crop for the suppression of smooth amaranth. In greenhouse replacement series experiments, on a relative yield basis, cowpea plants were less competitive than yellow nutsedge, but more competitive than smooth amaranth. Sunn hemp was less competitive than both of the weeds. Velvetbean was slightly more competitive than yellow nutsedge, but less competitive than smooth amaranth. Since these studies were conducted at a single density of 16 plants per box, it is possible that at higher densities or longer periods of interference that the cover crops may prove to be more consistently competitive than the weeds. Although only cowpea was more competitive than smooth amaranth in replacement series experiments in the greenhouse, in field additive experiments the potential for use of cowpea, sunn hemp and velvetbean during summer fallow for weed suppression was clear. In a preliminary experiment in 2002 at Live Oak, the smooth amaranth population planted at 5 plants/m 2 was suppressed by the lowest populations of 93

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94 cowpea, sunn hemp and velvetbean (38, 44, and 15 plants/m 2 respectively). In subsequent experiments in 2003 at Citra and at Live Oak, the cover crop populations were decreased and the smooth amaranth population was increased to 15 plants/m. Cowpea biomass was approximately 50% greater at Citra than at Live Oak 12 weeks after planting (WAP). Cowpea biomass continued to increase with increase in plant density until 30 plants/m with no further increase in biomass at higher densities. However, there was no decline in smooth amaranth biomass as density of cowpea increased. Sunn hemp also grew better at Citra than at Live Oak. At Citra, 12 WAP sunn hemp biomass increased quadratically as density increased to 80 plants/m with no further increase in biomass as density increased to 100 plants/m. However, at Live Oak there were no differences in biomass with increased density. Smooth amaranth biomass decreased by almost 50% when sunn hemp was present at 100 plants/m than when grown in the absence of sunn hemp. However, the linear nature of the response indicated that higher sunn hemp populations (greater than 100 plants/m 2 ) were needed to achieve optimal weed suppression. Velvetbean biomass was considerably larger at Citra than Live Oak. As density of velvetbean increased, its biomass continued to increase at both 6 and 12 WAP. Smooth amaranth continued to decrease as velvetbean densities increased. Although smooth amaranth biomass decreased by nearly three fold at Citra and slightly less than half at Live Oak, optimal suppression did not occur at the highest cover crop density of 50 plants/m.

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95 The mechanism of cover crops suppression of smooth amaranth appears to be rapid canopy closure leading to a reduced availability of PAR for the weed. Retention of residue as mulch after the cover crops were cut down also resulted in continued suppression of weed germination and growth. All 3 cover crops tended to regrow when cut above the soil surface. A method of undercutting the plants just below the soil surface may address this problem. All three species have the potential to be used as cover crops during the summer fallow period depending on the needs of the individual grower. Planting at lower densities in the field will provide adequate suppression when weed infestation is fairly low; however, higher densities of cover crops should be planted when a high infestation of smooth amaranth is anticipated. Increasing cover crop density will increase weed suppression and contribute more biomass to the soil. If a low infestation of weeds is expected (as in the preliminary experiment at 5 plants/m or less), cowpea and velvetbean should be planted at a rate of at least 20 plants/m and sunn hemp at a rate of at least 40 plants/m for suppression of smooth amaranth. However, when the level of weed infestation is predicted to be in excess of 15 plants/m, higher cover crop densities are needed. It is difficult to predict how cowpea will suppress high infestations of smooth because when cowpea was present at 50 plants/m smooth amaranth, when planted at 15 plants/m, was unaffected. Sunn hemp should be planted in excess of 100 plants/m when infestation of smooth amaranth is expected to be high. Optimal weed suppression was not obtained with velvetbean when smooth amaranth was present at 15 plants/m, therefore, velvetbean should be planted at densities greater than 50 plants/m.

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96 The use of cover crops in a biologically-based vegetable production system can suppress nematodes as well as weeds. Other benefits include increased soil N when the cover crops are incorporated at the end of the growing season or the crop residue can be used as an organic mulch for the subsequent crop, thereby reducing the amount of polyethylene mulch that is used in the production of vegetables. This will not only benefit the grower but the environment as well. Using cover crops instead of polyethylene mulch will reduce the economic and environmental costs of disposal. Less polyethylene mulch will need to be disposed of by burning and by placing in landfills. Future research is still needed to determine proper plant spacing and methods of establishment. Benefits to the subsequent crop should also be evaluated to determine the amount of nitrogen produced by the cover crops and how much of this N is available for use by the subsequent crop. The cover crop residues should also be studied to determine the amount of continued weed suppression than can be obtained when retained as mulch as well when the subsequent crop should be planted to most effectively utilize N fixed by the cover crops.

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APPENDIX A PRELIMINARY REPLACEMENT SERIES EXPERIMENT Cowpea and Yellow Nutsedge Materials and methods for this experiment are located in chapter 2 except velvetbean was not included in the study due to germination problems. There was no significant difference in either species height due to an increase or decrease of species in mixture (Table A-1). The LAI of cowpea did not change with change in species proportions (Table A-2). However, LAI of yellow nutsedge did increase linearly as its proportion in mixture rose. Total crop leaf area per planting box and crop leaf area per plant were unaffected by the change in proportion of species in the mixture (Table A-3). Total yellow nutsedge leaf area responded to an increase of proportion in mixture with a linear increase, however, when expressed on a per plant basis there was no significant difference (Table A-3). Tuber production or dry weight were higher in monoculture than all other proportions of crop: weed (Table A-4). There was no significant decrease in PAR reaching the soil surface as density of cowpea decreased in mixture (Table A-5). Table A-1.Cowpea and yellow nutsedge heights taken 8 WAP. % Crop Cowpea % Weed Nutsedge cm cm 100 27.8 0 75 27.4 25 55.1 50 37.3 50 53.6 25 23.8 75 54-4 0 100 59.9 Significance NS Significance NS 97

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98 Table A-2.Cowpea and yellow nutsedge LAI based on area of box. % Crop LAI Crop % Weed LAI Weed 100 22.3 0 75 8.9 25 4.2 50 22.2 50 5.3 25 2.9 75 7.0 0 100 10.4 Significance NS Significance 0.05 Slope Slope 0.88 Intercept Intercept 1.65 R R 0.90 Table A-3. Leaf area and combined leaf area of cowpea and yellow nutsedge. % Crop Crop Total Crop/ Plant % Weed Weed Total Weed/ plant % Crop Combined cm cm cm 100 4898 240 100 100 5788 75 1961 82.2 75 9252 2313 75 11212 50 4878 610 50 11664 1458 50 16542 25 653 163 25 15498 1292 25 16152 0 0 23006 1438 0 23006 Significance NS NS Significance 0.05 NS Significance NS Slope Slope -180.39 Slope Intercept Intercept 21620 Intercept R R 0.90 R Table A-4. Tuber dry weight and tuber production of yellow nutsedge. % Weed Dry Biomass Production g 0 25 31.5 a 238.5 a 50 40.9 a 279.75 a 75 44.7 a 254.2 a 100 85.5 b 481.7 b Significance p 0.05 p 0.05

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99 Table A-5. PAR penetrating to the canopy of cowpea and yellow nutsedge. % Crop % PAR 100 45.2 75 26.7 50 25.7 25 24.8 0 16.9 Significance NS Sunn Hemp and Yellow Nutsedge Sunn hemp plants were significantly lower when grown in equal proportions than all other proportions (Table A-6). Yellow nutsedge height was not significantly different due to the proportion of sunn hemp and yellow nutsedge present in mixture. LAI of sunn hemp was higher in crop monoculture and 75: 25 proportion, than when grown at the 50: 50 and 25: 75 proportions in the mixture (Table A-7). LAI of yellow nutsedge did not change as the proportions of crop: weed changed. Total leaf area of sunn hemp was not significantly different at the 100 and 75: 25 proportion, and was significantly higher than when grown in 50: 50 or 25: 75 proportion of sunn hemp in mixture (Table A-8). When expressed on a per plant basis there were no significant differences among proportions. The total leaf area of yellow nutsedge was not significantly affected by proportion. However, there was a significant difference in leaf area per plant with the lowest leaf area occurring when nutsedge was grown at 25: 75 proportion. Combined leaf area did not respond significantly to changes in crop: weed proportion (Table A-9). As the proportion of yellow nutsedge increased in the mixture there was no significant increase in the number of tubers produced or in tuber dry weight (Table A-10). There was a decrease in the amount of PAR reaching the soil surface as compared to the PAR measured at the

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100 middle of the canopy; however, there was no significant difference due to the presence of sunn hemp (Table A-11). Table A-6. Sunn hemp and yellow nutsedge heights 8 WAP. % Crop Crop % Weed Weed cm cm 100 146 ac 0 75 138 a 25 50.9 50 87 b 50 51.3 25 120 abc 75 51.1 0 100 55.4 Significance p 0.05 Significance NS Table A-7.LAI of sunn hemp and yellow nutsedge based on area of box. % Crop LAI Crop % Weed LAI Weed 100 79.7 a 0 75 75.9 a 25 4.9 50 18.5 b 50 4.8 25 16.0 b 75 8.3 0 100 8.7 Significance p 0.05 NS Table A-8. Leaf area of sunn hemp and yellow nutsedge. % Crop Crop Total Crop/ plant % Weed Weed total Weed/ plant cm cm 100 17530 a 1096 0 75 16703 a 1392 25 11063 2766 a 50 4076 b 510 50 10714 1339 b 25 3515 b 879 75 18461 1538 b 0 100 19347 1209 b Significance p 0.05 NS Significance NS p 0.05 Table A-9. Combined leaf area of sunn hemp and yellow nutsedge. % Crop Combined 100 17529.8 75 27765.9 50 14789.7 25 21975.8 0 19346.8 Significance NS

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101 Table A-10. Tuber dry weight and production. % Weed Dry Weight Production g 0 25 18.3 181.3 50 31.8 147.6 75 42.5 400 100 58.5 416.5 Significance NS NS Table A-11. PAR measured in middle and below the canopy. % Crop % PAR Soil Surface % PAR Middle 100 62.7 5.4 75 73.2 8.9 50 72.4 9.7 25 67.2 7.8 0 51.0 7.9 Significance NS NS

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APPENDIX B HASTINGS ADDITIVE EXPERIMENT The Hastings experiment was planted on July 21, 2003 as described in Chapter 2 additive field experiments. However, unexpected problems arose early on in the experiment, due to residues of herbicides applied during the previous potato season. All cover crops had symptoms of herbicide injury and stunted growth three weeks into the experiment. Therefore, data were taken at three weeks after planting and then again October 13, 2003, 12 weeks after planting. Smooth amaranth did not survive in most plots. The natural occurring weed population included a variety of other weed species such as red weed (Melochia corchorifolia), carpetweed (Mollugo verticillata), tropical spiderwort (Commelina benghalensis), smooth crabgrass (Digitaria ischaemum), portulaca (Portulaca amilis speg), signal grass (Brachiaria platyphylla) and morning glory (Ipomoea spp.). These weeds were also harvested at 12 weeks to determine if the cover crops had an effect on the naturally occurring weed population. Cowpea Cowpea was severely stunted early in the season and had recovered somewhat by 12 weeks. The plants were still not extremely healthy at this point and symptoms of chlorosis and herbicide injury were still visible. Plant Heights Cowpea heights significantly increased 41% for the effect of week. Crop heights were significantly higher when present at 40 plants/m than all other densities except 50 plants/m. Mean crop heights are presented in Table B-1. Weed heights taken at three 102

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103 weeks were also not significantly different in density compared to monoculture. Weed means are also presented in Table B-1. Table B-1. Cowpea mean heights at weeks 3 and 12 and weed height means at week 3. Density Crop Height Weed Height cm 0 5.6 10 33.2 a 5.5 20 35.5 a 7.1 30 33.4 a 6.9 40 36.6 b 7 50 35.3 ab 7 Significance p 0.05 NS PAR There was significant week by density interaction for PAR. PAR decreased linearly at week three as the density of cowpea increased (Figure B-1). Cowpea had recovered somewhat and produced significantly more canopy represented by a quadratic decrease in the percent of PAR reaching the soil surface, leveling out between 40 and 50 plants/m. 01020304050Density (plants/m2) 0255075100PAR % ambient light (mol m -2s-1) 3 wk 12 wk y = -0.4x + 94.03 R= 0.64 y= 75.96x -3.425x + 0.0423 R= 0.93 Figure B-1. Cowpea PAR taken at 3 and 12 weeks after planting.

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104 Plant Biomass Plant biomass also increased linearly as the density of cover crop increased. Indicating that although the plants were damaged they did recover enough to produce a substantial amount of biomass (Figure B-3). Weed biomass also decreased significantly (p 0.05) from monoculture with the presence of cowpea. However, increased density did not result in increased weed suppression. 01020304050Density (plants/m2) 0100200300400500Dry Biomass (g) cowpea amaranth y= 106.18 +13.3x .14x R= 0.90 Figure B-2. Biomass of cowpea and weed population at time of harvest. Plant Regrowth There was a significant difference for cowpea regrowth in which regrowth at week 2 was greater than at week 4. There was also a significant difference in weed regrowth at 2 and 4 weeks (Table B-2).

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105 Table B-2. Regrowth of cowpea and weed population 2 and 4 weeks after cover crop kill. Week Crop regrowth Weed regrowth % regrowth 2 56 a 10 a 4 65 b 25 b Sunn Hemp Sunn hemp recovered fairly well as the season progressed and visible herbicide burn was no longer apparent at 12 weeks. Plant Heights Sunn hemp increased from 16.9 cm at week three to 69.9 cm at week 12. There was no significant difference in plant or weed heights due to an increased density of sunn hemp. Table B-2. represents the mean values of both variables. Sunn hemp heights are an average on both weeks and weed heights taken at week three. Table B-3. Sunn hemp mean heights at weeks 3 and 12 and weed height means at week 3. Density Crop height Weed height cm 0 4.8 20 40.1 5 40 43 6.2 60 41.9 5.6 80 43.9 6.2 100 47.1 7.3 Significance NS NS PAR The interaction between week and density was significant for PAR. PAR penetrating the canopy of sunn hemp responded similarly to cowpea with a linear increase at week three followed by a quadratic decrease at week 12 (Figure B-4) and the

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106 PAR reaching the soil surface did not decrease further when density increased from 60 plants/m to the higher densities of 80 or 100 plants/m. 020406080100Density (plants/m2) 0255075100PAR % ambient light (mol m -2s-1) 3 wk 12 wk y = -0.25x + 95.03 R= 0.97 y = 80.4 -1.91x + 0.01x R= 0.94 Figure B-3. Sunn hemp PAR taken at 3 and 12 weeks after planting. Plant Biomass Similarly to cowpea, sunn hemp biomass also increased linearly with increasing density (Figure B-5). Weed biomass did not decrease due to the presence of sunn hemp. 02040608010Density (plants/m2) 0 02004006008001000Dry Biomass (g) sunn hemp amaranth y = 274.4x +6.01 R= 0.89 Figure B-4. Biomass of sunn hemp and weed population at time of harvest.

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107 Plant Regrowth There was almost no regrowth of sunn hemp (data not shown) and therefore was not significantly different due to density or week. There was a significant interaction between density and week for weed regrowth. For all densities regrowth was significantly less 2 weeks after cover crop kill than at 4 weeks (Table B-4). Table B-4. Regrowth of weed population 2 and 4 weeks after cover crop kill. Density Week 2 Week 4 % weed regrowth 0 15 a 50 b 20 20 a 36 b 40 15 a 28 b 60 18 a 30 b 80 19 a 31 b 100 10 a 21 b Velvetbean Plant Heights Velvetbean heights increased by 48% from 14.2 cm week three to 29.3 cm at week 12. Velvetbean and smooth amaranth heights were not significantly different due to an increased density. Mean values for these variables can be found in Table B-3. Crop heights shown are an average of both weeks and weed heights for week three. Table B-5. Velvetbean mean heights at weeks 3 and 12 and weed height means at week 3. Density Crop height Weed height 0 21.9 5.1 10 23.6 5 20 21.8 8.1 30 21.2 7.7 40 20.4 5.7 50 21.9 8.8 Significance NS NS

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108 PAR The interaction between density and week was significant. There was a significant linear decrease at week three, which was increasingly greater as density of velvetbean increased (Figure B-7). However, at week 12 there was a quadratic decrease of PAR between 20 and 30 plants/m and then increasing at 50 plants/m. This could indicate that plants at higher densities may not have recovered as well from the herbicide injury. 01020304050Density (plants/m2) 0255075100PAR % ambient light (mol m-2s-1) 3 wk 12 wk y = -0.77 + 92.4 R = 0.89 y = 83.09-4.17x +0.06x R= 0.87 Figure B-5. Velvetbean PAR taken at 3 and 12 weeks after planting. Plant Biomass There was a significant response of velvetbean (p 0.05) to density (Figure B-8). However, the regression model was not significant. This indicates that velvetbean did not recover well and were not able to suppress the weed population unless planted at higher densities.

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109 01020304050Density (plants/m2) 0100200300Dry Biomass (g) velvetbean amaranth Figure B-6. Effect of density on biomass of velvetbean and weeds at time of harvest. Plant Regrowth Velvetbean and weed regrowth were significantly greater 4 weeks after cover crop kill than at 2 weeks (Table B-6). Table B-6. Velvetbean and weed regrowth 2 and 4 weeks after cover crop kill. Week Crop regrowth Weed regrowth % regrowth 2 28 a 25 a 4 32 b 34 b

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LIST OF REFERENCES Abdul-Baki, A.A. and J.R Teasdale. 1997. Sustainable production of fresh-market tomatoes and other summer vegetables with organic mulches. U.S. Department of Agriculture, Agricultural Research Service, Farmers Bulletin No.2279, pp 1-23. Revised. Abdul-Baki, A.A., J.R. Teasdale, R. Korcak, D.J. Chitwood, and R.N. Huettel. 1996. Freshmarket tomato production in a low-input alternative system using cover crop mulch. Hortscience 31: 65-69. Barnes, J.P. and A.R. Putnam. 1983. Rye residues contribute to weed suppression in no-tillage cropping systems. Journal of Chemical Ecology 9: 1045-1057. Bensch, C.N., M.J. Horak, D. Peterson. 2003. Interference of redroot pigweed (Amaranthus retroflexus), palmer amaranth (A. palmeri), and common waterhemp (A. rudis) in soybean. Weed Science 51: 37-43. Berry, A.D. 2002. Smooth pigweed (Amaranthus hybridus L.) and Livid amaranth (Amaranthus lividus L.) interference with cucumber (Cucumis sativus L.). Thesis. University of Florida. Birkett, M.A., K. Chamberlain, A.M. Hooper, and J.A. Pickett. 2001. Does allelopathy offer real promise for practical weed management and for explaining rhizosphere interactions involving higher plants? Plant and Soil 232: 31-39. Brunson, K.E., S.C. Phatak, J.D. Gay, and D.R. Summer. 1994. Evaluating velvetbean as part of the crop rotation in sustainable vegetable production. HortScience 29: 428. Buckles, D., B. Triomphe and G. Sain. 1998. Cover crops in hillside agriculture: farmer innovation with mucuna. International Development Research Centre. Ottawa, On, Canada and International Maize and Wheat Improvement Center, Mexico p 218. Capo-chichi, L. J.A., D.B. Weaver, and C.M. Morton. 2002. Agronomic and genetic attributes of velvetbean (Mucuna sp.): an excellent legume cover crop for use in sustainable agriculture. Making Conservation Tillage Conventional: Building a Future on 25 years of Research. Special report no. 1. Alabama Agricultural Experiment Station and Auburn University. pp 314-319. 110

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111 Caamal-Maldonado, J.A., J.J. Jimnez-Osornio, A. Torres-Barragn, and A.L. Anaya. 2001. The use of allelopathic legume cover and mulch species for weed control in cropping systems. Agronomy Journal 93:27-36. Cousens, R. 1991. Aspects of the design and interpretation of competition (Interference) experiments. Weed Technology 5:664-673. Creamer, N.G., and S.M. Dabney. 2002. Killing cover crops mechanically: Review of recent literature and assessment of new research results. Journal of Alternative Agriculture 17: 32-40. Creamer, N.G., and K.R. Baldwin. 2000. An evaluation of summer cover crops for use in vegetable production systems in North Carolina. HortScience 35: 600-603. Creamer, N.G., M.A. Bennett, B.R. Stinner, J. Cardina, and E.E. Regnier. 1996. Mechanisms of weed suppression in cover crop-based production systems. HortScience 31: 410413. Creamer, N.G., B. Plassman, M.A. Bennet, R.K. Wood, B.R. Stinner, and J. Cardina. 1995. A method for mechanically killing cover crops to optimize weed suppression. Journal of Alternative Agriculture 10: 157-162. Davies, D.H.K., A. Christal, M. Talbot, H.M. Lawson, and G.M. Wright. 1997. Changes in weed population in the conversion of two arable farms to organic farming. Proceedings Brighton Crop Protection Conference: Weeds 1-3, 973-978. Doran, J.W., D.C. Coleman, D.F. Bezdicek, and B.A. Stewart (eds). 1994. Defining soil quality for a sustainable environment, Soil Science Society of America Special Publication No. 35. SSSA and ASA Madison, Wis. Dow Agrosciences. Telone C-17 Label. 2003 a. http://www.dowagro.com/webapps/lit/litorder.asp?filepath=label/pdfs/noreg/010-00016.pdf&pdf=true (July 27, 2004). Dow Agrosciences. Telone C-35 Label. 2003 b. http://www.dowagro.com/webapps/lit/litorder.asp?filepath=label/pdfs/noreg/010-01265.pdf&pdf=true (July 27, 2004). Fowler, N. 1982. Competition and coexistence in a North Carolina grassland: III. Mixtures of component species. The Journal of Ecology 70: 77-92. Fujii, Y. 1999. Allelopathy of hairy vetch and mucuna; Their application for sustainable agriculture. In C.H. Chou et al. Biodiversity and Allelopathy From Organisms to Ecosystems in the Pacific pp 289-300. Academia Sinica, Taipei. Gilreath, J.P., J.W. Noling, B.M. Santos. 2004. Methyl bromide alternatives for bell pepper (Capsicum annuum) and cucumber (Cucumis sativus) rotations. Crop Protection 23: 347-351.

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112 Gilreath, J.P., J.P. Jones, J.W. Noling. 1996. Effect of incorporation method on pebulate efficacy under polyethylene mulch in tomato. Proceedings Florida. State Horticultural Society 109: 190-192. Florida State Horticultural Society. Gowan Company. Sandea Label. 2002. http://www.gowanco.com/labels/sec3/sandeasec3.pdf (July 27, 2004). Harper, J.L. 1977. The population biology of plants. Academic Press, London, UK. Holt, J.S., and D.R. Orcutt. 1991. Functional relationships of growth and competitiveness in perennial weeds and cotton (Gossypium hirsutum). Weed Science 39: 575584. Hoffman, M.L., L.A. Weston, J.C. Snyder, and E.E. Regnier. 1996. Allelopathic influence of germinating seeds and seedlings of cover crops on weed species. Weed Science 44:579-584. Hutchinson, C.M., and M.E. McGiffen, Jr. 2000. Cowpea cover crop mulch for weed control in desert pepper production. HortScience, vol. 35: 196-198. Ikeorgu, J.E. 1990. Glasshouse performance of three leafy vegetables grown in mixtures in Nigeria. Scientia Horticulturae 43:181-188. Initiatives Special Edition. Great Lakes Chemical Corporation Agricultural Products Business. 2004. http://www.pnn.wsu.edu/documents/MBallowancesfor2005.rtf (July 23, 2004). Jolliffe, P. 2000. Essay Review: The replacement series. Journal of Ecology 88: 371-385. Jolliffe, P.A., A.N. Minjas, and V.C. Runecles. 1984. A reinterpretation of yield relationships in replacement series experiments. The Journal of Applied Ecology 21:227-243. Jordan, N. 1993. Prospects for weed control through crop interference. Ecological Applications 3: 84-91. Knavel, D.E., J.W. Herron. 1986. Response of vegetable crops to nitrogen rates in tillage systems with and without vetch and ryegrass. Journal of the American Society for Horticultural Science. 111: 502-507. Kroh, G.C., C.N. Stephenson. 1980. Effects of diversity and pattern on relative yields of four michigan first year fallow field plant species. Oecologia. (Berl) 45: 366-371. Lales, J.C., and B.B. Mabbayad. 1983. The potential and establishment method of Crotalaria juncea L. as a green manure for corn (Zea mays L.). Philippine Journal of Crop Science 8:145-147.

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113 Li, Y., H. Bryan, R. Rao, N. Heckert, and T. Olczyk. Summer cover crops for tomato production in south Florida. 1999. http://www.imok.ufl.edu/LIV/groups/cultural/cover/covercr1.htm (July 27, 2004). Li, Y., H. Bryan, and T. Olczyk. Sunn Hemp A cover crop in Florida. EDIS publication SS-AGR-96. 2000. http://edis.ifas.ufl.edu (July 27, 2004). Lu, Y., K.B. Watkins, J.R. Teasdale, and A.A. Abdul-Baki. 2000. Cover crops in sustainable agriculture. Food Reviews International 16: 121-157. Mansoer, Z., D.W. Reeves, and C.W. Wood. 1997. Suitability of sunn hemp as an alternative late summer legume cover crop. Soil Science Society of America Journal 61: 246-253. Masiunas, J.B., L.A. Weston, and S.C. Weller. 1995. The impact of rye cover crops on weed populations in a tomato cropping system. Weed Science 43:318-323. McGilchrist, C.A. and B.R. Trenbath. 1971. A revised analysis of plant competition experiments. Biometrics 27: 659-671. McSorley, R. 1998. Alternative Practices for managing plant parasitic nematodes. American Journal of Alternative Agriculture 13:98-104. McSorley, R. 1999. Host suitability of of potential cover crops for root knot nematodes. Journal of Nematology 31:619-623 McSorley, R. and D.W. Dickson. 1989. Nematode population density increases on cover crops of rye and vetch. Nematropica 19:490-499. McSorley, R. and D.W. Dickson. 1995. Effect of tropical rotation crops on Meloidogyne incognita and other plant-parasitic nematodes. Journal of Nematology 27:535-544. Meekins, J.F., and B.C. McCarthy. 1999. Competitive ability of Alliaria petiolata (garlic mustard, Brassicaceae), an invasive, nonindigenous forest herb. International Journal of Plant Sciences 160: 743-752. Morales-Payan, J.P., W.M. Stall, D.G. Shilling, R. Charudattan, J.A. Dusky, and T.A, Bewick. 2003. Aboveand below ground interference of purple and yellow nutsedge (Cyperus spp.) with tomato. Weed Science 51:181185. National Research Council. 1989. Alternative agriculture. National Academy Press, Washington, DC. Ngouajio, M., M.E. McGiffen Jr, C.M. Hutchinson. 2003. Effect of cover crop and management system on weed populations in lettuce. Crop Protection 22: 57-64.

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114 Noling, J.W. and J.P. Gilreath. Methyl Bromide: Progress and problems identifying alternatives, Volume II. Edis publication ENY49. 2002. http://edis.ifas.ufl.edu/ (July 27, 2004). Osteen, C. Methyl bromide phaseout proceeds: users request exemptions. Amber Waves U.S. Department of Agriculture Economic Research Service. 2003. http://www.ers.usda.gov/AmberWaves/April03/Features/MethylBromide.htm (July 27, 2004). Putnam, A.R., J. DeFrank, and J.P. Barnes. 1983. Exploitation of allelopathy for weed control in annual and perennial cropping systems. Journal of Chemical Ecology 9: 1001-1010. Radosevich, S.R. 1987. Methods to study interactions among crops and weeds. Weed Technology 1:190-198. Radosevich, S.R., J. Holt, and C. Ghersa. 1997 Weed ecology implications for management. Second Edition. Copyright John Wiley and Sons, Inc. Chapter 5: Associations of Weeds and Crops pp 180-201. Rice, E.L. 1974. Allelopathy. Academic, New York. Roush, M.L., S.R. Radosevich, R.G. Wagner, B.D. Maxwell, and T.D. Peterson. 1989. A comparison of methods for measuring effects of density and proportion in plant competition experiments. Weed Science 37: 268-275. Roush, M.L., S.R. Radosevich. 1985. Relationships between growth and competitiveness of four annual weeds. Journal of Applied Ecology 22:895-905. Rushing, D.W., D.S. Murray, and L.M. Verhalen. 1985. Weed interference with cotton (Gossypium hirsutum). II. tumble pigweed (Amaranthus albus). Weed Science 33:815-818. Santos, B.M., J.A. Dusky, W.M. Stall, D.G. Shilling, and T.A. Bewick. 1998. Phosphorus effects on competitive interactions of smooth pigweed (Amaranthus hybridus) and common purslane (Portulaca oleracea) with lettuce (Lactuca sativa). Weed Science 46: 307-312. Santos, B.M., T.A. Bewick, W.M. Stall, D.G. Shilling. 1997. Competitive interactions of tomato (Lycopersicon esculentum) and Nutsedges (Cyperus spp). Weed Science 45: 229-233. Schneider, S.M., E.N. Rosskopf, J.G. Leesch, D.O. Chellemi, C.T. Bull, M. Mazzola. 2003. United States Department of AgricultureAgricultural Research Service research on alternatives to methyl bromide: pre-plant and post harvest. Pest Management Science 59:814-826.

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115 Snyder, K.M., J.M. Baskin, C.C. Baskin. 1994. Comparative ecology of the narrow endemic Echinacea tennesseensis and two geographically widespread congeners: Relative competitive ability and growth characteristics. International Journal of Plant Sciences 155: 57-65. Spreen, T.H., J.J. VanSickle, A.E. Moseley, M.S. Deepak, and L. Mathers. 1995. Use of methyl bromide and the economic impact of its proposed ban on the Florida fresh fruit and vegetable industry. University of Florida Tech. Bulletin 898. Teasdale, J.R. 1996. Contribution of cover crops to weed management in sustainable agricultural systems. Journal of Production Agriculture 9:475-479. Teasdale, J.R., C.E. Beste, and W.E. Potts. 1991. Response of weeds to tillage and cover crop residue. Weed Science 39:195-199. Unger, P.W. and M.F. Vigil. 1998. Cover crop effects on soil water relationships. Journal of Soil and Water Conservation 53: 200-208. United Nations Environmental Programme (UNEP). 1997. 1997 Report on the Economic Viability of Methyl Bromide Alternatives. http://www.unep.org (July 27, 2004) United Phosphorus Inc. Devrinol Label. 2002. http://www.cdms.net/ldat/ld536001.pdf (July 23, 2004). VanSickle, J.J., C. Brewster, T.H. Spreen. Impact of Methyl Bromide ban on the U.S. vegetable industry. EDIS Bulletin 333. 2000. http://edis.ifas.ufl.edu (July 27, 2004). Walz, E. Organic Farming Research Foundation.. Final results of the third biennial national organic farmers survey. 2002. http://www.ofrf.org/publications/survey/1997.html (July 27, 2004). Wang, Q., H. Bryan, W. Klassen, Y. Li, M. Codallo, and A. Abdul-Baki. 2002. Improved tomato production with summer cover crops and reduced irrigation rates. Proceedings Florida State Horticultural Society 115:202-207. Wang, Q.R., W. Klassen, Z.A. Handoo, A. Abdul-Baki, H.H. Bryan, and Y. Li. 2003. Influence of summer cover crops on soil nematodes in a tomato field. Soil and Crop Science Society of Florida Proceedings 62:8691. Webster, T.M., A.S. Csinos, A.W. Johnson, C.C. Dowler, D.R. Sumner, and R.L. Fery. 2001. Methyl Bromide alternatives in a bell pepper squash rotation. Crop Protection 20: 605-614. Weston, L.A. 1996. Utilization of allelopathy for weed management in agroecosystems. Agronomy Journal 88:860-866.

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116 Wilhelm, S.N. Chloropicrin as a soil fumigant. 1996. http://www.ars.usda.gov/is/np/mba/july96/wilhel1.htm (July 27, 2004) Worsham, A.D. 1991. Allelopathic cover crops to reduce herbicide input. Proceedings: Southern Weed Science Society 44:58-69. Zulfadi, M.D., W. Reeves, and C.W. Wood. 1997. Sustainability of sunn hemp as an alternative late-summer legume cover crop. Soil Science Society of America Journal 61: 246-253.

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BIOGRAPHICAL SKETCH Amanda Shea Collins was born February 15, 1979 in Lakeland Florida to Bruce and Judy Collins. She was raised in Plant City, Florida with two brothers Mike and Nathan. In April 2002 she received a Bachelor of Science degree in Environmental Horticulture with a minor in Biology from Florida Southern College. She was accepted into the graduate program at the University of Florida in Fall of 2002 in the Horticultural Sciences department. Amanda has presented at Southern Weed Science Society, Weed Science Society of America, and Florida Weed Science Society meetings. She also attended the Deep South Weed tour in 2003. 117


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Permanent Link: http://ufdc.ufl.edu/UFE0007018/00001

Material Information

Title: Leguminous Cover Crop Fallows for the Suppression of Weeds
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: UFE0007018:00001

Permanent Link: http://ufdc.ufl.edu/UFE0007018/00001

Material Information

Title: Leguminous Cover Crop Fallows for the Suppression of Weeds
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: UFE0007018:00001


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Full Text












LEGUMINOUS COVER CROP FALLOWS FOR THE SUPPRESSION OF WEEDS


By

AMANDA SHEA COLLINS















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


2004

































Copyright 2004

by

Amanda Shea Collins

































I would like to dedicate this thesis to my parents Bruce and Judy for their love and
support while pursuing this endeavor, and my brothers, Mike and Nathan for always
being there for me.















ACKNOWLEDGMENTS

First of all I would like to thank God for giving me the strength and patience to

complete this journey. The time that I have spent in Gainesville have been some of the

best and most challenging times of my life. The friends that I have made here will

always hold a special place in my heart.

I am extremely grateful to Dr. Carlene Chase for giving me the opportunity and

financial support to pursue this degree. I thank her for all of her help and patience during

my time here. I would like to thank my committee members, Dr. Bill Stall and Dr. Chad

Hutchinson for their help and guidance throughout my project. I thank Dr. Greg

MacDonald for being a great professor. I would like to show my appreciation to Jill

Meldrum and Mike Alligood for all of their help in planting and harvesting of my

experiments. It was great to work with the crews at Citra, Live Oak and Hastings. I am

very appreciative for the help of Scott Taylor, Scott Kerr, Bart Herrington, John Morris,

Bob Nielson, and Sam Willingham during my field experiments. Thank you also to Jana

Col in the Statistics Department for help in analyzing data.
















TABLE OF CONTENTS



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

LIST OF TABLES .......................................... viii

LIST OF FIGURES ............................. ............ .................................... xii

A B ST R A C T .................................................................................................... ....... .. xv

CHAPTER

1 INTRODUCTION AND LITERATURE REVIEW ..............................................1...

R eason for P hase O ut ........................ .......................... ................1.....
Chem ical Alternatives for M ethyl Brom ide ............................................ ...............3...
1,3-dichloropropene + chloropicrin (Telone C-35 and C-17) ................................3...
C h lo ro p icrin ............................................................................... . ...................4
H erb icid e s .................................................................................................... .......... 5
Sustainable A agriculture .............. ...... ............. ................................................. 6
C rop and W eed Interference ......................................... ........................ ...............7...
C ov er C rop s ............................................................................... .. . ...................7
A llelo p ath y .......................................................................................................... 9
Cover Crop Species .................................................. 10
Sunn H em p- Crotalariajuncea L .................................................................. 11
Velvetbean-Mucuna deeringiana (Bort) Merr.............................................12
Cow pea- Vigna unguiculata L ...................................................... ................ 13
W ee d C o n tro l .............................................................................................................. 14
Killing Cover Crops........................... .......... ........................ 14
C o m p etitio n ............................................................................................................... 1 5
A additive E xperim ents ......................................... ......................... .............. 16
Replacem ent Series Experim ents ................................................... 16
O objectives and H ypotheses......................................... ........................ ............... 18

2 M A TERIALS AND M ETH OD S .......................................................... ................ 20

Replacement Series or Greenhouse Experiments..................................................20
Preliminary Greenhouse Experiment-Yellow Nutsedge...............................20
Greenhouse Experiments-Yellow Nutsedge................................................22
Greenhouse Experiments-Smooth Amaranth .............................................22









Prelim inary Field E xperim ent .......................................................... ................ 22
F ield E xperim ents 2003 ......................................... ....................... ................ 2 5
Statistical A analysis ................................................................................................ 28
G reenhouse D ata .............................................................................. 28
F ie ld D a ta ............................................................................................................2 8

3 RESULTS AND DISCUSSION ............................................................................... 30

R eplacem ent Series E xperim ents ............................................................ ................ 30
Y ellow N utsedge and C ow pea....................................... ...................... ................ 30
P lant H eights .............................................................................................. 3 1
P A R .............................................................................................................. 3 1
Leaf Area and LAI ..................................................................... 32
Tuber Production ..................................................................... 34
R elative Y ield ............................................................................................. 35
Yellow Nutsedge and Sunn Hemp...........................................................................36
P lant H eights ..............................................................................................36
P A R ..............................................................................................................3 7
Leaf Area and LAI ..................................................................... 37
Tuber Production ..................................................................... 39
R elative Y ield .........................................................................................40
V e lv etb e a n ....................................................................................................4 1
P lant H eights ..............................................................................................4 1
P A R ..............................................................................................................4 2
L eaf A rea and L A I .....................................................................................42
Tuber Production ........................................................................................43
R elative Y ield .........................................................................................44
Smooth Amaranth and Cowpea................................................................................45
C ow pea ................................................................................................... 45
P lant H eights ..............................................................................................46
P A R ..............................................................................................................4 7
L eaf A rea and L A I .....................................................................................47
R elative Y ield .............................................................................................49
S u n n H e m p ...................................................................................................4 9
P lant H eights ..............................................................................................50
P A R .............................................................................................................. 5 1
L eaf A rea and L A I .....................................................................................51
R elative Y ield .............................................................................................53
V e lv etb e a n ....................................................................................................5 4
P lant H eights ..............................................................................................54
P A R ..............................................................................................................5 4
L eaf A rea and L A I .....................................................................................55
R elative Y ield .........................................................................................57

4 RESULTS AND DISCUSSION................................................................ ...............59

A additive E xperim ents ...................................................................... . ....................59









P relim inary E xperim ent ...................................................................... ................ 59
C ow pea ................................................................................. ...................... 59
Plant R egrow th ............................................................................................... 61
S u n n H e m p ..........................................................................................................6 1
Plant R egrow th ............................................................................................... 63
V elvetbean ..................................................................................................... 63
Plant R egrow th ............................................................................................... 65
A dditive Experim ents 2003 .....................................................................................65
C o w p e a .......................................................................................................................6 5
Plant H eights ................................................................................................. 66
C ro p C a n o p y ........................................................................................................6 6
P A R .....................................................................................................................6 8
P la n t B io m a ss ......................................................................................................7 0
Plant R egrow th ............................................................................................... 71
Sunn H em p .............. ........................................................................ . ......72
Plant H eights ................................................................................................. 72
C rop C anopy ................................................................................................... 73
P A R .....................................................................................................................7 5
P la n t B io m a ss ......................................................................................................7 6
Plant R egrow th ............................................................................................... 78
V elvetbean .............. ........................................................................ . ..... 79
Plant H eights ................................................................................................. 79
Plant C anopy ................................................................................................. 82
P A R .....................................................................................................................8 4
P la n t B io m a ss ......................................................................................................8 6
Plant R egrow th ................................................................................ ..................87
Comparison of Cover Crop Biomass at Common Densities ............................... 88

5 SUMM ARY AND CONCLUSIONS......................................................................93

APPENDIX

A PRELIMINARY REPLACEMENT SERIES EXPERIMENT .............................97

B HASTINGS ADDITIVE EXPERIM ENT ................................................................ 102

LIST OF RE FERE N CE S ...........................................................................................110

B IO G R A PH IC A L SK ETCH ...................................................................... ...............117















LIST OF TABLES


Table page

3-1 Variables of main effects differences due to season Fall 2002 and Spring 2003.....30

3-2 Cowpea and yellow nutsedge heights in monoculture and mixture taken at 8
w weeks after planting. ............. ................ .............................................. 31

3-3 PAR measurements taken at soil surface 8 weeks after planting in monoculture
and mixture of cowpea and yellow nutsedge. ..................................... ................ 32

3-4 Leaf area index of cowpea and yellow nutsedge in monoculture and mixture 8
w weeks after planting. ............. ................ .............................................. 33

3-5 Leaf area per plant of cowpea and yellow nutsedge ........................... ................ 33

3-6 Total leaf area of cowpea and yellow nutsedge. ................................. ................ 33

3-7 Combined leaf area: cowpea and yellow nutsedge Fall 2002 and Spring 2003.......34

3-8 Tuber production 8 weeks after planting for all proportions of cowpea: weed. ......35

3-9 Mean values of sunn hemp for all variables by experiment fall 2002 and spring
2 0 0 3 ........................................................................................................ ........ .. 3 6

3-10 Sunn hemp and yellow nutsedge heights taken at 8 weeks after planting. .............37

3-11 PAR measurements at soil surface taken and middle of sunn hemp canopy 8
w weeks after planting. ............. ................ .............................................. 37

3-12 Leaf area index of sunn hemp and yellow nutsedge ........................... ................ 38

3-13 Leaf area per plant of sunn hemp and yellow nutsedge. ............... ..................... 38

3-14 Total leaf area of sunn hemp, yellow nutsedge................................... ................ 39

3-15 Combined leaf area sunn hemp and yellow nutsedge .........................................39

3-16 Tuber production 8 weeks after planting for all proportions of nutsedge .............40

3-17 Mean values of velvetbean for all variables by season fall 2002 and spring 2003. .41









3-18 Velvetbean and yellow nutsedge heights taken at 8 weeks after planting .............42

3-19 PAR at soil surface taken at 8 weeks after planting ...........................................42

3-20 Leaf area index per area of box of velvetbean and yellow nutsedge. ....................43

3-21 Leaf area per plant of velvetbean and yellow nutsedge. .....................................43

3-22 Total leaf area of velvetbean and yellow nutsedge. ............................ ................ 43

3-23 Tuber production 8 weeks after planting for all proportions of nutsedge .............44

3-24 Mean values of cowpea for all variables by season: spring and summer 2003........46

3-25 Cowpea and smooth amaranth heights taken 8 weeks after planting....................46

3-26 PAR taken 8 weeks after planting of cowpea and smooth amaranth....................47

3-27 Leaf area index per area of box of cowpea and smooth amaranth........................47

3-28 Leaf area per plant of cowpea and smooth amaranth..........................................48

3-29 Total leaf area and combined leaf area of cowpea and smooth amaranth .............48

3-30 Mean values of sunn hemp for all variables by season: spring and summer 2003. .50

3-31 Sunn hemp and smooth amaranth heights taken 8 weeks after planting...............50

3-32 PAR measurements at soil surface and middle of sunn hemp canopy 8 weeks
after p lan tin g ........................................................................................................... 5 1

3-33 Leaf area index per area of box for sunn hemp and smooth amaranth ................. 51

3-34 Leaf area per plant of sunn hemp and smooth amaranth.....................................52

3-35 Total leaf area of sunn hemp and smooth amaranth............................ ................ 52

3-36 Combined leaf area of sunn hemp and smooth amaranth. ..................................53

3-37 Mean values of velvetbean for all variables by season: spring and summer 2003. .54

3-38 Velvetbean and smooth amaranth heights taken 8 weeks after planting............... 54

3-39 PAR readings taken at soil surface 8 weeks after planting. ................................55

3-40 Leaf area index per area of box of velvetbean and smooth amaranth...................56

3-41 Leaf area per plant of velvetbean and smooth amaranth....................................56

3-42 Total leaf area of velvetbean and smooth amaranth.............................. .............. 56









3-43 Combined leaf area of sunn hemp and smooth amaranth. ..................................57

4-1 Crop dry w eights separated by location ............................................. ................ 71

4-2 Sm ooth am aranth biom ass by density ................................................ ................ 71

4-3 Cowpea regrowth 2 and 4 weeks after termination and weed biomass 4 weeks
after term in action ...................................................................................................... 72

4-4 Sunn hemp regrowth 4 weeks after termination of experiment. z .........................78

4-5 Weed biomass at 2 and 4 weeks after termination of sunn hemp .........................79

4-6 Velvetbean dry biomass 6 and 12 weeks after planting. z............. ................86

4-7 Weed biomass at Citra and Live Oak in response to the density and location. .......88

4-8 Cover crop biomass at Citra at the 2 common densities (20 and 40 plants/m2).....89

4-9 Crop biomass at Live Oak at the 2 common densities (20 and 40 plants/m2). ....... 90

A-i Cowpea and yellow nutsedge heights taken 8 WAP...........................................97

A-2 Cowpea and yellow nutsedge LAI based on area of box ....................................98

A-3 Leaf area and combined leaf area of cowpea and yellow nutsedge .........................98

A-4 Tuber dry weight and tuber production of yellow nutsedge. ..............................98

A-5 PAR penetrating to the canopy of cowpea and yellow nutsedge ..........................99

A-6 Sunn hemp and yellow nutsedge heights 8 WAP. ...................... ...................100

A-7 LAI of sunn hemp and yellow nutsedge based on area of box.............................100

A-8 Leaf area of sunn hemp and yellow nutsedge. .....................................100

A-9 Combined leaf area of sunn hemp and yellow nutsedge...................................100

A-10 Tuber dry weight and production. ...... ...... ..... ..................... 101

A-11 PAR measured in middle and below the canopy........................ .................. 101

B-i Cowpea mean heights at weeks 3 and 12 and weed height means at week 3 ....... 103

B-2 Regrowth of cowpea and weed population 2 and 4 weeks after cover crop kill.... 105

B-3 Sunn hemp mean heights at weeks 3 and 12 and weed height means at week 3... 105

B-4 Regrowth of weed population 2 and 4 weeks after cover crop kill..................... 107









B-5 Velvetbean mean heights at weeks 3 and 12 and weed height means at week 3... 107

B-6 Velvetbean and weed regrowth 2 and 4 weeks after cover crop kill................... 109















LIST OF FIGURES


Figure page

2-1 Greenhouse replacement series planting pattern for all experiments....................21

2-2 Planting pattern for cover crop densities: 2002 and 2003...................................24

2-3 Smooth amaranth planting pattern for additive experiments summer 2002. ...........25

2-4 Planting pattern of smooth amaranth in additive experiments, summer 2003 ........27

3-1 Relative yields of cowpea (RYCP) and yellow nutsedge (RYNS) and relative
yield total (RYT) eight w eeks after planting....................................... ................ 35

3-2 Relative yields of Sunn hemp (RYSH) and yellow nutsedge (RYNS) and
relative yield total (RYT) eight weeks after planting.......................... ................ 40

3-3 Relative yields of velvetbean (RYVB) and yellow nutsedge (RYNS) and
relative yield total (RYT) eight weeks after planting.......................... ................ 44

3-4 Relative yields of cowpea (RYCP) and smooth amaranth (RYSA) and relative
yield total (RYT) eight w eeks after planting....................................... ................ 49

3-5 Relative yields of sunn hemp (RYSH) and smooth amaranth (RYSA) and
relative yield total (RYT) eight weeks after planting.......................... ................ 53

3-6 Relative yields of velvetbean (RYVB) and smooth amaranth (RYSA) and
relative yield total (RYT) eight weeks after planting.......................... ................ 58

4-1 Cowpea heights at 10 weeks after planting (WAP). ...........................................60

4-2 PAR within the cowpea canopy 30.5 cm above the soil surface 10 WAP ............60

4-3 Biomass of cowpea and smooth amaranth at 10 WAP .......................................61

4-4 Sunn hem p heights at 10 W A P ........................................................... ................ 62

4-5 PAR within the sunn hemp canopy at 30.5 cm above soil surface 10 WAP. ..........62

4-6 Biomass of sunn hemp and smooth amaranth 10 WAP..................................63

4-7 V elvetbean heights at 10 W A P ...............................................................................64









4-8 PAR within the velvetbean canopy at 30.5cm above soil surface 10 WAP .............64

4-9 Biomass of velvetbean and smooth amaranth 10 WAP ......................................65

4-10 Cowpea height as affected by time and smooth amaranth height as affected by
tim e an d lo catio n ..................................................................................................... 6 6

4-11 Crop canopy of cowpea as affected by location and density at 10 and
3 0 p la n ts/ m 2............................................................................................................ 6 7

4-12 Smooth amaranth canopy as affected by location and week...............................68

4-13 PAR penetrating cowpea canopy at Citra as affected by density and time..............69

4-14 PAR penetrating the cowpea canopy at Live Oak as affected by density and
tim e ....................................................................................................... . ....... .. 6 9

4-15 Cowpea biomass response to density and week.................................. ................ 70

4-16 Effects of crop density and location on sunn hemp and smooth amaranth
h e ig h ts .................................................................. ................................................ ... 7 3

4-17 Effect of time and location on sunn hemp and smooth amaranth heights .............73

4-18 Effect of tim e on sunn hem p canopy size ........................................... ................ 74

4-19 Smooth amaranth canopy size in response to location and week..........................74

4-20 PAR penetrating the sunn hemp canopy at Citra as affected by density and
w e e k .................................................................................................................... . 7 5

4-21 PAR penetrating the canopy of sunn hemp at Live oak as affected by density
a n d w e e k ................................................................................................................ .. 7 6

4-22 Effect of crop density on biomass of sunn hemp taken six and 12 weeks after
p lan tin g at C itra ........................................................................................................ 7 7

4-23 Effect of density on sunn hemp six and 12 weeks after planting at Live Oak ........77

4-24 Effect of density of sunn hemp on biomass of smooth amaranth. .........................78

4-25 Velvetbean and smooth amaranth heights as affected by week and location ..........80

4-26 Velvetbean heights in response to week and density .........................................81

4-27 Effect of velvetbean density and time on smooth amaranth heights ........................ 81

4-28 Effect of velvetbean density and location smooth amaranth heights ......................82









4-29 Velvetbean canopy size in response to location and time................ ................83

4-30 Effect of time and density on velvetbean canopy size ........................................83

4-31 Effect of time and location on smooth amaranth canopy size ..................................84

4-32 Effect of crop density and time on PAR beneath the velvetbean canopy ................85

4-33 PAR penetrating the canopy as affected by density and location ............................85

4-34 Effect of time and location on PAR measured at the base of the canopy ............... 86

4-35 Effect of density on biomass 6 and 12 weeks after planting ....................................87

4-36 Effect of density on smooth amaranth biomass at Citra and Live Oak................. 87

B-I Cowpea PAR taken at 3 and 12 weeks after planting. ................ ...................103

B-2 Biomass of cowpea and weed population at time of harvest. ..............................104

B-3 Sunn hemp PAR taken at 3 and 12 weeks after planting .................................106

B-4 Biomass of sunn hemp and weed population at time of harvest ......................... 106

B-5 Velvetbean PAR taken at 3 and 12 weeks after planting .................................108

B-6 Effect of density on biomass of velvetbean and weeds at time of harvest.......... 109















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

LEGUMINOUS COVER CROP FALLOWS FOR THE SUPPRESSION OF WEEDS

By

Amanda Shea Collins

August 2004

Chair: Carlene A. Chase
Major Department: Horticultural Sciences

Cover crops are becoming an important component in both sustainable agriculture

and organic vegetable production. The use of cover crops during summer fallow periods

has many advantages including weed and nematode suppression, protection from soil

erosion, and the contribution of soil organic matter. The leguminous cover crops used in

this study give the added benefit of enhancing soil nitrogen and have been shown to be

nematode suppressive. Greenhouse replacement series experiments were performed in

Gainesville, FL, in 2002 and 2003 to evaluate the competitiveness of the cover crops

cowpea (Vigna unguiculata cv Iron and Clay), sunn hemp (Crotalariajuncea), and

velvetbean (Mucuna deeringiana) when grown in combination with two model weed

species, yellow nutsedge (Cyperus esculentus) and smooth amaranth (Amaranthus

hybridus). With yellow nutsedge the effect of the cover crops on tuber production was

also evaluated. Cowpea and sunn hemp were found to be slightly less competitive and

velvetbean was slightly more competitive than yellow nutsedge. Increasing the

proportion of the cover crops in the crop:weed mixture from 25:75 to 75:25 did not









significantly affect tuber number or tuber weight per nutsedge plant. Cowpea was

slightly more competitive than smooth amaranth and both sunn hemp and velvetbean

were much less competitive than smooth amaranth.

Additive field experiments were performed to determine the optimum cover crop

populations for suppression of smooth amaranth. In a preliminary experiment at the

North Florida Research and Education Center (NFREC) in Live Oak, FL, in 2002 a range

of cover crop densities was evaluated in mixtures with smooth amaranth at a constant

density of 5 plants/m2. After 10 weeks on a dry biomass basis, smooth amaranth was

suppressed by cowpea, sunn hemp, and velvetbean at the lowest populations (38, 44, and

15 plants/m2 respectively), with no further decrease in biomass as cover crop population

increased. Based on these results, in 2003 at the Plant Science Research and Education

Unit (PSREU) in Citra and NFREC in Live Oak, cover crop densities were lowered and

smooth amaranth population was increased to 15 plants/m2. Cowpea density had no

effect on smooth amaranth biomass in these experiments. However, smooth amaranth

biomass declined linearly as sunn hemp density increased so that smooth amaranth

biomass was 51% lower with 100 sunn hemp plants/m2 than in the absence of sunn hemp.

Similarly with increasing density of velvetbean, biomass and a linear decrease in smooth

amaranth biomass at PSREU; however, at NFREC there was a quadratic decrease in

smooth amaranth biomass with maximum suppression occurring at the highest density of

50 plants/m2. Although these cover crop species were not consistently more competitive

in the greenhouse experiments, planting densities can be manipulated to obtain adequate

smooth amaranth suppression in the field. Higher cover crop densities will be needed

with larger weed infestations.














CHAPTER 1
INTRODUCTION AND LITERATURE REVIEW

There is an impending ban on methyl bromide use in the U.S. Therefore, it is

important that alternatives are found to suppress both weed and nematode populations.

There is a need for both chemical and non-chemical alternatives. The use of cover crops

during summer fallow can be a viable alternative for both conventional and organic

growers.

Methyl bromide is one of the most popular broad spectrum soil fumigants currently

used by farmers and is an important fumigant utilized in world vegetable production. It is

used to suppress soil-borne diseases, nematodes, insects and weeds in more than 100

crops, ornamental nurseries, forestry, and wood products (Schneider et al., 2003). Methyl

bromide is currently being phased out and the most recent phase out date of January 2005

has been extended. The vegetable industry will be severely impacted as a result of this

phase out, unless, suitable alternatives to this fumigant are identified. The Montreal

Protocol acknowledged that there were no suitable alternatives for many applications,

therefore the phase out has been extended (Initiatives, 2004). These decisions indicate

that methyl bromide will be available beyond 2005 until viable alternatives are available.

Research is currently being performed on both chemical and non-chemical alternatives.

Reason for Phase Out

Methyl bromide was designated by the Montreal Protocol of 1991 to be an ozone-

depleting chemical. In accordance with this definition, methyl bromide manufacturing

and importation in developed countries was scheduled for phase out as follows:









25% reduction in 1999

50% reduction in 2001

70% reduction in 2003

100% reduction in 2005

Exemptions for developed and developing countries include certain pre-shipment

uses, critical use and quarantine uses (Schneider et al., 2003). Consumption for

developing countries varies from that of developed countries. Developing countries had

a freeze imposed in 2002 at 1995-1998 average levels, a 20% reduction in 2005 and

phase out completion in 2015 (Schneider et al., 2003). Developed and developing

countries can file for exemptions, including critical uses, quarantine and certain

preshipment uses (Schneider et al., 2003).

Methyl bromide has been identified as critical for the production and marketing of

many fruit and vegetable crops (VanSickle et al., 2000; Webster et al., 2001). The

fumigant has been utilized since the 1950s in minor-use crops to eliminate pest problems

(Webster et al., 2001). There are a limited number of alternative pesticides registered in

minor use crops because of the high cost of registering new pesticides (Webster et al.,

2001). Methyl bromide is applied as soil fumigant and is immediately covered by plastic

mulch. Soil fumigation accounts for nearly 80% of the worldwide use of methyl bromide

(United Nations Environmental Programme, 1997). Tomatoes (35%) and strawberries

(20%) account for more than half of the methyl bromide used in the U.S. (VanSickle et

al., 2000). It is estimated that the loss of methyl bromide will have a $1 billion impact on

the U.S. winter vegetable industry, and Florida will account for the majority of this

impact (Spreen et al., 1995; VanSickle et al., 2000). Due to the phase out of methyl









bromide, the concentration applied in methyl bromide: chloropicrin mixtures has been

lowered from a 98:2 to 67:33. More than three-fourths of Florida growers cite the loss of

methyl bromide as their biggest concern for future pest management.

Chemical Alternatives for Methyl Bromide

Several chemicals are currently being tested for replacement of methyl bromide.

These include fumigants and herbicides such as 1,3-dichloropropene (1,3-D) chloropicrin

and napropamide. These have been studied in varying combinations and rates. No single

chemical by itself has proven to be a suitable alternative to this point. Gilreath et al.

(2004) indicate that there are several alternatives for methyl bromide in vegetable crops.

However, effectiveness of available alternatives can be affected by the nature of the crop

rotation and the planting season (Gilreath et al., 2004). There is no single molecule that

could replace methyl bromide due to inconsistency of fumigant efficacy (Gilreath et al.,

2004).

1,3-dichloropropene + chloropicrin (Telone C-35 and C-17)

There are many restrictions on the use of 1,3-dichloropropene in Florida and

additional use restrictions in certain Florida counties (Dow Agrosciences, 2003 a,b). 1,3-

D can only be applied in areas with a shallow hard pan or soil layer restrictive to

downward water movement (such as spodic horizon) within six feet of the ground surface

and that are capable of supporting seepage irrigation regardless of irrigation method

employed (Dow Agrosciences, 2003 b). These counties include: Collier, Dade,

Hillsborough, Indian River, Lake, Okeechobee, Palm Beach and Polk (Dow

Agrosciences, 2003 a,b). Field selection is important when using 1,3-D because it cannot

be applied within 100 feet of drinking water wells or occupied structures (Dow

Agrosciences, 2003 b). Personal protective equipment required during 1,3-D application









includes a full spray suit, rubber gloves, boots and full-face respirator for all personnel

present in the field during the in-row application. Due to these requirements, which are

uncomfortable under hot Florida conditions, research is being shifted toward a broadcast

application of Telone mixtures. Research has been conducted in strawberries using a

combination of Telone C-17 or C-35 + Devrinol as an in-row treatment. This

combination was compared to methyl bromide for weed, strawberry yield response

disease and nematode control (Noling and Gilreath, 2002). With some variability, the

response of the strawberry plants in both yield and growth to Telone C-17 or C-35 +

napropamide were nearly equivalent to that of methyl bromide (Noling and Gilreath,

2002). However, due to the additional costs previously mentioned, additional methods of

application still need to be identified for this to be a good alternative to methyl bromide.

Chloropicrin

Chloropicrin was first tested as a preplant soil fumigant in 1920 (Wilhelm, 1996).

Chloropicrin is very effective against soil-borne disease, some nematodes, and other pests

(Wilhelm, 1996). Therefore, to improve its spectrum of control it is combined with

compounds such as 1,3-dichloropropene for nematode control and compounds such

metam sodium, dazomet and pebulate for their herbicidal properties (Wilhelm, 1996).

However, pebulate is no longer available. Chloropicrin is a soil fumigant that is injected

into the soil approximately 15.2- 25.4 cm below the surface at least 14 days prior to

planting (Wilhelm, 1996). Chloropicrin is a tear-producing chemical, and protection

must be taken during application to avoid harmful exposure. Chloropicrin undergoes

rapid breakdown in sunlight and does not have significant ozone depleting potential. It is

metabolized in the soil to carbon dioxide (Wilhelm, 1996).









Herbicides

Few herbicides are registered for vegetable production making weed control

extremely difficult (Creamer and Baldwin, 2000). Pesticide registration is very

expensive, and vegetable crops are planted on a relatively small number of hectares,

further inhibiting registration for these minor use crops (Webster et al., 2001). Although

registered fumigants are available for use as methyl bromide alternatives there are limited

numbers of effective herbicide partners registered for use in vegetable crops (Schneider et

al., 2003). One alternative is napropamide (Devrinol), an amide herbicide compound that

is applied to the soil and must be incorporated within seven days of the application or

sprinkler irrigation. Napropamide can be applied up to 35 days prior to harvest or

preemergence in a tank mix in crops such as strawberries, tomatoes, and peppers (United

Phosphorus Inc. 2002). This is often applied with Telone to increase weed control. It

also has a residual period of 4-10 months. This combination can be used in both

strawberries and tomatoes, two of the most valuable crops grown in Florida. Tillam, a

preemergence herbicide that must be incorporated into the soil immediately has shown

promise as a partner to fumigants due to its ability to effectively control both yellow and

purple nutsedge later in the growing season (Gilreath et al., 1996). However, the

registration under Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) lapsed in

December 2002 and is no longer available (Osteen, 2003). Halosulfuron methyl (Sandea)

has shown promise as a preplant or postemergent herbicide for within row and row

middles for control of nutsedges, pigweeds and ragweed in asparagus, cucumbers,

cantoloupes and fruiting vegetables (Gowan Company, 2002).









Sustainable Agriculture

In addition to chemical alternatives, more sustainable nonchemical alternatives to

methyl bromide are also being investigated. Sustainable agriculture is profitable crop

production that builds soil resources and prevents environmental contamination.

Sustainability also involves social, economic, and ecological relationships at local,

national, and global levels (Abdul-Baki and Teasdale, 1997). The goal of sustainable

agriculture is to conserve, build and maintain the soil at a high level of fertility (Abdul-

Baki and Teasdale, 1997).

There is an increasing concern among producers, agricultural scientists and the

general public about reducing the environmental impacts of agriculture, and a growing

interest in maintaining or improving the quality of agricultural soils (Doran et al., 1994).

This has caused a shift towards practicing sustainable agriculture. Some of the reasons

for this are: contamination of the environment by agricultural chemicals, soil erosion,

depletion of natural resources and pesticide residues in food (Lu et al., 2000). Some of

the major practices being used in sustainable agriculture include crop rotations, reduced

tillage, use of animal manures, and cover crops (Lu et al., 2000).

The Weed Science Society of America supports the concept that sustainable

agriculture must include the profitable production of an abundant quantity of high

quality, reasonably priced food and other agricultural products while maintaining or

improving natural resources and having minimal adverse impact on the environment

(Creamer et al., 1996; Worsham, 1991). Since weeds are a major factor affecting

efficient agricultural production, employment of efficient, economical, and

environmentally safe weed management systems will be necessary to maintain a viable

sustainable agriculture (Creamer et al., 1996; Worsham, 1991). The absence of a suitable









chemical alternative to methyl bromide underscores the need for more sustainable

approaches to pest management in vegetable crops.

Crop and Weed Interference

Weed interference is the direct effects that weeds might impose upon other plants,

such as competition, allelopathy, parasitism, and indirect effects not referring to any one

particular effect. Crop interference may be described as crop effects on weeds that reduce

weed emergence, biomass, and yield. In many cropping systems, crop interference with

weed growth and reproduction is a fundamental method of weed control (Jordan, 1993).

The interest in weed control through crop interference has been revived due to the need to

reduce environmental and economic costs of crop production. Crop interference should

occur as early as possible in growth to prevent resource consumption by weeds (Jordan,

1993). Crops interfere with weed growth and vice versa (Jordan, 1993). Crop

interference can be an important component of integrated weed management systems.

Cover Crops

Cover crops are becoming an important component of sustainable agriculture.

Cover crops have the potential to be an alternative weed control method for both

conventional and organic farmers. Organic farmers do not use synthetic herbicides or

fertilizers for crop production and utilize alternative means to manage weeds and fertilize

crops. Using leguminous cover crops as green manure can replenish the soil of essential

nitrogen (N) at the end of the growing season. The principal goal of using cover crops

for weed control is to replace an unmanageable weed population with a manageable

cover crop (Teasdale, 1996).









This is accomplished by

"adjusting the phenology of the cover crop to preempt the niche occupied by weed

populations"

(Teasdale, 1996).

Cover crops play an important part in sustainable agriculture by preserving

productivity of soil resources and maintaining environmental quality. While cover crops

are not usually planted for profit or economic value, they can have environmental value

directly with respect to maintaining improved soil quality and indirectly through

reduction in pesticide use. However, the success of cover crops depends on a balance of

positive and negative cover crop influences (Teasdale, 1996). One of the most important

factors affecting the cover crops profitability is their ability to enhance crop yields (Lu et

al., 2000). Studies on fresh market tomato production have shown that tomatoes grown

with hairy vetch mulch were higher yielding and more profitable than those grown with

no mulch or black polyethylene mulch (Lu et al., 2000). According to Teasdale (1996)

and Lu et al. (2000) some of the common advantages of growing cover crops are nutrient

enhancement (particularly when using a legume cover crop prior to a grain crop), soil

nutrient capture, soil moisture retention, long-term soil stabilization, improve soil organic

content, control pests, reduce weed competition, reduce the need for herbicides, provide

suitable habitat for beneficial predator insects, and act as non-host crops for nematodes

and other pests in crop rotations. Through the use of cover crops and crop management

systems weed populations and crop yield can be affected by cover crops and management

systems in both the long and short term (Ngouajio et al., 2003).

Growing cover crops also has disadvantages including additional management and

expense, interference with crop establishment, soil moisture depletion, cooler soil









temperatures, and less predictable crop fertilizer requirements (Teasdale, 1996). A major

concern of using cover crops in cooler climates is that soil will be cooled to a point in

which crop production is delayed (Abdul-Baki et al., 1996; Hutchinson and McGiffen,

2000; Masiunas et al., 1995). Therefore, the use of cover crops can be a disadvantage

when the soil must be warmed quickly after a cold winter (Hutchinson and McGiffen,

2000; Knavel and Herron, 1986; Masiunas et al., 1995). Another consequence of

growing cover crops is that they use soil water causing a positive, neutral, or negative

effect on the soil water supply for the next crop. Negative effects may occur when cover

crops use excess water in areas with limited amounts of rainfall. In general, cover crops

deplete water when growing and conserve water when they are killed, if the residue

remains on the soil (Unger and Vigil, 1998).

Allelopathy

Cover crops are also grown for their allelopathic properties. Allelopathy refers to

any direct or indirect harmful effect produced in one plant through toxic chemicals

released into the environment (Rice, 1974). This definition has been broadened to

include chemicals produced by actinomycetes, algae, fungi, or other microbes that may

associate with the plants in the rhizosphere (Weston, 1996). Many cover crops release

significant levels of allelochemicals that reduce weed emergence (Barnes and Putnam,

1983, Masiunas et al., 1995, Putnam et al., 1983). Allelopathy is often inferred from the

response of a target plant to the presence of extracts, leachates, or ground plant tissue.

The effectiveness of allelopathy depends on a chemical compound being added to the

environment, whereas competition is the removal or reduction of some factor from the

environment required by other plants or microorganisms sharing the habitat (Birkett et

al., 2001). Chemicals with allelopathic potential are present in virtually all plants and in









most tissues, including leaves, stems, flowers, roots, seeds, and buds (Caamal-Maldonado

et al., 2001). Under appropriate conditions, these chemicals may be released into the

environment in sufficient quantities to affect neighboring plants (Caamal-Maldonado et

al., 2001). Scientists agree that allelopathy is a component of plant interference, but they

do not agree on the relative importance of its contribution to plant growth and community

structure (Hoffman et al., 1996).

One common way that allelopathy may be utilized in weed management systems is

through the manipulation of allelopathic cover crop residues in annual and perennial

cropping systems (Caamal-Maldonado et al., 2001). The effects of microbial

enhancement on cover crop decomposition or release of allelochemicals is unknown, but

may contribute to a rapid release of water-soluble inhibitors (Caamal-Maldonado et al.,

2001).

Annual legume residue has also been shown to release allelochemicals that

suppress germination and growth of selected species (Caamal-Maldonado et al., 2001).

However, little is known about the influence of legume cover crops on weed populations

in the field (Teasdale et al., 1991).

Cover Crop Species

Sunn hemp (Crotalariajuncea L.), velvetbean (Mucunadeeringiana (Bort) Merr)

and cowpea (Vigna unguiculata L.) are three leguminous summer cover crops that have

the potential for inclusion in vegetable production rotations (Creamer and Baldwin,

2000). Further evaluation is needed to use these three cover crops as candidates as

biological alternatives for methyl bromide in south Florida (Wang et al., 2003).









Sunn Hemp-Crotalariajuncea L.

Sunn hemp is a tropical legume that may be adapted to residue management

systems. It has already been used extensively for soil improvement or green manuring in

the tropics (Lales and Mabbayad, 1983). Sunn hemp is non-toxic and can be used as

forage as well as green manure. Although sunn hemp is not winter hardy, it may be able

to produce sufficient biomass during the fall (until frost) to provide groundcover and N to

a following summer cash crop in southern temperate regions (Zulfadi et al., 1997). Sunn

hemp is a superior cover crop with good germination rates and produces a thick ground

cover rapidly (Li et al., 2000; Li et al., 1999). In south Florida, sunn hemp can grow 183-

356 cm tall in a period of 12 weeks (Li et al., 2000). Other cover crops are not known to

grow as quickly (Li et al., 2000). In addition to excellent biomass yields, subsequent

cash crop yields with a prior sunn hemp cover crop have been promising. Li et al. (1999)

concluded that sunn hemp is better than currently used cover crops in south Florida.

Work done by Mansoer et al. (1997) showed that sunn hemp produced large quantities of

dry matter during the fall season and covered the soil surface rapidly, protecting it from

erosion. Li et al. (1999) found that sunn hemp fixed and retained up to 248 lb N/ac.

Sunn hemp is of interest as a cover crop because it is also suppresses plant parasitic

nematodes (McSorley, 1998, 1999; McSorley and Dickson, 1989, 1995; Wang et al.,

2002), which makes it a useful addition to a nematode susceptible crop rotation (Li et al.,

2000). Tomatoes produced significantly higher early yield and total extra large fruit and

total marketable yield when grown in sunn hemp plots compared to those grown in

sesbania treatments and the control (Li et al., 1999). The high biomass and nitrogen

fixation by sunn hemp may be the major factor of the higher yields (Li et al., 1999).









Velvetbean-Mucuna deeringiana (Bort) Merr

Velvetbean grows fast and produces abundant biomass. Research done by Caamal-

Maldonado et al. (2001) suggested that velvetbean was very effective for weed

suppression. Their research also evaluated phytotoxic effects and they found that

velvetbean affected the growth of weeds more than the germination. Caamal-Maldonado

et al. (2001) found that velvetbean would be useful in tomato crops because the

phytotoxic effects only affect the weed population and cause no damage to transplanted

tomato plants, although direct seeded tomato plants were affected. Many plants possess

phytotoxic properties; however, the actual chemical has not been isolated and this

allelopathy remains unproven. The main allelopathic agent of velvetbean is known to be

L-3,4-dihydrophenylalanine (L-DOPA). Various unusual aminoacids have also been

found in velvetbean as well as other leguminous cover crop species (Caamal-Maldonado

et al., 2001; Fujii, 1999).

Velvetbean also suppresses plant parasitic nematodes (McSorley, 1998, 1999;

McSorley and Dickson, 1989, 1995, Wang et al., 2002). Research done by Brunson et al.

(1994) indicated that plots planted with velvetbean after final harvest and disked in 90

days later had substantially lower numbers of nematodes whereas most conventional

plots showed an increase. Wang et al. (2003) found that the nematode suppressive effects

of velvetbean persisted long enough to avoid significant yield loss when planted in

rotation with highly nematode-susceptible soybean.

Velvetbean is also an important contributor of organic matter to the soil.

Velvetbean is very effective in fixing and recycling N, preventing significant nutrient

losses to the environment practically eliminating the need for external fertilizer without

compromising yield (Buckles et al., 1998; Capo-chichi et al., 2002). Velvetbean









competes well with weeds because of its rapid and extensive growth. Caamal-

Maldonado et al. (2001) showed that velvetbean was the most effective of four legume

species (jackbean, jumbie bean, wild tamarind) at suppressing weeds. The canopy of

velvetbean when completely developed significantly decreases the amount of light that

reaches the soil. Wang et al. (2002) found no significant difference in tomato plots

planted with velvetbean compared with plots that were fallow or planted with sunn hemp

or sorghum sudangrass. However, the biomass of tomatoes grown in velvetbean plants

were significantly less than with the other cover crop treatments.

Cowpea-Vigna unguiculata L.

Cowpea is a warm season plant that is well adapted to heat and drought conditions.

According to research performed by Creamer and Baldwin (2000) cowpea was shown to

be very vigorously competitive with weeds, and produced large amounts of biomass and

N. Mulch from a prior cowpea cover crop has been shown to reduce the weed

populations significantly in pepper at three, five, and nine weeks after transplanting.

(Hutchinson and McGiffen, 2000). Ngouajio et al. (2003) found that using cowpea as a

mulch in lettuce production resulted in a smaller weed infestation than sudangrass cover

crop that was incorporated prior to planting the lettuce. Cowpea also produced the

highest lettuce yield when incorporated into the soil prior to transplanting partially due to

the amount of N fixed by the cowpea (Ngouajio et al., 2003). However, an increase in

populations of perennial weeds such as bermudagrass and yellow nutsedge occurred in

the cowpea plots over time and could cause serious constraints if their populations build

over several seasons. Wang et al. (2002) found that tomato yields with a prior cowpea

cover crop were lower than those of the fallow plots; however, tomato biomass was









greater than with the other cover crop treatments. They believe that this could be due to

chemical characteristics in the cowpea residues or the Carbon/Nitrogen ratio.

Like sunn hemp and velvetbean, some cowpea cultivars have been shown to

suppress plant parasitic nematodes (McSorley, 1998, 1999; McSorley and Dickson, 1989

1995; Wang et al., 2002).

Weed Control

Weed control is essential for maximum crop yields and high quality produce.

Weed control can be serious limitation to vegetable production and is the principal reason

for farmers not converting to organic agriculture (Davies et al., 1997; Walz, 2002). Weed

control and crop yield were improved and more consistent when cover crops were

supplemented with herbicides in various reduced tillage systems (Teasdale, 1996).

Reducing the use of preemergence herbicides could reduce environmental impact since

these are more frequently detected in ground and surface waters than postemergence

herbicides (National Research Council, 1989, Teasdale, 1996). Postemergence

herbicides are generally used at lower rates, are less persistent and could eventually

replace preemergence herbicides (Teasdale, 1996). Some weed management practices

that are being emphasized are cultural practices, use of herbicides at minimal rates to

control specific weeds, mechanical cultivation, and field scouting techniques to determine

the need and choice of herbicides, to maintain a profitable yield while protecting the

environment and natural resources for future generations (Creamer et al., 1996).

Killing Cover Crops

In the southeast, it appears that the most practical method for killing cover crops is

to use a nonselective herbicide followed by a selective postemergence herbicide as

needed, especially for grasses and weeds (Worsham, 1991). Using this approach will









enhance the sustainability of agriculture for the following reasons: a) conservation of soil,

b) the use of herbicides (especially preemergence herbicides) should be reduced, c)

herbicides used for killing cover crops have little to no potential for contaminating

groundwater, and d) postemergence selective herbicides have little potential for

environmental contamination (Worsham, 1991).

An alternative method is to mechanically kill the cover crops. Mechanical methods

include mowing, rolling, roll-chopping, undercutting and partially rototilling (Creamer

and Dabney, 2002). The success of these types of management strategies depend

partially on the growth stage and species of the cover crops (Creamer and Dabney, 2002).

The method of killing cover crops can affect weed emergence. Crop residue left intact on

the soil surface by undercutting or sickle bar mowing of the cover crops yielded fewer

weeds than the finely chopped residue that results with a flail mower (Creamer and

Dabney, 2002, Creamer et al., 1995). Creamer and Dabney, (2002) found that mowing in

the vegetative state was more effective method at killing cowpea than undercutting and

rolling. These methods killed 98%, 85%, 5 %, respectively. These methods were even

more effective on velvetbean resulting in 100%, 95%, 52% of the velvetbean killed with

mowing, undercutting, and rolling, respectively (Creamer and Dabney, 2002).

Competition

Competition results from a loss in crop yield or quality from interactions among

crops and weeds (Radosevich, 1987). Competition continues to be the most widely

debated issues in ecology. There are several methods to study competition including:

replacement series experiments or substitutive experiments, additive experiments,

systemic methods, addition series experiments and neighborhood experiments









(Radosevich, 1987). The replacement series and additive approach were used to study

competition between cover crops and yellow nutsedge and smooth amaranth.

Additive Experiments

Additive experiments are commonly used by weed scientists and are more

adaptable to field conditions than greenhouse conditions. Additive studies can be

performed using two or more plant species, however they are usually performed using

only two species a crop and a weed (Radosevich, 1987). In this design, the density of one

species is held constant while the density of another species is varied (Cousens, 1991,

Radosevich, 1987). In general, the crop density is held constant and the weed density is

varied. However, in the present study, experiments were performed with the weed

population at a constant density and varying the crop density. The additive approach has

been criticized for not adequately taking into account the influence of total density and

species proportion on the outcome of competition (Harper, 1977; Radosevich et al.,

1997). In addition, the total plant density varies among treatments and, therefore the

proportion among species changes simultaneously with total plant proportion

(Radosevich et al., 1997). Because both density and proportion vary, it is difficult to

interpret the effects of either factor alone (Radosevich et al., 1997). The additive

approach is appropriate for this study because it allows the examination of a range of

cover crop densities to determine an optimum density for weed suppression.

Replacement Series Experiments

The substitutive approach is more commonly used by ecologists and is often used

in greenhouse experiments. The replacement series measures competition between two

plant species by varying proportions of each species while maintaining a constant total

density. Monocultures of each species are also included in replacement series









experiments (Cousens, 1991; Jollife, 2000; Radosevich, 1987). Replacement series

experiments have been used extensively in both agricultural (Santos et al., 1997; Jolliffe

et al., 1984; Meekins and McCarthy; 1999) and ecological experiments (Roush et al.;

1989; Roush and Radosevich, 1985; Snyder et al., 1994). This design is used for two

main reasons: 1) to determine the better competitor of two species or biotypes, and 2)

evaluate the nature of the interaction between two species or biotypes (Cousens, 1991).

Replacement series experiments allow comparison of the yield of the mixtures of species

with the yield of each species grown in monoculture (Jollife,2000; Radosevich, 1987).

There are both advantages and disadvantages of using the substitutive approach.

The advantages include: the total plant density being held constant so that only one

variable (proportion) changes, predictiveness, and the ability to predict shifts in species

composition (Radosevich et al., 1997). Predictiveness (the ability to predict competition)

is the main advantage of this type of approach (Radosevich et al., 1997). Replacement

series experiments are often criticized because most crops are planted using a constant

density rather than variable, making it artificial for field implementation (Radosevich et

al., 1997). Replacement series experiments are limited because actual and expected

monoculture yields and the outcome of the experiment may vary according to the plant

density chosen in the experiment (Radosevich et al., 1997). Also, they cannot be used to

separate the effects of inter- and intra- specific competition (Cousens, 1991) and it is

impossible to distinguish between no competition and both species are equally

competitive.

Relative yield is a valuable calculation that can be obtained from replacement series

experiments. Relative yield (RY) and relative yield total (RYT) can be obtained from dry









weights of the individual species and indicates the competitiveness of the individual

species (Meekins and McCarthy, 1999) and how the species are using resources in

relation to one another (Radosevich et al., 1997). Relative yield values are calculated to

compensate for absolute differences in biomass between species and to look at

interspecies comparisons (Meekins and McCarthy, 1999). Relative yield can be obtained

by using equations 1 and 2 and relative yield total can be derived using equation 3

(Fowler, 1982; McGilchrist and Trenbath, 1971; Meekins and McCarthy, 1999).

Eqn (1) RY yield species of A in mixture
species A yield of species A in monoculture

yield species of B in mixture
Eqn (2) RY =
species B yield of species B in monoculture

Eqn (3) RYT = RYp.c. A + RYspecie. B

An RYT value of less than one indicates mutual antagonism between the two species.

RYT greater than one indicates symbiosis between the two species and no competition

between them. When RYT=1 the two species are competing for the same resource

(Meekins and McCarthy, 1999).

Objectives and Hypotheses

The cover crops sunn hemp, velvetbean, and cowpea (cv. Iron Clay) because of

their nematode suppressive ability are being evaluated for use in summer fallows as a

methyl bromide alternative. The overall objective of our study was to evaluate whether

these cover crops can also be utilized to suppress weeds.

Specific objectives of greenhouse replacement series experiments were to

determine the competitive ability of the three individual cover crops when grown in

combination with the two model weed species Cyperus esculentus L. (yellow nutsedge)









and Amaranthus hybridus L. (smooth amaranth). The nutsedge experiment also had an

additional objective to determine if the cover crop species would have an effect on the

number of tubers produced by the nutsedge. The hypothesis is that the cover crop species

will be more competitive than the two weed species and varying growth habits of the

cover crop species will have an effect on the weed species. In addition, it is hypothesized

that when yellow nutsedge is grown in a high density of cover crop that tuber production

will decrease.

The specific objectives of additive field experiments were (1) to determine the

optimum planting densities of the three leguminous cover crops for suppression of

smooth amaranth, (2) to determine the amount of canopy cover produced by the cover

crops, (3) to assess cover crop productivity in terms of biomass over the period of the

experiment. It was hypothesized that as cover crop density is increased there would be a

concomitant decrease in weed biomass until an optimum cover crop density is achieved

beyond which no further decrease in weed biomass can be obtained.














CHAPTER 2
MATERIALS AND METHODS

Replacement Series or Greenhouse Experiments

Preliminary Greenhouse Experiment-Yellow Nutsedge

Replacement series experiments were performed during the spring of 2002 in

Gainesville, Florida in a greenhouse using combinations of three leguminous cover crop

species and yellow nutsedge (Cyperus esculentus L.). Each cover crop species was

planted as an individual experiment in a randomized complete block design with four

replications. Cover crop species were cowpea (Vigna unguiculata L.) cv. Iron Clay

(Wise Seed Company, Frostproof, FL), and sunn hemp (Crotalariajuncea L.) cv. Tropic

Sun (Wise Seed company, Frostproof, FL). Due to germination problems, velvetbean

(Mucuna deeringiana L.) was not included in this experiment. The cover crop and weed

species were planted in five combinations of crop:weed. The proportions used were

100:0, 75:25, 50:50, 25:75, and 0:100. A total plant density of 16 plants was planted in

16x37 cm planter boxes filled with seedling- pre-moistened peat lite mix for tobacco

potting soil. Prior to planting imbibed yellow nutsedge tubers were exposed to a heat

treatment of 35 C for 1 hour to stimulate sprouting. The cover crop seeds and nutsedge

tubers were then planted in the planting pattern (Figure 2-1). The plants were allowed to

grow together for 8 weeks.

One day prior to harvest, plant heights were measured from the soil surface to the

shoot apices of the cover crops. Yellow nutsedge heights were measured from the soil

surface to the point at which the blades started to bend over. Photosynthetically active









radiation (PAR) was measured using a LI-COR LI-170 Quantum Radiometer/Photometer

(LI-COR Inc., Lincoln, Nebraska). These measurements were taken for cowpea both

above the canopy and again at the soil surface below the canopy. For sunn hemp PAR

was also measured at the middle of the canopy. Measurements were used to derive the

percentage of PAR penetrating the canopy. Plants were harvested by block beginning

with the sunn hemp treatments over a three day period. Crop and weed above ground

biomass were taken separately from each individual box. Leaf area of each species was

determined using a LI-COR LI-3100 area meter (LI-COR Inc. Lincoln, Nebraska).

Leaves and stems of cover crops and yellow nutsedge were placed in separate paper bags

and dried at 72C for 3 days. After drying, tissue was allowed to cool to room

temperature and then weighed. Tuber production was also determined at the end of the

experiment. Tubers were washed free of soil and tuber number and dry biomass were

obtained.


Figure 2-1. Greenhouse replacement series planting pattern for all experiments.









Greenhouse Experiments-Yellow Nutsedge

Replacement series experiments were performed during fall 2002 and spring 2003

in Gainesville, FL using combinations of three cover crop species and yellow nutsedge.

These experiments were conducted as described for the preliminary experiment except

for the following changes. The velvetbean cultivar was changed to 'Georgia Bush'

(Sharad Phatak, Tifton, Georgia). The seeds of all cover crop species were treated with

cowpea inoculant, which is the appropriate rhizobium inoculant for these species (Urbana

Laboratories, St Joseph, MO). The planting medium used consisted of 50% vermiculite,

30% sphagnum peat moss, 20% perlite with wetting agents and starter nutrients (Alachua

Farm and Lumber Center, Alachua, FL).

Greenhouse Experiments-Smooth Amaranth

Replacement series experiments were performed using smooth amaranth

(Amaranthus hybridus L.)as the weed species during the spring and summer 2003 in

Gainesville, FL. Smooth amaranth experiments were performed in a similar manner as

yellow nutsedge experiments except for the following changes. Two weeks prior to

planting the cover crops, smooth amaranth seeds were germinated in 10.2 cm pots and

then transplanted into 2.5 x 2.5 cm cell seedling trays. Cover crop seeds were planted in

the planter boxes in the illustrated planting pattern (Figure 2-1). When the cover crops

emerged and were approximately the same height as the amaranth, the amaranth was

transplanted into the planter boxes with the cover crop.

Preliminary Field Experiment

A preliminary field experiment was performed at the North Florida Research and

Education Center (NFREC) in Live Oak, FL on Lakeland fine sand soil during the

summer of 2002. An additive study was conducted using varying densities of the three









cover crop species and a constant density of smooth amaranth. To reduce the likelihood

of infestation by other weeds, two weeks prior to harvest, the field was fumigated with a

67:33 ratio of methyl bromide: chloropicrin at a rate of 448 kg/ha. The experimental

design was a split plot with cover crops assigned to the main plots in a randomized

complete block design with four replications. Cover crop densities were randomly

assigned to subplots, which were 1 m x 8 m in size. Planting was done using a Planet Jr

push planter and rhizobium (Urbana Laboratories, St Joseph, Missouri) was applied to the

seed just prior to planting according to package directions. Cowpea cv. Iron and Clay

(Wise Seed Company, Frostproof, Florida) was planted at 38, 75, 113, 150, 188

plants/m2. Sunn hemp cv. Tropic Sun (Wise Seed Company, Frostproof, Florida) was

planted at 44, 88, 132, 176, 220 plants/m2, and due to germination problems sections of

the subplots were replanted one week after initial planting to increase plant stand.

Velvetbean (Adams-Briscoe Seed Co., Jackson, Georgia) was planted at 15, 29, 44, 58,

73 plants/m2. Within each plot, the row spacing varied depending on the desired density

of cover crops (Figure 2-2) with the lowest densities obtained with one row and the

highest densities at 5 rows. However, the spacing within the row remained the same for

each cover crop.

The The smooth amaranth was seeded in trays at 5-10 seeds per cell and

subsequently thinned to one seedling per cell. The smooth amaranth was planted three

weeks prior to transplanting. At cover crop emergence, about 3 days after planting,

smooth amaranth was transplanted into the field in a designated pattern (Figure 2-3)

within the plots at a constant density of five plants/M2 and watered in by overhead









irrigation. The experiment was carried out for a 10-week period and the plots were

maintained free of other weed species.

Two days prior to biomass harvest, PAR was measured 30.5 cm above the soil

surface with a LI-COR 1-m line quantum light sensor (LI-COR Inc., Lincoln, Nebraska

68504). Cover crop heights were measured on the day of harvest from the soil surface to

the apex of the stem. The heights were taken at four random points within each plot and

averaged to obtain a mean plant height for each plot. The plots were harvested by using a

quadrat to randomly select a one m2 area of the plot. The shoots of the crops and weeds

were harvested by cutting at soil level and placed in separate bags. The harvested

material from each plot was dried and the dry biomass was obtained. After obtaining the

biomass samples, the rest of the plot was cut down and the cover crop residue was

retained in the plot as a mulch. At two-week intervals for four weeks, regrowth of cover

crops and weed was evaluated. The plots were rated visually for both crop and weed

regrowth.

Density 1- One row of cover crop centered within the plot.
X
50
Density 2- Two rows of cover crop spaced 50cm apart within the plot.
X X
25 75
Density 3- Three rows of cover crops spaced 33.3cm apart within the plot.
X X X
16.65 50 83.3
Density 4- Four rows of cover crops spaced 25cm apart within the plot.
X X X X
12.5 37.5 62.5 87.5
Density 5- Five rows of cover crops spaced 20cm apart within the plot.
X X X X X
10 30 50 70 90
Density 6- 100% smooth amaranth planted according to planting pattern.

Figure 2-2. Planting pattern for cover crop densities: 2002 and 2003.











IEI--][]









Figure 2-3. Smooth amaranth planting pattern for additive experiments summer 2002.

Field Experiments 2003

Additive field studies were performed at the Plant Science Research and Education

Unit (PSREU) in Citra and (NFREC) in Live Oak, summer 2003 using varying densities

of the three cover crop species and a constant density of smooth amaranth. Soil type at

Citra is a Sparr sand while the soil type at Live Oak is a Lakeland fine sand. These

experiments were conducted as described in the preliminary field experiment except for

the following changes. Instead of fumigation, a stale seedbed approach using glyphosate

was used prior to planting the experiment to reduce infestation of other weeds. The

subplots were 1 m x 7 m and cover crop density varied by species. Seeds of the three

cover crop species were weighed out as follows: cowpea and sunn hemp- 1.42 kg and

velvetbean- 2.7 kg. Cowpea rhizobium inoculant (Urbana Laboratories, St Joseph, MO)

was applied to the seeds one day prior to planting to cowpea and sunn hemp at a rate of

0.64 g mixed with 6 ml of water and to velvetbean cv. Georgia Bush at a rate of 0.96 g

inoculant mixed with 10 ml of water. Inoculant was then applied to the seed and allowed

to dry on the seed. Cover crop seeds were planted in Citra on June 30 and smooth

amaranth seedlings on July 2: at Live Oak cover crops were planted July 14, with

amaranth transplanted on July 15. All cover crops were planted according to the planting









pattern in Figure 2-2. Cowpea cv. Iron Clay was planted and thinned to 10, 20, 30, 40, 50

plants/m2. Sunn hemp cv. Tropic Sun was planted at 20, 40, 60, 80, 100 plants/m2.

Velvetbean cv. Georgia Bush was planted at 10, 20, 30, 40, 50 plants/m2. It was not

necessary to thin sunn hemp or velvetbean, as populations were attained by the seeding

plate used in planting. Smooth amaranth seeds were aerated with an aquarium aerator for

72 hours to imbibe the seeds and break dormancy. Seeds were then scattered in planter

boxes to germinate. When the smooth amaranth seedlings were at the two-leaf stage,

they were transplanted to 2.5 x 2.5 cm cells in plastic seedling trays. Smooth amaranth

was planted in a designated pattern (Figure 2-4) within the plots at a constant density of

15 plants/m2. At time of cover crop emergence about 3 days after planting, smooth

amaranth was transplanted into the field and watered in by overhead irrigation. The

experiment was carried out for a 12-week period and the plots were maintained free of

other weed species at Citra. However, an infestation of hairy indigo occurred within the

plots in Live Oak and was harvested in addition to the smooth amaranth to determine

interference between the cover crops and smooth amaranth occurred due to the presence

of this weed.

PAR was measured with a LI-COR quantum light sensor (LI-COR Inc., Lincoln,

Nebraska), plant height and plant canopy measurements were taken at three, six, nine,

and 12 weeks after planting. Heights for both the cover crops and the smooth amaranth

were taken at four random points within each plot and averaged to obtain mean plant

height for each species. Plant canopy width in two directions was taken from one random

plant in each plot. Biomass samples were harvested by randomly selecting a 1m2 area of

plot at six and 12 weeks after planting. The experiment at Citra was harvested on











September 16, with Live Oak harvested October 9. After the 12-week biomass sampling,


the remainder of the plot was cut down using a tractor-mounted drum mower at Citra and


a walk behind sickle bar mower at Live Oak and the residue left in the plot as a mulch.


At two and four weeks after harvest plots were visually rated for weed and crop regrowth.


At the end of the 4-week period, a 0.5m2 sample was taken to determine if there was


continued weed suppression of other species when the cover crops were left as mulch in


the field.


8.75cm


16.5cm


10cm


20cm


- I I I I -


Figure 2-4. Planting pattern of smooth amaranth in additive experiments, summer 2003.


-! P P P -


L



F
LI I I



F-I F-1



F-I M









Statistical Analysis

Greenhouse Data

Analysis of variance (ANOVA) was performed using the PROC GLM procedure of SAS1

for all parameters to determine significance at the (a < 0.05) level. If there was no

interaction due to season data were combined. LSMEANS were obtained. Regression

was then performed on the means when a significant response occurred due to proportion.

Data obtained from the biomass of both the crop and weed species were converted to

relative yield (RY) to determine how well the species perform in mixture as compared to

the monoculture (Equations 2.1, 2.2). Relative yield total was also calculated to

determine how each species contributed to the total yield in mixture (Equation 2.3).

Percentage of PAR penetrating the canopy were calculated by dividing PAR below

canopy by PAR at the top of the canopy. The leaf areas obtained were used to calculate

leaf area index (LAI) as indicated in Equation 2.4.

Eqn (2.1) RY yield species of A in mixture
Eqn(2.1) RY =
species A yield of species A in monoculture

qn (22) RY yield species of B in mixture
species B yield of species B in monoculture

Eqn(2.3) RYT = RYsp A+ RYspec.e. B

Tota leaf area
Eqn(2.4) LAI =
Surface area box


Field Data

Analysis of variance was performed using the PROC MIXED procedure of SAS to

determine significance (a < 0.05) of main effects and interactions. The three cover crops

1 SAS Software, Statistical Analysis Systems, SAS Campus Drive, Cary, NC 27511






29


species were analyzed separately due to differences in planting density. Means were then

obtained using LSMEANS option in SAS and were subjected to the Proc REG procedure

of SAS to determine the response to the effect of density or time. Plant heights were

taken at four random points with in the plots and a mean height was obtained for each

species in the plots. PAR was expressed as a percentage of the ambient light. Biomass

was also compared at 20 and 40 plants/m2, densities common to all three species.














CHAPTER 3
RESULTS AND DISCUSSION

Replacement Series Experiments

Replacement series experiments were conducted with three legume cover crops and

two model weed species yellow nutsedge and smooth amaranth to assess the competitive

ability of the cover crops and thus evaluating whether their potential for inhibiting weeds

during fallow periods may be due to a highly competitive nature.

Yellow Nutsedge and Cowpea

Studies with yellow nutsedge and cowpea were conducted in fall 2002 and spring

2003. There was no significant interaction between proportion and season for all

variables, except for total crop leaf area, crop LAI, combined leaf area, and dry weight of

tubers. The effect of season on each variable is shown in Table 3.1. When treatment was

significant, data was also subjected to regression, using the Proc Reg procedure of SAS.

Table 3-1. Variables of main effects differences due to season Fall 2002 and Spring 2003.
Variable Fall Spring Significance
Crop height cm 55.4 42.9 **
Weed height cm 59.7 34.1 ***
PAR top of canopy imol m-2S-2 289 828 **
PAR soil surface % 23.2 15.6 *
Tuber number 90.8 251 ***
Tubers per plant 8.9 24.5 ***
Dry weight tubers per plant g 0.53 2.4 ***
Crop leaf area/plant cm2 404 2159 ***
LAI weed 2.7 2.5 NS
Weed leaf area/plant cm2 607 596 NS
RY crop 0.59 0.81 **
RY weed 0.59 0.76 NS
RYT 0.94 1.3 *









Plant Heights

Plant heights were taken prior to harvest to assess the effect of the cover crop on

the growth of the weed as proportion of crop increased in the mixture. Cowpea and

yellow nutsedge heights were significantly higher in fall then spring (Table 3.1).

Although the height of cowpea was not significantly affected by the proportion of crop,

yellow nutsedge height decreased linearly as proportion of cowpea increased (Table 3.2).

Decline in nutsedge height indicates that high proportion of cowpea negatively affects the

growth of yellow nutsedge.

Table 3-2. Cowpea and yellow nutsedge heights in monoculture and mixture taken at 8
weeks after planting.
% crop Crop % Weed Weed
cm cm
100 53.3 0
75 48.6 25 35.8
50 48.3 50 43.9
25 46.4 75 48.4
0 100 59.6
Significance NS Significance p < 0.05
Slope Slope 0.30
Intercept Intercept 27.95
R2 R2 0.96

PAR

PAR measurements were taken below the canopy prior to harvest to determine if

the cover crop would decrease the radiation levels reaching the soil surface and thus

inhibit the growth of the weed. PAR reaching the soil surface was significantly lower in

the spring then fall (Table 3-1). However, PAR reaching the soil surface was not

significantly different due to proportion of cowpea in the mixture (Table 3-3).









Table 3-3 PAR measurements taken at soil surface 8 weeks after planting in monoculture
and mixture of cowpea and yellow nutsedge.
% Crop % PAR Soil Surface
100 19.1
75 21.8
50 22.2
25 19.2
0 14.8
Significance NS

Leaf Area and LAI

Leaf area was taken to determine how the proportion of cover crop: weed affects

the canopy growth of each species and thus the potential for light interception. Leaf area

was also used to derive leaf area index (LAI). There was a significant interaction

between proportion and season for crop LAI, therefore results are separated by season.

Crop LAI decreased linearly during both seasons as the proportion of crop decreased in

mixture (Table 3-4). LAI of yellow nutsedge had a linear increase as the proportion of

nutsedge increased in mixture. Leaf area per plant did not change with proportion for

either species, (Table 3-5). There was a significant interaction between season and

proportion for total leaf area of cowpea, therefore, means are separated by season. Total

leaf area of yellow nutsedge averaged over season increased linearly with an increase in

proportion of the weed in mixture (Table 3-6). Combined leaf area (total leaf area of

both spp. together) had a linear increase in both seasons (Table 3-7). During the fall

season there was an increase as proportion of nutsedge increased in mixture with

combined leaf area lower in both the crop and weed monoculture. However, in the spring

there was a significant decrease in leaf area as the proportion of cowpea decreased in

mixture, with crop monoculture producing the largest leaf area.









Table 3-4. Leaf area index of cowpea and yellow nutsedge in monoculture and mixture 8
weeks after planting.
% Crop LAI Crop % Weed LAI Weed
Fall Spring
100 3.1 13.9 0
75 2.3 10.5 25 1.1
50 1.3 8.4 50 2.4
25 0.8 4.4 75 3.2
0 100 3.7
Significance p < 0.05 p < 0.05 Significance p < 0.05
Slope 0.03 0.1 Slope 0.03
Intercept -0.1 1.65 Intercept 0.45
R2 0.97 0.98 R2 0.93

Table 3-5. Leaf area per plant of cowpea and yellow nutsedge.
% Crop Crop % Weed Weed
cm2 cm2
100 1175 0
75 1181 25 637
50 1336 50 668
25 1434 75 592
0 100 509
Significance NS Significance NS

Table 3-6. Total leaf area of cowpea and yellow nutsedge.
% Crop Crop % Weed Weed
Fall Spring
cm2 cm2
100 6800 30794 0
75 5007 23334 25 2549
50 2071 18605 50 5346
25 1710 9758 75 7098
0 100 8149
Significance p < 0.05 p < 0.05 Significance p < 0.05
Slope 72.83 271.35 Slope 74.2
Intercept -654.75 3663.55 Intercept 1148
R2 0.89 0.98 R2 0.93









Table 3-7. Combined leaf area: cowpea and yellow nutsedge Fall 2002 and Spring 2003.
% Crop Combined Leaf Area
Fall Spring
cm2
100 6800 30794
75 7335 26105
50 7639 23729
25 9068 16597
0 8580 7719
Significance p < 0.05 p < 0.05
Slope -21.2 222.6
Intercept 8942.8 9857.1
R2 0.75 0.93

Tuber Production

The number of tubers produced by each mixture was counted and the dry weights

were taken to determine if increasing the proportion of cowpea in the mixture would

negatively affect the number and size of tubers produced. There was a linear increase in

the number of tubers produced as proportion of nutsedge increased in mixture (Table

3-8). However, there was no significant difference in the number of tubers produced per

plant. The effect of species proportion on dry weight varied with season (p < 0.05).

Tuber dry weight was much larger in the spring than in the fall (Table 3-1). A significant

linear increase in tuber dry weight was observed in spring 2003. Tuber dry weight was

significantly higher in monoculture than in mixture during fall 2003 (Table 3-8). The

decrease in tuber production is important because this is how the weed is propagated and

a decrease in tuber production will reduce the tuber number in the seed bank, resulting in

a decreased population the following season.










Table 3-8. Tuber production 8 weeks after planting for all proportions of cowpea: weed.
% Weed Tuber Number Tubers/Plant Dry Weight Per Plant
Fall Spring
g g
0
25 56.0 14.0 1.8 a 6.9 1.1
50 136 17.6 2.5 a 19.8 1.5
75 208 17.4 3.3 a 34.3 1.6
100 283 17.7 15.9 b 41.8 1.8
Significance p < 0.05 NS p < 0.05 p < 0.05 NS
Slope 3.0 0.48
Intercept -17.4 -4.1
R2 0.99 0.97

Relative Yield

Species dry weights are expressed as relative yield to indicate how each species is

performing in mixture relative to performance in monoculture. The relative yield (RY) of

cowpea and yellow nutsedge intersected slightly to the left of the 50:50 proportion,

indicating that cowpea is slightly less competitive (Figure 3-1). Relative yield total

(RYT) was also greater than one, both species contributed more than expected to the total

yield when grown in mixture.

1.50 i


0.30


100:0 75:25 50:50 25:75 0:100
Proportion (Cowpea:Yellow nutsedge)
-U- RYCP A RYNS -* RYT
Figure 3-1. Relative yields of cowpea (RYCP) and yellow nutsedge (RYNS) and relative
yield total (RYT) eight weeks after planting.









Yellow Nutsedge and Sunn Hemp

Where there was significant interaction between proportions and season, data were

sorted by season and the simple effects of change in proportion are presented by season.

For variables where no interaction occurred, the main effects of season are shown in

Table 3-9.

Table 3-9. Mean values of sunn hemp for all variables by experiment fall 2002 and
spring 2003.
Variable Units Fall Spring Significance
Crop height cm 96.4 122 ***
Weed height cm 53.7 50.4 NS
PAR top of canopy tmol m-2s-1 227 708 ***
PAR soil surface % 31.9 28.7 NS
PAR middle of canopy % 68.1 48.6 **
Tuber number 231 268 NS
Tubers per plant 21.7 29.3 *
Tuber dry weight g 17.6 28.8 **
Dry weight tubers per g 1.6 3.0 **
plant
Crop leaf area cm2 6406 9376 *
LAI crop 2.89 4.2 *
Crop leaf area/plant cm2 623 928 **
Weed leaf area/plant cm2 663 554 NS
RY crop 0.63 0.86 *
RY weed 0.68 0.99 *
RYT 1.0 1.5 NS

Plant Heights

Sunn hemp plants were taller in the spring than in fall, however, yellow nutsedge

plants were similar in height both seasons (Table 3-9). Crop heights were not affected

significantly by proportion of yellow nutsedge in the mixture (Table 3-10). Similarly,

weed height was not significantly affected by the proportion of sunn hemp in the mixture.









Table 3-10. Sunn hemp and yellow nutsedge heights taken at 8 weeks after planting.
% Crop Crop Height (cm) % Weed Weed Height (cm)
100 115 0
75 116 25 49.2
50 104 50 53.2
25 101 75 53.1
0 100 52.8
Significance NS Significance NS

PAR

Due to the tall growth habit of sunn hemp, PAR was measured in the middle of the

sunn hemp canopy above the yellow nutsedge, as well as the soil surface. This additional

reading was taken to determine the difference in PAR penetration due to canopy.

Percentage of PAR penetrating the canopy in the fall was about 3 times greater than in

the spring (Table 3-9). There were no significant differences among proportion for the

amount of PAR intercepted in the middle or beneath the canopy (Table3-1 1).

Table 3-11. PAR measurements at soil surface taken and middle of sunn hemp canopy 8
weeks after planting.
% Crop % PAR Middle Canopy % PAR Soil Surface
100 48.8 39.2
75 56.2 33.8
50 65.2 24.0
25 63.2 30.4
0 24.2
Significance NS NS

Leaf Area and LAI

LAI of the crop had a significant linear decrease as proportion of crop in the

mixture decreased (Table 3-12) and there was no interaction between proportion and

season, however the mean LAI of sunn hemp was higher in the spring (Table 3-9). LAI

of yellow nutsedge in response to proportion varied with season (p < 0.05). There was a

significant linear increase as proportion of yellow nutsedge increased in mixture (Table









3-12) for both fall and spring. LAI increased four fold in the fall due to increasing

proportion of nutsedge, only increasing slightly less than 1.5 fold in the spring.

Table 3-12. Leaf area index of sunn hemp and yellow nutsedge.
% Crop LAI Crop % Weed LAI Weed
Fall Spring
100 5.4 0 -
75 4.9 25 1.1 1.7
50 2.6 50 2.8 1.9
25 1.3 75 3.4 2.3
0 100 4.6 2.5
Significance p < 0.05 Significance p < 0.05 p < 0.05
Slope 0.06 Slope 0.04 0.01
Intercept -0.1 Intercept 0.20 1.4
R2 0.92 R2 0.95 0.97

When looking at leaf area on a per plant basis, there was no significant difference

among proportions for either species (Table 3-13).

Table 3-13. Leaf area per plant of sunn hemp and yellow nutsedge.
% Crop Crop % Weed Weed
cm2 cm2
100 744 0
75 919 25 770
50 720 50 652
25 718 75 518
0 100 494
Significance NS Significance NS

Total leaf area of sunn hemp in spring 2003 was 30% greater than fall 2002 (Table

3-9). Leaf area was significantly different due to proportion and decreased linearly as

proportion of crop decreased in mixture (Table 3-14). There was significant interaction

(p < 0.05) between season and proportion for total leaf area of yellow nutsedge; therefore,

effect of proportion was examined by season. The rate of increase was linear in both

seasons as proportion of nutsedge increased for total leaf area of yellow nutsedge (Table

3-14) and the rate of increase in fall was greater then in spring (Table 3-9).









For combined leaf area, the interaction between season and proportion were

significant. In fall 2002, combined leaf area was not significantly different due to

proportion (Table 3-15). However, in spring 2003, combined leaf area was significantly

lower in yellow nutsedge monoculture than all other proportions except when sunn hemp

was present at 25%.

Table 3-14. Total leaf area of sunn hemp, yellow nutsedge.
% Crop Crop % Weed Weed
Fall Spring
cm2 cm2
100 11907 0 -
75 11023 25 2503 3655
50 5762 50 6125 4311
25 2873 75 7405 5019
0 100 10272 5536
Significance p < 0.05 Significance p < 0.05 p < 0.05
Slope 129.5 Slope 98.3 28.9
Intercept -199.6 Intercept 429.7 2743.1
R2 0.91 R2 0.95 0.97

Table 3-15. Combined leaf area sunn hemp and yellow nutsedge.
% Crop Combined Leaf Area
cm2
Fall Spring
100 10450 13364 ab
75 10920 17825 a
50 10539 11421 bc
25 9749 8421 cd
0 10272 5536 d
Significance NS p < 0.05

Tuber Production

The number and dry weight of tubers increased linearly by 58 and 52%,

respectively, when grown in monoculture compared to sunn hemp and nutsedge were

grown in equal proportion (Table 3-16). There was no significant change in the number

or dry weight of tubers produced per plant as proportion increased. This indicates that

the presence of sunn hemp had no effect on yellow nutsedge tuber production.










Table 3-16. Tuber production 8 weeks after planting for all proportions of nutsedge.
% Weed Tuber Number Tubers/Plant Dry Weight Dry Weight/Plant
g
0
25 105 26.2 9.0 2.3
50 218 27.2 19.3 2.4
75 303 25.2 28.0 2.4
100 373 23.3 36.5 2.3
Significance p < 0.05 NS p < 0.05 NS
Slope 3.6 0.36
Intercept 26.8 0.40
R2 0.98 0.99

Relative Yield

The point of intersection for sunn hemp and yellow nutsedge occurred between the

75:25 and 50:50 proportion (Figure 3-2), suggesting that sunn hemp is slightly less

competitive than yellow nutsedge. RYT was greater than one for all proportions

indicating that both species contributed more than expected to the total yield (Figure 3-2).


100:0 75:25 50:50 25:75 0:100
Proportion (Sunn hemp:Yellow nutsedge)
-U- RYSH -A- RYNS -*- RYT
Figure 3-2. Relative yields of Sunn hemp (RYSH) and yellow nutsedge (RYNS) and
relative yield total (RYT) eight weeks after planting.









Velvetbean

There were no interactions between proportion and season for all variables, except

for height of yellow nutsedge. The mean values for both seasons are presented in Table

3-17.

Table 3-17. Mean values of velvetbean for all variables by season fall 2002 and spring
2003.
Variable Fall Spring Significance
Crop height cm 32.8 48.6 ***
PAR top of canopy imol m-2s-1 294 787 ***
PAR soil surface % 9.3 5.9 NS
Tuber number 208 279 *
Tubers per plant 19.8 27.1 *
Tuber dry weight g 15.9 28.7 **
Dry weight tubers per plant g 1.5 2.7 *
Crop leaf area cm2 11772 33499 NS
LAI crop 6.6 15.1 NS
Crop leaf area/plant cm2 1251 3821 NS
Weed leaf area cm2 5420 7600 NS
LAI weed 2.4 3.4 NS
Weed leaf area/plant cm2 503.3 1009 NS
Combined leaf area cm2 13754 3210 NS
RY crop 0.69 0.69 NS
RY weed 0.57 0.72 **
RYT 1.0 1.02 NS

Plant Heights

Velvetbean was taller in spring 2003 than fall 2002 (Table 3-17), however, crop

heights were not significantly different due to proportion of weed in the mixture (Table 3-

18). There was a significant proportion by season interaction (p < 0.05) for yellow

nutsedge height. In the fall, weed height was significantly taller at the 50:50 proportion

than the 25:75 proportion however, was not significantly taller than when grown in

monoculture (Table 3-18). There was a slightly different response in the spring in which

yellow nutsedge was significantly shorter at both the 75:25 and 50:50 proportion than

when grown at the 25% proportion or in monoculture.









Table 3-18. Velvetbean and yellow nutsedge heights taken at 8 weeks after planting.
% Crop Crop % Weed Weed
Fall Spring
cm cm
100 40.4 0 -
75 40.8 25 40.9 a 46.2 a
50 42.2 50 53.9 b 43.9 a
25 39.2 75 47.6 ab 59.0 b
0 100 56.2 b 68.1 b
Significance NS Significance p < 0.05 p < 0.05

PAR

PAR measured above the canopy was much greater in the spring (Table 3-17). The

presence of velvetbean in the mixture significantly reduced the amount of PAR reaching

the soil surface than when yellow nutsedge was grown in monoculture (Table 3-19).

Table 3-19. PAR at soil surface taken at 8 weeks after planting.
% Crop % PAR Soil Surface
100 4.8 a
75 5.5 a
50 7.7 a
25 6.0 a
0 14.1 b
Significance p < 0.05

Leaf Area and LAI

Leaf areas of both velvetbean and yellow nutsedge were greater in spring 2003 than

fall 2002 (Table 3-17). LAI did not change as the proportion of either species increased

in mixture (Table 3-20). Leaf area per plant, total leaf area, and combined leaf area were

also not significant for either species as proportion of the crop in the mixture increased

(Table 3-21 and 3-22).









Table 3-20. Leaf area index per area of box of velvetbean and yellow nutsedge.
% Crop LAI Crop % Weed LAI Weed
100 11.6 0
75 8.6 25 2.33
50 18.4 50 2.0
25 4.8 75 3.0
0 100 4.3
Significance NS Significance NS


I aDle -2 1. Lea


It area per plant ot velvetDean ana yellow nutseage.
% Crop Crop % Weed Weed
cm2 cm2
100 1818 0
75 1525 25 1299
50 4837 50 568
25 1964 75 560
0 100 599
Significance NS Significance NS


Table 3-22. Total leaf area of velvetbean and


yellow nutsedge.


% Crop Crop % Weed Weed % Crop Combined
cm2 cm2 cm2
100 25687 0 100 24766
75 18305 25 5194 75 23499
50 38693 50 4541 50 43233
25 7856 75 6725 25 14581
0 100 9581 0 9581
Significance NS Significance NS Significance NS

Tuber Production

There was a significant linear increase in tuber number and tuber dry weight as the

proportion of yellow nutsedge in the mixture increased (Table 3-23). When species were

grown in equal proportion nutsedge produced 41% fewer tubers than in weed

monoculture. Dry weights increased by 38% when grown in monoculture than in equal

proportion. Tubers produced per plant were not significantly affected by the proportion

of velvetbean in the mixture. Dry weight of tubers did not differ significantly on a per

plant basis due to proportion of nutsedge in the mixture (Table 3-23).










Table 3-23. Tuber production 8 weeks after planting for all proportions of nutsedge.
% Weed Tuber Number Per Plant Dry Weight Per Plant
g
0
25 84.9 21.3 6.4 1.6
50 167 20.9 14.5 1.8
75 315 26.3 30.1 2.5
100 407 25.4 37.9 2.4
Significance p < 0.05 NS p < 0.05 NS
Slope 4.5 0.44
Intercept -35.1 -5.3
R2 0.98 0.97

Relative Yield

The point of intersection is shifted slightly to the right of the 50:50 proportion

(Figure 3-3), indicating velvetbean was slightly more competitive than yellow nutsedge.

RYT was also very close to one at all proportions indicating both species contributed

equally to slightly more than expected to the total yield.


1.25

1.00

0.75

0.50


0.25 -\

0.00 I II
100:0 75:25 50:50 25:75 0:100
Proportion (Velvetbean:yellow nutsedge)
-0- RYVB -A- RYNS -0- RYT

Figure 3-3. Relative yields of velvetbean (RYVB) and yellow nutsedge (RYNS) and
relative yield total (RYT) eight weeks after planting.

Santos et al. (1997) found that tomato was more competitive than yellow nutsedge,

similarly these experiments demonstrated that cowpea and sunn hemp were equally to









less competitive than yellow nutsedge and velvetbean was slightly more competitive.

Experiments performed by Morales-Payan et al. (2003) indicate that aboveground and

belowground interference by yellow nutsedge equally reduce tomato shoot dry weight.

Our experiments suggest that the presence of yellow nutsedge also reduced the biomass

of cover crops with increased proportion of yellow nutsedge in mixture. The number of

nutsedge tubers decreased as the density of cover crop increased in mixture; however, the

number of tubers per plant did not change. Santos et al. (1997) also found that the number

of tubers produced by yellow nutsedge decreased as the number of plants competing in

mixture increased. Morales- Payan et al. (2003) also found that tuber number was

reduced by 20% when tomato is present in the mixture under full competition. Holt and

Orcutt (1991) found that rapid and early emergence of yellow nutsedge allow avoidance

of shading from cotton plants, and so that yellow nutsedge was more competitive than

cotton.

Smooth Amaranth and Cowpea

Cowpea

Replacement series experiments were conducted with the three cover crops and an

annual broadleaf weed species, smooth amaranth, which is also a common weed in

Florida vegetables.

For the majority of smooth amaranth and cowpea variables, no interaction between

proportion and season except for total leaf area, LAI, and height of smooth amaranth

(Table 3-24).









Table 3-24. Mean values of cowpea for all variables by season: spring and summer 2003.


Variable
Crop height
PAR top of canopy
PAR soil surface
Crop leaf area
LAI crop
Crop leaf area/plant
Weed leaf area/plant
Combined leaf area
RY crop
RY weed
RYT


cm
mrol m-2s-1
%
cm2

cm2
cm2
cm2


Spring
46.2
925
19.0
19707
8.9
2150
148.1
16801
0.76
1.03
1.4


Summer
47.3
529
11.9
26362
11.9
2784
164.6
21939
0.80
0.56
1.1


Significance
NS
NS
NS
NS
NS
NS
NS
NS

NS
NS


Plant Heights

Height of cowpea was not affected by the proportion of smooth amaranth in the

mixture (Table 3-25). There was a significant interaction (p < 0.05) between season and

proportion; therefore, effect of proportion on weed height is presented by season. During

the spring, amaranth heights remained unchanged as proportion of cowpea decreased in

mixture (Table 3-25). In summer 2003, smooth amaranth height increased linearly as its

proportion increased in mixture. This could be due to the warmer temperatures and

higher PAR levels in summer, resulting in greater plant growth (Table 3-24).

Table 3-25. Cowpea and smooth amaranth heights taken 8 weeks after planting.
% Crop Crop % Weed Weed
Spring Summer
cm cm
100 48.9 0 -
75 43.9 25 52.6 50.2
50 46.2 50 44.9 51.0
25 47.9 75 45.8 76.7
0 100 41.3 88.6
Significance NS Significance NS p < 0.05
Slope Slope NS 0.56
Intercept Intercept 31.4
R2 R2 0.85









PAR

PAR was not significantly different due to proportion of cowpea in mixture (Table

3-26).

Table 3-26. PAR taken 8 weeks after planting of cowpea and smooth amaranth.
% Crop % PAR Soil Surface
100 12.9
75 13.9
50 8.2
25 26.2
0 16.2
Significance NS

Leaf Area and LAI

LAI of crop responded with a linear increase as proportion of cowpea increased in

mixture (Table 3-27). There was a significant interaction between proportion and season

(p < 0.05) for LAI of smooth amaranth. Although an interaction occurred between

season and proportion, when the means were separated by season there was no significant

difference due to proportion. This is probably due to inconsistent magnitude differences

among the proportions.

Table 3-27. Leaf area index per area of box of cowpea and smooth amaranth.
% Crop LAI Crop % Weed LAI Weed
Spring Summer
100 13.8 0 -
75 11.2 25 0.43 0.59
50 10.7 50 0.61 0.40
25 5.9 75 0.77 0.48
0 100 0.52 0.98
Significance p < 0.05 Significance NS NS
Slope 0.096 Slope
Intercept 4.35 Intercept
R2 0.84 R2









Leaf area per plant of crop did not differ significantly due to proportion (Table 3-

28). Leaf area of smooth amaranth was significantly greater at the 25:75 proportion than

for all other proportions.

Table 3-28. Leaf area per plant of cowpea and smooth amaranth.
% Crop Crop % Weed Weed
cm2 cm2
100 1912 0
75 2072 25 286 a
50 2959 50 140b
25 3254 75 96.9 b
0 100 103 b
Significance NS Significance p < 0.05

Total leaf area of cowpea decreased linearly as its proportion in mixture decreased

(Table 3-29). Due to the interaction between season and proportion, the effect of

proportion on total weed leaf area was assessed by season. Similarly to smooth amaranth

LAI (Table 3-29) there was a significant interaction due to season and proportion,

however, total weed leaf area was significantly different due to proportion when

separated by season (Table 3-29). As the proportion of cowpea decreased in mixture the

combined leaf area declined linearly (Table 3-29).

Table 3-29. Total leaf area and combined leaf area of cowpea and smooth amaranth.
% Crop Crop % Weed Weed % Crop Combined
Spring Summer
cm2 cm2 cm2
100 30590 0 100 30590
75 24860 25 949 1313 75 25845
50 23672 50 1357 879 50 24791
25 13015 75 1711 1060 25 14401
0 100 1161 2181 0 1224
Significance p < 0.05 Significance NS NS Significance p < 0.05
Slope 215.6 Slope 280.7
Intercept 9556.4 Intercept 5334
R2 0.85 ______R2 0.85










Relative Yield

RY of cowpea is represented by a convex curve and the point of intersection

occurred slightly to right of the 50:50 proportion, indicating that cowpea is slightly more

competitive than smooth amaranth (Figure 3-4). RYT was greater than one at all

proportions. Both species contributed more than expected to the total yield.

2.00



1.50 -
T

1.00 T T



0.50 T A T



0.00 L
100:0 75:25 50:50 25:75 0:100
Proportion (Cowpea:smooth amaranth)
-0- RYCP -A- RYSA -*- RYT
Figure 3-4. Relative yields of cowpea (RYCP) and smooth amaranth (RYSA) and relative
yield total (RYT) eight weeks after planting.

Sunn Hemp

There were interactions between proportion and season in the sunn hemp

experiment for the following variables: total crop leaf area, LAI crop, crop height, and

the combined leaf area (Table 3-30).









Table 3-30. Mean values of sunn hemp for all variables by season: spring and summer
2003.
Variable Spring Summer Significance


Weed height
PAR top of canopy
% PAR soil surface
% PAR middle of canopy
Crop leaf area/plant
Weed leaf area
LAI weed
Weed leaf area/plant
RY crop
RY weed
RYT


cm
mrol m-2s-1


cm2
cm2

cm2


51.8
590
31.2
49.9
1067
1568
0.70
203
0.64
0.98
1.3


89.9
341
65.1
54.9
1525
933
0.42
112
0.52
1.1
1.3


Plant Heights

The effect of species proportion in mixture on crop height differed with season (p <

0.05). In spring 2003 there was no significant difference due to proportion when means

were separated by season (Table 3-31). In summer 2003, there was a significant linear

decline in sunn hemp height with increasing proportion of amaranth in mixture. Smooth

amaranth was not significantly different among proportions except when species were

grown in equal proportion, smooth amaranth was significantly taller than when grown in

monoculture.

Table 3-31. Sunn hemp and smooth amaranth heights taken 8 weeks after planting.
% Crop Crop % Weed Weed
Spring Summer
cm cm
100 130 229 0
75 139 212 25 71.1 ab
50 123 176 50 77.3 a
25 124 152 75 70.7 ab
0 100 64.1 b
Significance NS p < 0.05 Significance p < 0.05
Slope 1.1 Slope
Intercept 125.2 Intercept
R2 0.97 R2









PAR

PAR measurements were not significantly different when taken at the middle or

bottom of the canopy (Table 3-32). PAR at the soil surface and middle of the canopy did

not change in response to change of crop: weed proportion in the mixture.

Table 3-32. PAR measurements at soil surface and middle of sunn hemp canopy 8 weeks
after planting.
% Crop %PAR Middle % PAR Soil Surface
100 53.6 61.6
75 43.9 42.9
50 56.4 29.9
25 55.9 38.5
0 67.8
Significance NS NS

Leaf Area and LAI

There was a significant proportion by season interaction (p < 0.05) for LAI of crop.

During both seasons, there is a significant linear decrease in crop LAI as the proportion

of sunn hemp decreased in the mixture (Table 3-33). LAI of smooth amaranth was

similar with all proportions of crop: weed.

Table 3-33. Leaf area index per area of box for sunn hemp and smooth amaranth.
% Crop LAI Crop % Weed LAI Weed
Spring Summer
100 7.2 12.0 0
75 5.8 8.8 25 0.46
50 3.5 4.9 50 0.66
25 2.2 2.6 75 0.64
0 100 0.47
Significance p < 0.05 p < 0.05 Significance NS
Slope 0.06 0.13 Slope
Intercept 0.35 -0.95 Intercept
R2 0.98 0.98 R2

Crop leaf area per plant was unchanged in response to proportion of crop in the

mixture (Table 3-34). Leaf area per plant of smooth amaranth decreased linearly as









proportion of smooth amaranth increased in the mixture, further indicating that smooth

amaranth grows better when in mixture than when in monoculture.

Table 3-34. Leaf area per plant of sunn hemp and smooth amaranth.
% Crop Crop % Weed Weed
cm2 cm2
100 1335 0
75 1347 25 258
50 1168 50 187
25 1334 75 117
0 100 66.9
Significance NS Significance p < 0.05
Slope Slope -2.6
Intercept Intercept 318.1
R2 R2 0.99

There was a significant interaction (p < 0.05) between season and proportion for

total leaf area of sunn hemp. In both spring 2003 and summer 2003, there was a linear

decline as proportion of sunn hemp decreased in mixture (Table 3-35). Total leaf area of

smooth amaranth did not change in response to crop: weed proportion changes. There

was also an interaction between proportion and season (p < 0.05) for combined leaf area

(Table 3-36). During both seasons, combined leaf area decreased linearly with

decreasing proportion of sunn hemp in the mixture.

Table 3-35. Total leaf area of sunn hemp and smooth amaranth.
% Crop Crop % Weed Weed
Spring Summer
cm2 cm2
100 16035 26677 0
75 12804 19514 25 1033
50 7861 10830 50 1496
25 4860 5809 75 1404
0 100 1071
Significance p < 0.05 p < 0.05 Significance NS
Slope 153.8 285.2 Slope
Intercept 772.4 -2114.7 Intercept
R2 0.98 0.98 R2__










Table 3-36. Combined leaf area of sunn hemp and smooth amaranth.
% Crop Combined Leaf Area
Spring Summer
cm2
100 16035 26677
75 14295 20088
50 9550 12132
25 6535 6940
0 1416 726
Significance p < 0.05 p < 0.05
Slope 147.9 260.2
Intercept 2165.7 302.5
R2 0.97 0.99

Relative Yield

Sunn hemp was much less competitive than smooth amaranth (Figure 3-5). The

point of intersection for the RY of sunn hemp and RY of smooth amaranth is located at

the 75:25 indicating sunn hemp must be present at extremely high densities to suppress

smooth amaranth. RYT was also consistently greater than one indicating smooth

amaranth contributed more than expected when in mixture.

2.00






> 1.00







100:0 75:25 50:50 25:75 0:100
Proportion (Sunn hemp:smooth amaranth)
-0- RYSH -A- RYSA -*- RYT
Figure 3-5. Relative yields of sunn hemp (RYSH) and smooth amaranth (RYSA) and
relative yield total (RYT) eight weeks after planting.









Velvetbean

The effect of proportion varied by season for several plant parameters (p < 0.05):

total leaf area of velvetbean, LAI velvetbean, combined leaf area, height of smooth

amaranth, and PAR intercepted below the canopy (Table 3-37).

Table 3-37. Mean values of velvetbean for all variables by season: spring and summer
2003.
Variable Spring Summer Significance
Crop height cm 51.0 61 **
Weed leaf area cm2 1130 732 NS
LAI weed 0.51 0.33 NS
Weed leaf area/plant cm2 145 82.2 NS
RY crop 0.74 0.73 NS
RY weed 1.4 0.8 NS
RYT 1.7 1.3 NS

Plant Heights

Crop heights did not change significantly with increasing proportion of smooth

amaranth (Table 3-38). There was a significant interaction between proportion and

season for height of smooth amaranth. However, when means were separated by season

there was no significant difference due to proportion.

Table 3-38. Velvetbean and smooth amaranth heights taken 8 weeks after planting.
% Crop Crop % Weed Weed
Spring Summer
cm cm
100 54.9 0 -
75 59.1 25 56.3 51.9
50 56.1 50 54.5 38.3
25 53.4 75 51.6 57.8
0 100 36.9 71.2
Significance NS Significance NS NS
Slope Slope

PAR

An interaction occurred between proportion and season for PAR. PAR penetrating

the canopy was significantly lower when velvetbean was present in the mixture at all









proportions than when smooth amaranth was grown in monoculture (Table 3-39). In

summer 2003, there was a significant linear increase of PAR at the soil surface as

proportion of velvetbean decreased in the mixture.

Table 3-39. PAR readings taken at soil surface 8 weeks after planting.
% Crop % PAR Soil Surface
Spring Summer
100 1.3 a 0.9
75 2.7 a 1.2
50 1.4 a 1.6
25 3.9 a 1.7
0 11.9b 2.1
Significance p < 0.05 p < 0.05
Slope -0.01
Intercept 2.1
R2 0.97

Leaf Area and LAI

There was a significant interaction between proportion and season (p < 0.05) for

LAI of velvetbean. In spring 2003, LAI of velvetbean was significantly lower when

grown at 25% of the mixture than all proportions except when grown in equal proportion

to smooth amaranth (Table 3-40). However, there was a linear decline with decreasing

proportion of velvetbean in summer 2003. LAI of smooth amaranth did not change as

proportion of velvetbean changed in the mixture. On a leaf area per plant basis, neither

velvetbean nor smooth amaranth was significant as proportion decreased in mixture for

either season (Table 3-41).

Due to an interaction (p < 0.05) between proportion and season, data were

separated by season for total leaf area of velvetbean. There was a linear decline as the

proportion of velvetbean decreased in mixture for both spring 2003 and summer 2003

(Table 3-42). Smooth amaranth produced a larger leaf area in spring 2003 (Table 3-37).









No significant difference in leaf area occurred due to proportion of smooth amaranth in

mixture (Table 3-42).

Table 3-40. Leaf area index per area of box of velvetbean and smooth amaranth.
% Crop LAI Crop % Weed LAI Weed
Spring Summer
100 15.9 a 34.9 0
75 16.2 a 21.7 25 0.36
50 9.9 ab 14.1 50 0.39
25 7.3 b 7.4 75 0.59
0 100 0.35
Significance p < 0.05 p < 0.05 Significance NS
Slope 0.36 Slope
Intercept -3.0 Intercept
R2 0.95 R2

Table 3-41. Leaf area per plant of velvetbean and smooth amaranth.
% Crop Crop % Weed Weed
cm2 cm2
100 3585 0
75 3499 25 192
50 3323 50 102
25 4069 75 111
0 100 50.9
Significance NS Significance NS

Table 3-42. Total leaf area of velvetbean and smooth amaranth.
% Crop Crop % Weed Weed
Spring Summer
cm22 cm2
100 37138 77593 0
75 35875 48089 25 767
50 21897 31263 50 813
25 16259 16295 75 1329
0 100 814
Significance p < 0.05 p < 0.05 Significance NS
Slope 306.5 802.9 Slope
Intercept 8638.7 -6869.9 Intercept
R2 0.87 0.95 R2__

There was a significant interaction (p < 0.05) between proportion and season for

combined leaf area. In both spring 2003 and summer 2003, combined leaf area decreased


linearly as proportion of velvetbean decreased in mixture (Table 3-43).









Table 3-43. Combined leaf area of sunn hemp and smooth amaranth.
% Crop Combined
Spring Summer
cm2
100 37138 77593
75 36939 48560
50 22890 31896
25 18051 17161
0 669 960
Significance p < 0.05 p < 0.05
Slope 367.3 738.7
Intercept 4772.2 -1698.8
R2 0.89 0.97

Relative Yield

The point of intersection in the spring is shifted to the left of the 50:50 proportion

consistently closer to the 75:25 proportion, indicating that velvetbean is much less

competitive than smooth amaranth (Figure 3-6). RY of velvetbean was only greater than

smooth amaranth at the 75:25 proportion, meaning a large number of velvetbean plants is

needed to suppress a small population of smooth amaranth. RYT was also greater than

one, with both species contributing more than expected in mixture. The same trend

observed with sunn hemp and cowpea was also seen with velvetbean in which smooth

amaranth grows better in mixture than monoculture.










2.50


2.00 -


Z 1.50 -


Z 1.00o


0.50 /


0.00 -
100:0 75:25 50:50 25:75 0:100
Proportion (Velvetbean:smooth amaranth)
-U- RYVB -A- RYSA -*- RYT
Figure 3-6. Relative yields of velvetbean (RYVB) and smooth amaranth (RYSA) and
relative yield total (RYT) eight weeks after planting.

This research indicated that smooth amaranth grew better in mixture than when

grown in monoculture. Similar results were found with this and other Amaranthus spp

(Berry, 2002; Ikeorgu, 1990; Kroh and Stephenson, 1980; Rushing et al., 1985). Results

are also similar to Santos et al., (1998) found that smooth amaranth is a better competitor

than lettuce, however, they also found that lettuce became more competitive with

increased phosphorus fertilizer. Whereas, our results indicated that sunn hemp and

velvetbean were less competitive than smooth amaranth and cowpea only slightly more

competitive. Soybean yield loss increased with increased weed density of palmer

amaranth or redroot pigweed (Bensch et al., 2003).














CHAPTER 4
RESULTS AND DISCUSSION

Additive Experiments

Additive field experiments were conducted to determine the optimal planting

density of three leguminous cover crops for the suppression of smooth amaranth during

the summer fallow between vegetable crops.

Preliminary Experiment

A preliminary field experiment was conducted in Live Oak, FL during the summer

of 2002. Cover crops were planted at fairly high densities ranging from 38-188 plants/m2

for cowpea, 44-220 plants/m2 for sunn hemp and 15-73 plants/m2 for velvetbean. The

population of smooth amaranth was relatively low at a density of five plants/m2. The

results of this study were used to select densities for use in subsequent experiments.

Cowpea

Crop heights, PAR within the canopy and biomass of crop and smooth amaranth

were measured at the end of the ten-week growing season. These variables were

examined individually by crop due to variation in plant population of the cover crop

species.

Cowpea height did not change in response to density (Figure 4-1). PAR was

significantly reduced by all densities of cowpea than weed monoculture (p < 0.05)

(Figure 4-2). Cowpea biomass was the same with all densities (Figure 4-3). Weed

biomass decreased as density of cowpea increased with suppression occurring at the







60


lowest density of 38 plants/m2 with no further change in biomass as cowpea density


increased (Figure 4-3).


100



75



50



25



0



Figure 4-1. Co-


1500


0 25 50 75 100 125
Density (plants/m 2)

vpea heights at 10 weeks after planting (WAP).


150 175 200


0 25 50 75 100 125

Density (plants/m 2)


150 175 200


Figure 4-2. PAR within the cowpea canopy 30.5 cm above the soil surface 10 WAP.


TT



-


T
l T

-I I


1










1000 I
*

T
800 T *
T 1
ST _L T

M 600


*H 400


200



0 25 50 75 100 125 150 175 200
Density (plants/m 2)
cowpea amaranth

Figure 4-3. Biomass of cowpea and smooth amaranth at 10 WAP.

Plant Regrowth

There was regrowth of plants that had not been cut to the ground for both the

cowpea and smooth amaranth (data not shown).

Sunn Hemp

Sunn hemp heights remained the same (216 cm) as densities were increased from

44 to 220 plants per m2 (Figure 4-4). PAR measured at 10 weeks decreased quadratically

as crop density increased, indicating that less light was available for photosynthesis at

higher densities by the smooth amaranth, which was shorter than the sunn hemp (Figure

4-5). Crop dry weights increased linearly as density increased (Figure 4-6); however,

amaranth dry weight declined to 11.4 g, with no further change in amaranth dry weight as

density increased.










300





200





100





n


Figure 4


0 25 50 75 100 125
Density (plants/m 2)
[-4. Sunn hemp heights at 10 WAP.


1000

+

800
y 884 -10.4x + 0.032x2 R2= 0.,


600 -



400 +


150 175 200 225


200 1




0 25 50 75 100 125 150 175 200 225

Density (plants/m 2)
Figure 4-5. PAR within the sunn hemp canopy at 30.5 cm above soil surface 10 WAP.


I I





-i ii ii i i iIi iiiiiiiiIii i iIi










1500
TT
-. 1200 :


900


600 1 y = 2.9x +581 R2= 0.87

300
*


0 25 50 75 100 125 150 175 200 225
Density (plants/m 2)
sunn hemp amaranth
Figure 4-6. Biomass of sunn hemp and smooth amaranth 10 WAP.

Plant Regrowth

Regrowth was minimal for both species and was mainly restricted to plants that had

not been cut well (data not shown).

Velvetbean

Unlike cowpea and sunn hemp, there was a significant linear increase in plant

height as density of velvetbean increased. This trend is could be due to the vining growth

habit with the ability to twine around surrounding plants (Figure 4-7). PAR decreased

quadratically as density of velvetbean increased, with the lowest measurements taken at

58 and 73 plants/m2 (Figure 4-8). The effect of density on dry weight of velvetbean was

not significant (Figure 4-9). Weed biomass with velvetbean was significantly lower than

its biomass in monoculture, consistently less than 50 grams. Weed suppression occurred

at the lowest density of velvetbean (15 plants/m2) with no further change in weed

biomass as density increased. This indicated that 15 plants/m2 was sufficient to suppress

smooth amaranth when it occurred at densities of 5 plants/m2.





























0 15 30 45 60 7f
Density (plants/m 2)
Figure 4-7. Velvetbean heights at 10 WAP.


1200



900


0 15 30 45 60 75
Density (plants/m2)

Figure 4-8. PAR within the velvetbean canopy at 30.5cm above soil surface 10 WAP.


T

TT



y=0.37x + 33.9 R2 0.87










550
500
450
400 T
5 350 T
300 1
I 250 r
200
150 -
100
50

0 15 30 45 60 75
Density (plants/m 2)
velvetbean amaranth

Figure 4-9. Biomass of velvetbean and smooth amaranth 10 WAP.

Plant Regrowth

Regrowth was minimal for velvetbean and smooth amaranth, similar to cowpea and

sunn hemp and was mostly confined to plants that had not been cut well (data not

shown).

Additive Experiments 2003

Based on the results of the preliminary experiment lower cover crop densities were

selected for evaluation in subsequent experiments, and a higher level of weed infestation

(15 plants/m2) was used.

Cowpea

The densities used in the preliminary experiment were very effective at suppressing

the growth of smooth amaranth. The lowest density of 44 plants/m2 was sufficient to

suppress smooth amaranth, therefore, in the subsequent experiments, cover crop densities

were lowered. Cowpea was planted at six densities ranging from 10 to 50 plants/m2.










Plant Heights

Cowpea plant heights increased significantly until 9 WAP and then a significant

decline occurred by 12 WAP (Figure 4-10). This was due to the plants maturing and

beginning to set seed. There was significant interaction between location and week for

smooth amaranth height, therefore, results are presented by location. Smooth amaranth

height at Citra increased as the season progressed up until week six, with no significant

difference between six and 9 WAP and were significantly shorter by week 12 (Figure 4-

10). At Live Oak, smooth amaranth increased up until 9 WAP and declined by 12 WAP.

Shorter heights at week 12 than at week nine may be due to smooth amaranth reaching

maturity and beginning to die back. There were no significant differences in cowpea and

smooth amaranth height found due to the crop density.


80



60 -







20 -
40 A------


20



0 I I I
3 6 9 12
Week
A cowpea Citra amaranth Live Oak amaranth
Figure 4-10. Cowpea height as affected by time and smooth amaranth height as affected
by time and location.

Crop Canopy

Crop canopy was measured at the lowest density of 10 plants/m2 containing only

one row of plants as well as at 30 plants/m2 with three rows within each plot. A










randomly selected plant from the single row or within the middle row of three-row plots

was measured in two directions across the canopy. These two densities were selected to

determine how the crop canopy would be affected by the presence or absence of adjacent

rows. There was a significant interaction among density, week and location (p < 0.05)

for crop canopy. Therefore, data were separated by location and density. Crop canopy at

Citra and Live Oak increased linearly as the season progressed at 30 plants/m2. However,

at 10 plants/m2 canopy increased to its maximum size at week nine at both Citra and Live

Oak.

A location by week interaction also occurred for weed canopy. At Citra, plant

canopy increased peaking at about 8 WAP and declining considerably by 12 WAP

(Figure 4-12). Canopy size at Live Oak increased more slowly in a linear manner as the

weeks progressed. Therefore, although amaranth plants were still growing in Live Oak

12 weeks after transplanting they had begun to die back at Citra.

4000
I


3000


2000 y = 380 -1402 R2= 0.87
2000


1000 :--y 156.8x-179.8 R2= 0.90


0
3 6 9 12
Week
0 Citra 10 Live Oak 10 A Citra 30 0 Live Oak 30
Figure 4-11. Crop canopy of cowpea as affected by location and density at 10 and 30
plants/ m2.










2000
y =-1633 + 832x-52.7x2 R2= 0.99
T
1500


S1000


500 T y =23x+9.9 R2= 0.90
T
ST T .....---------
T -Q----------------------- I
0 --
3 6 9 12
Week
Citra 0 Live Oak
Figure 4-12. Smooth amaranth canopy as affected by location and week.

PAR

At Citra by week three, the PAR penetrating to ground level did not change as

cowpea density increased (Figure 4-13). However, by week six crop canopy had begun

to close at all densities and linear decline in PAR with increasing density occurred so that

at the highest density of 50 plants/m2 PAR was only 15%. By week nine, PAR with

densities > 30 plants/m2 was less than 10lmol m2sI as a result of canopy closure at these

densities. By 12 weeks the canopy had closed even at the lowest density of 10 plants/m2,

so that PAR did not differ significantly due to density of cowpea. PAR penetrating the

canopy in weed monoculture plots also decreased as the season progressed.

At Live Oak, there was a linear decrease in PAR at week three as the density of

cowpea increased (Figure 4-14). When measurements were taken at week six the crop

canopy had begun to close and there was a dramatic linear decrease in PAR penetrating

the canopy as the cowpea density increased. At week nine the lowest PAR levels were

attained at 20 plants/m2 with no further decrease with increased densities indicating that

canopy closure had occurred. The final PAR readings at week 12 were lower then at







69


weeks six and nine for the majority of densities however, there were no significant

differences due to density of cowpea. This increase in PAR can be attributed to weather

problems in the field including a freeze and severe rainfall, which damaged the plants.


0 10 20 30 40 50
Density (plants/m2)
3wk A 6 wk 9 wk D 12 wk

Figure 4-13. PAR penetrating cowpea canopy at Citra as affected by density and time.


0 10 20 30 40 50
Density (plants/m 2)
3 wk A 6 wk 9wk U 12 wk
Figure 4-14. PAR penetrating the cowpea canopy at Live Oak as affected by density and
time.










Plant Biomass

An interaction occurred between density and week for total biomass produced

during the season (p < 0.05). A linear increase in biomass at week six was observed as

density of cowpea increased (Figure 4-15), however, as the plants grew throughout the

season the nature of the response changed. At week 12, dry biomass increased

quadratically with increased density of cowpea. By 6 WAP cowpea biomass at Citra was

about 50% less than at Live Oak (Table 4-1). However, by 12 WAP the more rapid

growth of cowpea at Citra resulted in 50% more biomass at Citra than at Live Oak.

There was no significant effect of density on amaranth biomass (Table 4-2);

however, the main effects of location and week were significant (p < 0.05). Weed

biomass 120.7 g m2 at Citra, which was higher than the 12.9 g m-2 recorded at Live Oak.

At week six, weed biomass was 73.6 g m-2 and decreased to 60.1 g m-2 by week 12.

1000

y= 194.50 + 27.5x 0.3x2 R2= 0.93
800 -


^ 600


S5 400 J_


200 y 2.04x + 11.89 R2 0.93
T T
T ...------------ -----------
.0 --- -.......... ,
T -e--------J------------^--- ---------

10 20 30 40 50
Density (plants/m 2)
A 6wk 12 wk

Figure 4-15. Cowpea biomass response to density and week.









Table 4-1. Crop dry weights separated by location. z
Week Citra Live Oak
Dry Biomass
g
6 46.3 a A 99.9 a B
12 875.6 b A 464.6 b B
z -Data in columns followed by the same lower case letter and in rows followed by the same upper case
letter are not significantly different.

Table 4-2. Smooth amaranth biomass by density.
Density Biomass
g
0 72.4
10 73.6
20 68.0
30 58.3
40 59.6
50 68.9
Significance NS

Plant Regrowth

Cowpea and weed regrowth were observed two weeks after termination of the

cover crops. A biomass sample of the weed population was also taken in a IV m2

randomly selected area of each plot to determine the amount of weeds emerging through

the cover crop mulch. At Citra, there was a quadratic decrease in regrowth as the density

of cowpea increased (Table 4-3). At Live Oak, regrowth was the same with all cowpea

densities. There was no weed regrowth observed 2 weeks after harvest. Weed biomass

from regrowth was not significantly different in response density of cowpea mulch, four

weeks after undercutting.









Table 4-3. Cowpea regrowth 2 and 4 weeks after termination and weed biomass 4 weeks
after termination.
Density Citra Live Oak Weed Biomass
% Crop Regrowth % Crop Regrowth g
0 28.7
10 66.3 3.5 3.5
20 66.9 5.5 5.1
30 65.6 4.3 4.3
40 53.1 8.1 0.6
50 46.9 7.6 5.7
Significance p < 0.05 NS NS
Intercept 63.1 -
X 0.5 -
X2 -0.01
R2 0.89 -

Sunn Hemp

Interactions occurred for all variables between week and location or density and

location. Therefore simple effects were evaluated in these situations.

Plant Heights

Sunn hemp height increased linearly and was accompanied by a linear decrease in

smooth amaranth height as sunn hemp density increased (Figure 4-16) at Citra. At Live

Oak, plant heights significantly decreased to 40 plants/m2 and significantly increased

from 60 plants/m2 (Figure 4-16). Smooth amaranth was significantly shorter when sunn

hemp was present at 100 plants/m2 than at 20 plants/m2 or in monoculture. Sunn hemp

plants grew at a faster rate at Citra than at Live Oak (Figure 4-17). With smooth

amaranth, there was a significant increase at Citra until week nine and a significant

decrease by 12 WAP. At Live Oak, smooth amaranth attained maximum height at 9

WAP and did not change during the remainder of the experiment.







73



150
150 ---------
-T -T .. .- - -

y=0.14x+125.4 R2= 0.86
-L
100 T





50 y -0.089x + 45.75 R2 = 0.95


0 --


0 I I I I I I
0 20 40 60 80 100
Density (plants/m 2)
A Citra SH Live Oak SH 0 Citra SA Live Oak SA

Figure 4-16. Effects of crop density and location on sunn hemp and smooth amaranth
heights.

300


250

2 _y= 25.67x -60 R2 =0.99
200 -


S 150


100 .-
-"" y=16.52x -32.3 R2= 0.99
50 .E E


0
3 6 9 12
Week
A Citra SH O Live Oak SH [ Citra SA Live Oak SA
Figure 4-17. Effect of time and location on sunn hemp and smooth amaranth heights.

Crop Canopy

Plant canopies were larger at Citra than Live Oak, 636 cm2, and 347 cm2


respectively (data not shown), and a larger canopy was produced at the lower density of


20 plants/m2 (557 cm2) than at 60 plants/m2 (425 cm2). Canopy size increased in a linear


manner as the season progressed (Figure 4-18). The effect of time on amaranth canopy







74


size varied by location. The response to canopy at Citra increased to a high of 1467 cm2

6 WAP and then significantly decreased to 918 cm2 by 12 WAP. However, at Live Oak,

weed canopy size increased linearly throughout the season (Figure 4-19).


5
C












CT
Q
Figure 4-18.











=


Effe

1800


1500


1200


900


600


300


0


3 6 9 12
Week
ct of time on sunn hemp canopy size.


Week


Citra 0 Live Oak

Figure 4-19. Smooth amaranth canopy size in response to location and week.


y= 36.03x+221.03 R2= 0.91


T







y ....1..-18.1 R 0. 8
.-a 1 y = 44.9x-18.1 R2 0.85
1 1










PAR

There was a significant interaction (p < 0.05) among location, density and time for

PAR. At Citra, PAR penetrating the canopy at week three decreased linearly as density

increased and was much higher than for all other weeks (Figure 4-20). At week six, there

was also a linear decrease in PAR with increasing sunn hemp density with a lower

percentage of ambient PAR reaching the soil than at week three. There was a quadratic

response for weeks nine and twelve due to greater amount of PAR reaching the soil

surface in the weed monoculture at weeks nine and 12. The percentage of PAR was

lowest between 60 and 100 plants/m2. The growth habit of sunn hemp is more upright

and less spreading than the cowpea and velvetbean canopies. The canopy closure

occurred at higher densities with sunn hemp than with cowpea and velvetbean.


100 II


75
o 5 2









0 20 40 60 80 100
Density (plants/m 2)
S 3wk A 6wk S 9wk 12wk
Figure 4-20. PAR penetrating the sunn hemp canopy at Citra as affected by density and
week.

Regression equations:
1) y =-0.17x+94.38 R2 =0.69
2) y =-0.27x + 33.17 R2= 0.96
3) y= 57.87 -1.30x + 0.008x2 R2= 0.95
4) y = 67.48 -1.26x + 0.007x2 R2= 0.98









At Live Oak, the PAR reaching the soil surface linearly declined as the density

increased up until week nine (Figure 4-21). At week 12, PAR was significantly higher at

40 plants/m2 than all other densities.

100 T
Y-- T y =-0.24x+94.58 R2= 0.97





-o y = -0.37x+72.2 R2= 0.72
I.. T
g 50 ...... -- +. ... 1 T


I _L l --- -
25 y=-0.3+55.04 R2= 0.88 ---.
T T


0 I I I I I
0 20 40 60 80 100
Density (plants/m 2)
0 3wk A 6wk 0 9 wk 0 12 wk

Figure 4-21. PAR penetrating the canopy of sunn hemp at Live oak as affected by
density and week.

Plant Biomass

Sunn hemp dry weight had a significant three way interaction among density, time,

and location. The Citra location at week six had a linear increase in dry biomass as sunn

hemp density increased (Figure 4-22). The response at week twelve was quadratic with

dry biomass peaking between 80 and 100 plants/m2. At Live Oak, the effect of density

on dry biomass was not significant (Figure 4-23).

Smooth amaranth grew better at Citra producing a total weed biomass of 121.5 g m-

2 compared with 22.1 g m-2 at Live Oak. Increasing density of sunn hemp caused a linear

decrease in the biomass of smooth amaranth (Figure 4-24). This suggests that further







77


decline in weed biomass could be achieved with higher densities of sunn hemp than were

used in this study.


3000 [ I


2000





1000


0 20 40 60 80 100
Density (plants/m 2)
H week 6 week 12


Figure 4-22. Effect of crop density on biomass of sunn hemp taken six and 12 weeks
after planting at Citra.


600





400





0 200


Density (plants/m 2)
* week 6 0


week 12


Figure 4-23. Effect of density on sunn hemp six and 12 weeks after planting at Live Oak.










125


T
100 T

"- y = 97.4x 0.52 R2= 0.88
75


50



25


0 I I I I I I
0 20 40 60 80 100
Density (plants/m 2)

Figure 4-24. Effect of density of sunn hemp on biomass of smooth amaranth.

Plant Regrowth

There was a significant interaction between week and location for crop regrowth.

At Citra, regrowth was less than 1% and for both times of evaluation (Table 4-4). The

regrowth of sunn hemp at Live Oak was also less than 1% at two and four weeks after

termination. There was no weed regrowth two weeks after termination of the experiment.

At Citra there was a significant quadratic decrease in biomass as density of cover crop

increased (Table 4-5). This may be due to larger amounts of crop residue at high crop

densities. Weed biomass at Live Oak did not differ significantly due to density of cover

crop.

Table 4-4. Sunn hemp regrowth 4 weeks after termination of experiment. z
Week Citra Live Oak
% Crop Regrowth % Crop Regrowth
2 0.2 a 0.25 a
4 0.85 a 0.15 a
z means in columns followed by the same letters are not significantly different.









Table 4-5. Weed biomass at 2 and 4 weeks after termination of sunn hemp.
Weed Biomass
Density Citra Live Oak
g g
0 69.2 2.4
10 42.6 15.6
20 10.8 0.98
30 2.4 4.1
40 4.3 7.0
50 3.4 6.2
Significance p < 0.05 NS
Intercept 70.10
X -3.6
X2 0.5
R2 0.96 -

Velvetbean

Plant Heights

There were two significant interactions (p < 0.05) for crop height of velvetbean:

week by location and density by week. There was a significant linear increase in crop

height as the season progressed at Citra (Figure 4-25). However, at Live Oak, maximum

velvetbean height occurred nine WAP and decreased by 12 WAP. For the interaction

between density and week, crop heights increased weekly although the effect of density

was not significant 3, 6, and 12 WAP (Figure 4-26). 9 WAP, velvetbean grown at 30

plants/m2 were significantly taller than at all other densities.

There were three interactions for smooth amaranth heights when grown in

velvetbean: week by location, density by location and density by week. There was a

significant difference in smooth amaranth height due to location (Figure 4-27). At Citra

maximum smooth amaranth height occurred at 50 cm between weeks six and nine and

then decreased to 37 cm 12 WAP. At Live Oak, smooth amaranth reached a maximum

height of 35 cm between six and nine weeks and the decreased to 31 cm 12 WAP. For










the density by week interaction, there was significant linear decline in smooth amaranth

height at week 12 as density of velvetbean increased (Figure 4-27). Nine WAP smooth

amaranth height decreased until 40 plants/m2. However, the response was not significant

three or six WAP. Although increased velvetbean density caused a linear decrease in

smooth amaranth height at Citra (Figure 4-28) the response to density at Live Oak was

not significant.


80



60



40



20



0-




Figure 4-25.


3 6 Week 9 12

Citra VB 0 Live Oak VB A Citra SA E Live Oak SA

Velvetbean and smooth amaranth heights as affected by week and location.


y=6.1x-1.53 R2=0.98
































Density (plants/m 2)
3wk 0 6 wk A 9 wk IJ
Figure 4-26. Velvetbean heights in response to week and density.


12 wk


T
A T





S y= -0.36x + 43.62 R2= 0.96 *


20 -

T T T T T
T E T


0 I I I I I

0 10 20 30 40 50
Density (plants/m 2)
S3 wk 6wk A 9wk 12 wk
Figure 4-27. Effect of velvetbean density and time on smooth amaranth heights.


T
: I


T T T T
SLT E o


0 I I
A T



T T T T T

I I I II











60



y =-0.28 + 44 R2= 0.88
40 ~




20




0 II I I I I
0 10 20 30 40 50
Density (plants/m 2)
Citra 0 Live Oak
Figure 4-28. Effect of velvetbean density and location smooth amaranth heights.

Plant Canopy

Velvetbean canopy over time varied by location and by density. Crop canopy

increased linearly at both locations but with a more rapid rate of increase at Citra (Figure

4-29) as well as a linear increase for both measured densities. Canopy size increased

more rapidly at 10 plants/m2 than at 30 plants/m2. This can be attributed to more

available space for the plants to expand within the row as well as intraspecfic competition

at the higher density (Figure 4-30). There was also an interaction for smooth amaranth

canopy between week and location. At Citra, smooth amaranth canopy increased to a

maximum of 1248 cm2 at 9 WAP and then decreased to 829 cm2 by 12 WAP (Figure 4-

31); however, the response at Live Oak was not significant. The main effect of density

was also significant (p < 0.05) with the smallest canopy occurring at 30 plants/m2 with a

canopy of 351 cm2, followed by the monoculture at 549 cm2, and the greatest canopy of

793 cm2 at 10 plants/m2.











6000


5000 -
T
0

4000 --'
S T

^ 3000 y = 436.3x -826 R2= 0.85 "- T

I' T' T
2000

T --'. y = 271.45 396 R2= 0.99
1000 ,-



3 6 9 12
Week
0 Citra Live Oak
Figure 4-29. Velvetbean canopy size in response to location and time.


5000



4000 --


3000



2000



1000


3 6 9

Week
S 10 plants m -2 30 plants m -2

Figure 4-30. Effect of time and density on velvetbean canopy size.


T
0
y=444.3x-854 R2O.91-
^


y= 263.46x-367 R2= 0.96






84


1500

T
T I

1000

*I
0

500 T
IT
!T T

I I I i

3 6 9 12
Week
0 Citra Live Oak
Figure 4-31. Effect of time and location on smooth amaranth canopy size.

PAR

The effect of density on PAR was dependent on time and location. Percentage of

PAR reaching the soil surface decreased dramatically from week three to week six

(Figure 4-32). There was a linear decrease in PAR at week three due to increasing

density of velvetbean. At week six there was a rapid decrease in PAR until 20 plants/ m2

to a level of 20 .imol m-2S-1 with no further decline at higher densities. At week nine

PAR was significantly lower at all densities than weed monoculture with the lowest PAR

occurring at 50 plants/m2. At 12 WAP there was a significant decrease in PAR from 70

mrol m-2S-1 with the weed monoculture to 10 imol m-2S-1 with 10 plants/m2 with no

further decrease in PAR as velvetbean density increased. There was a quadratic decrease

at both locations (Figure 4-33) as density of velvetbean increased. The response in PAR

over time differed by location. At Citra, PAR declined to its lowest level by week 6 with

no further decrease over the next six weeks (Figure 4-34). At Live Oak, PAR declined