Front Cover

Title: Nutrient Management Education core group newsletter
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00091329/00003
 Material Information
Title: Nutrient Management Education core group newsletter
Series Title: Nutrient Management Education core group newsletter
Physical Description: Serial
Language: English
Creator: Soil and Water Science Department, College of Agricultural and Life Sciences, University of Florida
Publisher: Soil and Water Science Department, College of Agricultural and Life Sciences, University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2004
 Record Information
Bibliographic ID: UF00091329
Volume ID: VID00003
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.


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Table of Contents
    Front Cover
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
Full Text




Best Management Practices for the
Green Industries Research and
Outreach...page 3

A Second Look at Fertilization
Requirements for Perennial Forage
Hay Systems... page 5

On-Fann Demonstration of Soil
Water Movement in Vegetables
Grown with Plasticulture...page 7

Improving Water and Nutrient
Management Practices for Foliage
Plant Production...page 14

Beneficial Uses of Composts in
Florida Vegetable Crops...page 16

A Multi-Disciplinary Approach to
Water Quality Education in
Florida...page 21


Iidii' Thim l\\ii


Nutrient Management Education Core Group Background

Federal, state and regional agencies are working towards formulating regulations for agricultural
operations to reduce nonpoint nutrient source pollution for water quality protection. Several of
our IFAS faculty are currently involved with these agencies for developing Interim BMPs for
various commodities. In all cases these efforts are interdisciplinary requiring frequent interaction
among the UF/IFAS faculty statewide. Several of us feel the need for a stronger coordination
among IFAS faculty in responding to these needs. The creation and successful functioning of the
proposed Nutrient Management Core Group will enhance the credibility of UF/IFAS faculty and
educational resources and create a nodal point for liaison with all the agencies and public that are
interested in the issue. Several land grant institutions have formed similar core groups or self-
directed teams and have developed educational material. We will interact with these institutions
to benefit from their expertise and experience.

In February of 2001, this group coordinated the FDEP319 Prioritization meeting in Gainesville.
This meeting was attended by state agencies and water management districts, growers, many
commodity organizations and IFAS faculty and administration. All comments from this meeting
were compiled in an electronic newsletter and distributed to all participants throughout the state.

Best Management Practices for the Green Industries Research and Outreach
L.E. Trenholm, Environmental Horticulture

Outreach include copies of the manual, a summary guide,
The Green Industries Best Management Practices and CDs with PowerPoint presentations and
(BMP) manual was developed in 2002. This work other references. Survey and quiz responses to
was developed collaboratively by UF-IFAS, the these sessions include:
Florida Department of Environmental Protection
(DEP), Water Management Districts, and 97% of respondents felt that the program met
representatives from many facets of the lawn care their expectations
and fertilizer industry. The primary goal of the 99% knew more about the topics than they
manual is to provide the commercial lawn and previously did
landscape industry with guidelines to reduce non- 98% felt that the training materials would be
point source pollution. Preservation of both used in training programs
water quality and quantity are the main objectives. Average post-test scores increased 15% over
pre-test scores
The outreach program to teach the industry how
to use the manual is entering into its third year. A number of training sessions are scheduled for
To get the educational message of the manual out 2005 throughout the state. To look at the
to all segments of the industry, the BMP schedule or to register for a session, go to http://
Educational Program was developed. In 2003, turf.ufl.edu. There is a link to the BMP Education
over 1,000 workers were trained in training Program on the home page.
sessions held throughout the state. In 2004, we
have trained just over 1200. Training materials
New Research
At this time, there are no plans to make these
BMPs rule. This may change as a result of
increased municipal ordinances regarding lawn
and landscape use and maintenance. In
anticipation of this, DEP has awarded a 5-year
research grant to verify the BMPs for lawn
grasses. Research will be conducted in Gainesville,
Jay, and Ft. Lauderdale to evaluate nutrient
leaching on various home lawn turfgrass species.
Treatments include nitrogen source, rates,
application timing, and irrigation. Lysimeters are
being installed and sampling will be conducted
throughout the season for nitrates and
phosphates. Future work in this project includes
evaluating specific turfgrass P requirements and
determining phosphate leaching from varying rates
of P, effects of winter fertilization on leaching, and
nitrogen source and timing effects on nutrient
leaching. Drs. Bryan Unruh, John Cisar, Jerry
Sartain, and Laurie Trenholm are collaborating on
this state-wide project.
(Continued on page 4)

BMPs for the Green Industries Research and Outreach (cont.)

(Continued from page 3) Following the second and third treatment
application, there was more nitrate in the 7 Ib N
rate leachate than from the other two N rates at
Previous Research all sampling dates except 4 DAT. There were no
In previous turfgrass leaching research, St. differences in nitrate levels between the I and 4
Augustinegrass received different rates of quick- Ib N rates at any sampling date. Clearly, turf
release nitrogen over the growing season. Rates serves as a protective
of either 1, 4, or 7 Ibs of N per 1,000 ft-2 were filter for nitrates unless
applied in three equal applications throughout the excess nitrogen is
year. Lysimeters were placed to a depth of 18" applied at one time. "Clearly, turf
under the soil line and leachate was collected
serves as a
every 3-5 days following treatment application. e
Leachate was analyzed for nitrate concentration protective filter
from all sampling dates. Data were inconsistent in for nitrates
2002 due to problems with leachate collection. unless excess
nitrogen is
In 2003, the effect of nitrogen rate on leaching applied at one
became apparent following fertilizer applications. time."

N Concentration in Leachate
in 2003 from St. Augustinegrass

z 20 .


4 5 10 16 24

GNV Days After Treatment

A Second Look at Fertilization Requirements for Perennial Forage Hay Systems
C.L. Mackowiak, Soil & Water Science, A.R. Blount, and P. Mislevy, Agronomy

Sthe needed data to help optimize fertilizer
recommendations while minimizing fertilizer losses
to the environment.

S.-. In the spring of 2004, experimental plots (3 x 6 m)
r l i were laid out in established, non-irrigated hay
fields of bahiagrass, bermudagrass and perennial
peanut located at the Range Cattle Research and
Se Education Center (RCREC), Ona (no perennial
Peanutt, the North Florida Research and Education
Center (NFREC), Live Oak and NFREC, Marianna,
'-i.t .t, th to test K fertility practices with and without
supplemental sulfate of potash magnesia. In
contrast, with the University of Florida IFAS forage
recommendations of applying a set amount of
Bahiagrass (Paspalum notatum Flugge), additional N and K following each clipping havingg)
bermudagrass (Cynodon dactylon L.) (Figure I), and these plots received fertilizer based on the
perennial peanut (Arachis glabrata Benth.) are estimated yield from each harvest in an effort to
common forages grown in Florida pastures and hay better tailor fertilizer application to seasonal plant
fields. Potassium deficiency in bermudagrass has demand. For example, in Ona, bermudagrass
been associated with a greater risk of leaf-spot growth does not accelerate appreciably until late
diseases i.e., Helminthosporium spp. which may spring (mid June), and it continues until late
result in yield reductions and stand losses. It is summer (Figure 2).
suspected that dollar spot fungus in bahiagrass and
perhaps even peanut stunt virus in perennial
peanut may be aggravated by low soil Pensacola/Argentine bahiagrass
fertility. Besides effects on plant vigor, the 2.0 (verticalbars=SE)
release of new, higher yielding cultivars of --- Check(nofertilizer)
bahiagrass and bermudagrass are expected 1.5 -0- Low KCI-K
to increase nutrient demand and therefore -g LowKMgS-K
current fertilizer recommendations may -A HighKMgS-K
need to be adjusted. 1.0 -
Low pH and cation exchange capacity
characterize a large portion of Florida soils. 0.5
High annual rainfall adds to the potential
leaching of nutrients, particularly N, K, and
S from the topsoil. Unlike many annual row 0.0
and vegetable crops, the perennial forages May Jun Jul Aug Sep
under study are deeply rooted and can pull Clipping Month
nutrients, such as K, from several feet in the
soil profile, thereby minimizing nutrient
leaching losses. Characterizing and monitoring the
soil fertility with soil depth over time will provide (Continued on page 6)

A Second Look at Fertilization Requirements for Perennial Forage Hay Systems (Cont.)

(Continued from page 5)
There were small yield differences among -.- -
bermudagrass and bahiagrass plots receiving low .- -" '-.
versus high K fertilization and no yield differences '--"-
in perennial peanut plots. However, by -
midsummer, the bermudagrass at Ona was .
moderately chlorotic in plots not receiving the .
sulfate of potash magnesia amendment (Figure 3). ''.. "',.
It is suspected that plants in these plots were S
limited but the plant tissue awaits analysis to
verify the visual assessment. The IFAS
recommendations do not address forage grass N .
Mg or S fertilization requirements but may in the t
future based, in part, on results from this study.
The biggest benefit from K, Mg, or S fertilization
in Florida soils likely will be associated with plant
vigor (resistance to disease and stand
persistence) and improved forage quality. It may
take several years to discern appreciable trends
in stand persistence. Unlike some temperate
forages (i.e., alfalfa), there is not a forage quality
pricing scheme in place for southern forage hay.
While a forage grading system is being developed,
we will gather data that will help the grower
determine if improved fertility returns a premium
forage hay price and thereby respond accordingly
with the appropriate fertility program. applied 550 lb N per acre with half the total
applied in July through August. The IFAS
Although it was not part of this study, N recommendations for the high yield option would
applications greatly increased hay yields (Figure 2) have translated to 560 lb N per acre split equally,
when comparing the check (no fertilizer) with all following each cutting, thereby applying much of
other treatments (N fertilization). Nonirrigated the fertilizer in early spring when growth is
bermudagrass hay yields were over 7 ton per minimal.
acre (12 ton per acre for Ona) in 2004, whereas
bahiagrass and perennial peanut yields reached Additionally, the IFAS N fertilization
over 5 ton per acre, at some locations. recommendations are the same for the higher
Following IFAS recommendations, the Ona yielding bermudagrass and bahiagrass and
bermudagrass plots would have received 560 lb therefore bermudagrass hay production may not
N per acre reach its potential under these
during 2004, whereas our method required the recommendations. We will look more closely at
application of 700 lb N per acre. However, half perennial forage N demand, fertility and N-BMP
of that 880 lbs N was applied in an 8 week period development in future studies.
(July through August) when plant growth was
greatest and the plants likely could utilize the
additional fertilizer. In the case of bahiagrass, we

On-Farm Demonstration of Soil Water Movement in Vegetables
Grown with Plasticulture
Eric Simonne, David Studstill, Bob Hochmuth and Justin Jones, Horticultural Sciences Dept.
Acknowledgment. The authors sincerely thank the
cooperating growers for their time, efforts, and
resources invested in this project. This project was .
supported in part by the Florida Agricultural
Experiment Station and the Southern-SARE on-farm
research program.

Irrigation management is directly linked not only
to yield and economical value of vegetable crops,
but also to the long-term sustainability and
environmental impact of vegetable production. "
Precise knowledge of where irrigation water goes
has direct implications on irrigation management,
fumigant application and fertilizer leaching. The
recommendations of UF/IFAS for irrigation
management for vegetable crops include using a
combination of target irrigation volume, a measure
of soil moisture to adjust this volume based on
crop age and weather conditions, a knowledge of
how much water the root zone can hold, and an
assessment of how rainfall contributes to affects wetted zones. While novel in their
replenishing soil moisture. Improving irrigation approach, these dye tests have used single
management in vegetable crops has been limited irrigation events and were done without an
by the fact that water movement in soil is a actively growing vegetable crop.
process that cannot be easily seen because it
Past educational efforts and fertilization
recommendations have generally attempted to

A direct knowledge of how much water can be reduce environmental impact by reducing fertilizer
stored in the root zone can be gained by application rates. While this approach may be
visualizing water movement in the soil using valid, it is not practical since fertilizer costs only
soluble dye. A blue dye and controlled irrigation represent 10% to 15% of the overall pre-harvest
conditions were used to visualize the wetting production costs. Fertilizer are often applied at
pattern of drip irrigation using different drip tapes rates above the crop nutritional requirement as a
on sandy soils representative of vegetable means to decrease the risk of reduced yields due
producing areas of Florida. As research tools, to shortage of fertilizer, especially close to
these dye tests were used to describe the shape of harvest. We believe that it is possible to follow a
the wetted zone for several water volumes applied different approach for improving fertilizer
by drip irrigation, determine height, width and management. As water is the vehicle for soluble
depth of the wetted zone, and determine if soluble nutrient movement in the soil, it may be possible
fertilizer and the water front represented by the to improve nutrient management by improving
dye move together in the soil. As educational irrigation management. If irrigation water stays in
tools, these dye tests have been used to show the root zone, smaller amount of fertilizer are
growers how deep water moves into several soils likely to be leached. If growers are shown how
and how drip tape flow rate and emitter spacing (Continued on page 8)

On-Farm Demonstration of Soil Water Movement in Vegetables Grown with Plasticulture

(Continued from page 7) Flow rate Emitter
their current irrigation schedules affect water Manufacturer Nominal Relative to Spacing
movement in their fields, they are more likely to (galIlOOft/hr) grower (%) (inch)
understand how water and nutrients are linked. Site I-Cantaloupe
Site I-Cantaloupe
With this integrated approach, sustainability
Roberts 24 100 I2
becomes compatible with economical profitability. Roberts 24 100 12
Aquatraxx 20 83 12
The goals of this project were to demonstrate to Eurodrip 16 67 12
cooperating growers how irrigation and fertilizer
management are linked together and how ite 2-atermelon
management may prevent water movement below Roberts 24 100 12
the root zone. More specifically, the objectives of
this project were to (I) establish a partnership quatraxx 20 83
with three key growers and discuss fertilizer and Eurodrip 16 67 12
irrigation management, (2) determine the position Site 3-Cantaloupe
of the water front throughout the growing season,
(3) diagnose crop nutritional status, and (4) Eurodrip-grower 34 100 12
determine nitrate distribution in the soil profile at
Eurodrip 25 74 12
the end of the growing season. From a producer's
stand point, this information will be used to Aquatraxx 20 59 2
increase sustainability by reducing water used and
environmental impact of vegetable production.
From a regulatory stand point, this information
will contribute to demonstrate the efficacy of The project was conducted in North Florida in
possible nutrient/water Best Management the Spring of 2004 on three commercial vegetable
Practices and set practical management fields (referred to as 'site I-cantaloupe', 'site 2-
expectations. watermelon, and 'site 3-cantaloupe') with three
cooperating growers who had participated in
previous UF/IFAS irrigation management projects
(Simonne et al., 2001). These growers are
"As water is the vehicle for recognized as leaders in water and nutrient
management. The approach was similar at the
solube nutrient movement in three sites. Growers prepared the field with
the soil, it may be possible to raised bed, drip tape and plastic mulch. Sections
of beds were replaced with drip tapes with three
improve nutrient management different flow rates (Table I). Other cultural
by imp g in practices were conducted by the cooperating
grower throughout the growing season (Table 2).
management. If irrigation Soluble blue dye (Terramark SPI High
Concentrate, ProSource One, Memphis, TN) was
water stays in the root zone, injected three times at each site and was traced
smaller amount of fertilizer are through three or four digs (Table 3). Petiole
NO3-N and K concentrations were also
likely to be leached." determined throughout the crop (Table 3) and
compared to published sufficiency ranges
(Maynard et al., 2003). Soil samples were taken in

Cultural practice Site I-Cantaloupe Site 2-Watermelon Site 3-Cantaloupe
Location North Florida North Florida North Florida
Soil type Blanton Fine Sand Plummer Fine Sand
Crop Muskmelon Triploid watermelon Muskmelon
Variety Athena (transplanted) Sugar Heart with 790 pollenizer At (see
Athena (transplanted) Athena (seeded)
(both transplanted)
Crop stage of growth
Planting date March 25 March 23 April I
April 6 (dye injection 1) 2 leaves 6-inch long vines Few plants visible
April 28 (dye injection 2) 2-ft long vines; I-inch fruit 2-ft wide vines; begin bloom 6-inch long vines
May 14 (dye injection 3) Closed rows; 5-inch fruits Closed rows; full-size fruits I -to-2-ft long vines; early bloom
June 2 Harvest Harvest
June 30 Harvest
Irrigation schedule
Early season 1-4 WAT: 50 min/day I-3 WAT: 45 min/day 1-3 WAS 3 x 30 min/day
Mid-season 5-6 WAT: I hr/day 4 WAT: I hr/day as needed
Late season 7 WAT: 1.5 hr/day 5-6 WAT: 2 x I hr/day as needed
8 WAT to harvest: as needed 7 WAT to harvest: 3 xl hr/day as needed
Preplant soil test yes yes yes
Fertilizer schedule Some preplant; weekly injection Some preplant; injection start Some preplant; weekly
throughout the crop after fruit set injections throughout the crop

Site I- Site 2- Site 3-
Cantaloupe Watermelon Cantaloupe
Petiole Sampling and Sap Testing
Petiole I April 28 April 28 April 28 "These growers are recognized

Petiole 2 May 14 May 14 May 14 as leaders in water and nutrient

Petiole 3 June 2 June 2 June 2 management ...Their respective
management ...Their respective
Dye Injection
Dye I April 6 April 6 April 6 fertilizer and irrigation schedules
Dye 2 April 28 April 28 April 28 were considered to be
Dye 3 May 14 May 14 May 14
sophisticated as they took full
Dig I April 28 April 28 April 28 advantage of the flexibility of
Dig 2 May 14 May 14 May 14 drip irrigation to split fertilizer
Dig 3 June 2 June 2 June 2
Dig 4 June 30 June 30 June 30 applications and to change
Soil Sampling irrigation schedules based on
Soil Sample I July I June 30 June 30 plant growth."
plant growth."

On-Farm Demonstration of Soil Water Movement (Cont.)
(Continued from page 8) N,
one-foot increments up to the 6 foot depth at
each location after final harvest. Soil samples '
were dried, sieved to pass a 2-mm screen and i ,
sent to the University if Florida Analytical 0
Research laboratory for N03-N and NH4-N
analysis using methods US EPA 352.3 and 350. I.
Spring 2004 was warm and dry in North Florida; .a.
rainfall marginally contributed to replenishing soil d I 4
moisture and did not interfere with the irrigation Km. f pthsia. 2- Ibamdnnsinne-cntiRin2 o
schedules. Cooperating growers were eager to 70
participate in this project and showed continuous 0"0
interest and support. Their respective fertilizer -Sa
and irrigation schedules were considered to be
sophisticated as they took full advantage of the
flexibility of drip irrigation to split fertilizer
applications and to change irrigation schedules
based on plant growth. Yet, each grower had his 4 0 0' P
own approach to fertilizer management, as the r,,
ratio of preplant:injected and the starting date of ,""""'" I ~,"""---~
injection varied widely. These different
approaches were consistent with current UF/IFAS
fertilizer recommendations. Nitrate-nitrogen and
K concentrations in petioles were all at or above
NON sap testing at the site 1- Cantloupe in Suwannee county. FL in 2004
Sthe sufficiency ranges (Figures. 1, 2, 3).
Drip-tape flow rate had no practical influence on
crop nutritional status. As drip irrigation flow
States ranged from 59% to 100% of all cooperating
growers' rates, this suggests that crop nutritional
__ status could be maintain while reducing fertigation

Soil types were different at the three sites. Soils
0 o TI-e e were sandy at the I -cantaloupe and 2-watermelon
K 1p 6nH. h.t...I- Cnl.t .p. .uin a..nn. ., .p 2004 sites, and was relatively heavier (loamy) at the site
3-cantaloupe. Hence, the positions of the water
S, front as represented by the dye were also
SI- different and are discussed separately (Table 4).
SAt the I-cantaloupe site, the depth of the first dye
Spring ranged between 30 and 38 inches and
averaged 34 inches on April 28. From
transplanting to that date, irrigation applied was
o for transplant establishment and was only 50 min/
S- day (Table 2). Yet, 34 inches is well below the
root zone. On the next dig two weeks later (May
14), the dye injected on April 6 (ISt dye) had
moved only an average of 5 inches deeper. On

SIp,,.* ..,no. Mai y. would be possible to modify the fertilizer
program to include a smaller amount of preplant
nitrogen and increase proportionally that injected
& after plant establishment. While this approach is
I theoretically valid, the feasibility of a 100%
Injected fertilizer program needs to be
Demonstrated first before growers are likely to
adopt it. The second alternative is to change
water distribution in the bed by using two drip
tapes, each with lower nominal flow rates. For
... ... example, if the existing 24 gal/ I 0ft/hr drip tape is
-- replaced by two, 16 gal/1 OOft/hr drip tapes the
same amount of water may be applied by reducing
irrigation time by 25%. Using two drip tapes
-- would reduce by approximately half the vertical
Im movement of water, but would slightly increase
production cost. However, the cost of the
Additional drip tape could be covered through
e .40 e cost-sharing.
-*-AquaaxX2Ogphri C-Euredrip 2upiW gurodrip 3gpUIm S l ag
On June 2, the position of the third dye (injected

Drip tape I Digging date
May 14, the dye injected on April 28 (2nd dye) had Trt. manufacturer April May 14 June 2
No. (Flow rate 28 May 14 June 2
a depth ranging between 16 and 23 inches, with a relative to Dye
19 inches average. The second dye had moved grower's rate) Dye I Dye 2 Dye I Dye 3 2 Dye I
less than the first dye. This is most likely due to Site I Cantaloupe
differences in cantaloupe water use. Small plants Roberts (100) 32 17 35 28 >50 50
(between April 6 and 14) used less water than Aa (%) 38 2 24 >
2 Aquatraxx (83%) 38 23 55 24 >50 >50
larger plants (between April 28 and May 14). This
.. 3 Eurodrip (67%) 33 16 30 14 >50 >50
example confirms the prediction that irrigation 3 Eurodri (67) 33 16 30 14 50 50
water needed early in the season for plant Average 34 19 40 22
establishment may push the water front well Site 2 Watermelon
below the root zone. Changing the existing I Roberts (100%) 24 >45 >45 16 >45 >45
irrigation schedule from I x 50 min/day to 2 x 30 2 Aquatraxx (83%) 21 >45 >45 19 >45 >45
min/day may not be currently practical as it take 3 Eurodrip (67%) 12 >45 >45 II >45 >45
approximately 15 minutes to charge the drip Average 20 >45 >45 15 >45 >45
irrigation system. If this 2 x 30 min/day schedule Site 3 Cantaloupe
were adopted with the current irrigation system,
I Eurodrip-G (100%) -- 22 >40 20 >30 >30
a large (approximately 50%) portion of the
irrigation cycle would be used for system charge, 2 Aquatraxx (74%) 18 30 >40 17 >30 >30
which is likely to decrease uniformity of 3 Eurodrip-UF (59%) -- 38 >40 17 >30 >30
application. A costly possibility to reduce the >
Average 18 30 >40 18 >30 >30
charging time would be to modify the drip Aeage 1 1
irrigation system to keep it continuously
pressurized. If this were not economically
feasible, two alternative practices may be used to
reduce the risk of nutrient leaching. First, it (Continued on page 12)

On-Farm Demonstration of Soil Water Movement (Cont.)
(Continued from page II) At the 3-cantaloupe site, the depth of the first dye
on May 14) ranged between 14 and 28 inches, and ring (injected on April 6, dug on April 28) ranged
averaged 22 inches. Although irrigation was at that between 16 and 18 inches. While roots may be
time several hours daily, large cantaloupe plants found at the 18-inch depth when cantaloupe plants
that were setting fruits used a large amount of are fully grown, this depth was below the root
water. The effect of drip tape flow rate was depth when the plants were at the 6-inch long
detectable only between digs 2 and 3. Reducing vines. On May 14, the dye injected on April 6
drip tape flow rate by 33% (from 24 to 16 could not be found, and the depth of that injected
gal/100ft/hr), reduced the position of the water on April 28 ranged between 22 and 38 inches, and
front on the date of dig 3 by approximately 50% averaged 30 inches. On June 2, the depth of the
(28 vs. 14 inches). Cantaloupe roots were found dye injected on May 14 ranged between 17 and 20
mainly in the plough zone (top 12 inches), but inches, and averaged 18 inches. On June 30, the
several actively growing roots were found in the depth of the dye injected on May 14 was similar to
top 42 inches. These results suggests that that found on June 2: it ranged between 17 and 20
reducing irrigation amount by 25% (by using a drip inches, and averaged 18 inches. Because of the
tape with reduced flow rate) may be instrumental heavier soil texture, water tended to move less at
in keeping the wetted zone within the root zone. this site than at the two other sites. However, it
Therefore, these findings and observations was also observed at this site that the greatest dye
together suggest that it may be possible to keep movement occurred when the plants were small.
the wetted zone within the root zone of Grower's schedules when the plants were fully
cantaloupes on this sandy soils by using two drip grown seemed adequate.
tapes and reducing current grower's schedule by Depth (in) Nitrate (mglkg) Ammonium(mglkg)
25%. Site I Cantaloupe
0-12 0.95 a 5.54 a
12-24 1.07 a 5.17a
At the 2-watermelon site, the depth of the first 24-36 1.04 a 4.24 a
dye ring (injected on April 6 and dug on April 28) 36-48 1.05a 5.20a
ranged between 12 and 24 inches, and averaged 20 48-60 0.74b 5.37a
R2 0.91 0.44
inches. At this site, the depth of the dye ring p-vlue 0.02 0.89
tended to decrease as drip tape flow rate CV() 17 27
decreased. These results suggest that water used Site 2 Watermelon
0-12 1.47 b 5.09 a
for watermelon establishment may be reduced by -12, 2.89 b 2.92 b
approximately 20%. A valve malfunction shortly 24-36 4.78 a 1.91 b
after April 28 resulted in a non-scheduled 6-hour 36-48 2.05 b 1.83 b
48-60 3.25 ab 1.26 b
irrigation event which pushed the water front 2 0.66 0.74
below the 45-inch depth on May 14. The depth of p-value 0.01 0.01
the third dye ring (injected on May 2) and dug on cv(%) 48 51
June 2 ranged between I I and 19 inches, and Site 3 Cantaloupe
0-12 0.90 b 5.3 1 a
averaged 15 inches. These results show that the 12-2 0.72 b 1.30 b
grower's schedule during fruit set and enlargement 24-36 0.97 b 1.32 b
was adequate and did not result in a dye front 36-48 3.27 a 1.37 b
moving deep below the root zone. Lessons from 0.90 0.88
the 2-watermelon site are similar to those from p-value 0.01 0.01
the I-cantaloupe site. In the absence of rain, the CV(% 38 42
risk of the water front moving below the root
zone is greatest during crop establishment and
when plants are small (I to 5 WAT).

Nitrate and ammonium concentrations in the soil of water distribution in the soil profile decreased
significantly varied by depth (Table 5). At the I with depth, as water found paths of preferential
cantaloupe site, all NO3-N concentrations were flow. Hence, leaching may not be uniform in a
below I mg/kg, and were significantly lower at the field even when the uniformity of the drip system
48-60 inch depth. Ammonium concentration was exceeds 90%. Consequently, no consistent
not affected by depth and averaged 5.10 mg/kg practical benefit was found in reducing irrigation
NH4-N between the 0 and 60-inch depth (Fig. 4). rates as an attempt to reduce leaching. However,
At the 2- watermelon site, NO3-N concentration theoretically, reducing irrigation rates should
was significantly greater at the 24-26 inch depth, No3-
while NH4-N concentration was significantly 2o B B 0
greater in the 0-12 inch zone. The hard pan at the .o
3-cantaloupe site limited the depth of soil 1
sampling to 48 inches. Nitrate-nitrogen -
concentration was significantly higher in the 12
inches above the hard pan (36-48 inch depth) than
in the 0-36-inch section, while NH4-N
concentration was higher in the 0-12 inch depth.
These results show that distribution of nitrate and 7
ammonium are different in soils. In a deep sandy NH4-N
soil, N03-N may move vertically rapidly, while it 0 2 B 10
may accumulate above an impermeable layer, and -10
possibly move laterally thereafter. The effect of20 O
drip tape flow rate on the distribution of NO3-N 4
and NH4-N in the soil profile was not significant at 4O &
all three sites.

In conclusion, the irrigation and fertilizer70
schedules used by cooperating growers well I-te -anlom -St 2 -temon iI3 3 Canto
followed UF/IFAS splitting and scheduling
recommendations and well represented proposed
nutrient BMPs. It was not possible to observe the
three dye rings simultaneously at the end of the
experiment, showing that these near-optimal
fertigation schedules did not keep the water front reduce leaching. Another consequence of field
within the root zone for the entire season. At the heterogeneity is that growers tend to irrigate
three sites, greatest water movement was based on the 'dry spots'. This often results in
observed at the beginning of the growing season increasing irrigation on the other parts of the
between I and 5 WAT. This period should be field.
the focus of educational efforts. Cooperating
growers' irrigation schedule were overall This project has demonstrated again the
adequate for the remainder of the season, but importance of soil texture in water movement.
could be reduced by 20%. Using tapes with flow Water moved vertically faster on sandy soils than
rates ranging from 59% to 100% did not practically on the loamy soil. Lateral water movement was
affect crop nutritional status, and water also less on the sandy soil than on the loamy soil.
movement. Cooperating growers' fertigation This project is a good illustration of the fact that
schedule maintain crop nutritional status within the demonstration and implementation of BMPs
the recommended range. are possible when vegetable growers are actively
As observed in previous dye tests, the uniformity involved in it.

Improving Water and Nutrient Management Practices for Foliage Plant Production
Jianjun Chen, Mid-Florida Research and Education Center (MREC), Apopka

Florida leads the nation in foliage plant holistic evaluation of plant species, fertilizer
production. According to the USDA National application rates, container media, and irrigation
Agricultural Statistical Service, the national methods is necessary to learn how to efficiently
wholesale value of foliage plants was $622.7 and effectively use nitrogen and to prevent
million in 2003, of which Florida accounted for leaching/runoff during plant production. In order
$400 million. Florida's dynamic foliage plant to minimize groundwater contamination, we must
industry is characterized by its intensive understand N requirements of and apply N
agriculture as up to 300,000 containerized plants according to each plant's needs, improve media to
may be produced per acre to which 50 to 100 retain water and nutrients, use controlled-release
acre-inches fresh water and 1,000 to 2,000 Ib of fertilizers, and subirrigate and/or recycle irrigation
nitrogen (N) are applied annually. Excessive water.
fertilization and irrigation to container media that
have limited nutrient and water holding capacities Our demonstrations at the MREC and at local
can lead to leaching and/or runoff of up to 50% of nurseries have shown that optimal N rates for
applied fertilizer, primarily N. The combination Anthurium, Dieffenbachia, Epipremnum,
of these factors with Florida's sandy soils and Philodendron, and Spathiphyllum are at least 20%
frequent summer showers could result in N less than traditionally used rates. In addition,
movement into aquifers, causing groundwater amending commercial potting media with selected
contamination. zeolites can reduce nutrient leaching, including N
and phosphorus (P), while the use of controlled-
As a member of the IFAS extension team on release fertilizers significantly reduces N and P
water and nutrient management, we have been
developing best management practices (BMPs) for
foliage plant production. We believe that a "Excessive fertilization

and irrigation to
container media that
have limited nutrient
and water holding
capacities can lead to
leaching andlor runoff
of up to 50% of applied
fertilizer, primarily N."

"We believe that a
holistic evaluation of

plant species, fertilizer
application rates,

container media, and

Ss irrigation methods is
necessary to learn how

to efficiently and
effectively use nitrogen
and to prevent
leaching compared to the use of water-soluble leaching/runoff during
fertilizers. An evaluation of subirrigation
practices, such as ebb-and-flow and flood plant production."
irrigation, showed that quality plants could be
grown with zero runoff of nutrients while using
40% or less water. We also evaluated captured using the pour-through method: if the EC reading
irrigation runoff and rain water for foliage plant is I dS/m, the plant will show nutrient deficiency if
production. Based on the results of 30 foliage no fertilizer is provided; if the EC reading is 2 dS/
and bedding plant species evaluated over a two- m, nutrient levels are adequate; and if the reading
year period, it was concluded that the captured is 3 dS/m or above, the rate or frequency of
water can be used as an alternative irrigation fertilizer application should be reduced. As EC
source for marketable plant production. Each of measurements can be made by growers during
these production options can significantly reduce foliage plant production, the simplified "rules"
nutrient leaching or runoff, and combining the provide growers a convenient way of monitoring
options essentially eliminates nutrient leaching the nutrient status of container media during all
and/or runoff and greatly reduces the amount of production phases.
fresh water used during foliage plant production.
Other nutrient related work has shown that
Additionally, we sampled root-zone solutions silicon application during foliage and orchid
derived from different fertilization practices and production can increase plant resistance to
found that N concentrations in the solutions environmental and cultural stresses. Application
were positively correlated with electrical of a silicon fertilizer in bromeliads and orchid
conductivities (EC). Based on the correlation, we nurseries has significantly reduced Erwinia
have introduced "Chen's 1, 2, 3 Rules" for incidence and saved one nursery more than a
determining the nutrient status of container million dollars by reducing plant losses.
media when root-zone solutions are extracted

Beneficial Uses of Composts in Florida Vegetable Crops
Monica Ozores-Hampton. SWFREC/IFAS, Immokalee

Introduction. Florida is a major vegetable- concentration, C:N ratio, water-holding capacity,
producing state, with 418,000 acres under bulk density, cation exchange capacity, particle
cultivation each year. Sandy soils used to grow size, presence of weed seeds, and odor.
Florida vegetables have low native fertility, so they
require relatively high fertilizer inputs. Minimizing When compost is incorporated into soil,
fertilizer leaching or runoff has become important observed benefits to crop production have been
due to potential negative environmental impacts. attributed to improved soil physical properties
If water and fertilizer conservation could be due to increased organic matter concentration
increased, grower input costs and negative rather than increased nutrient availability.
environmental effects could potentially decrease. Optimum chemical and physical parameters for
composts that might be used in vegetable crop
In recent years, composts produced from a wide production are listed in Table I. Compost is not
range of waste materials have become available in considered fertilizer, however, significant
Florida on a large scale. While environmental quantities of nutrients (particularly N, P, and
regulators are mainly interested in compost trace micronutrients) become bio-available with time as
metal concentrations, growers have different compost decomposes in the soil. Amending soil
interests once compost has passed regulatory with compost provides a slow-release source of
health and safety standards. From a commercial nutrients, whereas mineral fertilizer is usually
vegetable growers point of view, compost quality water-soluble and is immediately available to
is judged based on moisture and nutrient plants. Compost usually contains large quantities
concentration, pH, soluble salts, organic matter of plant-available micronutrients.

-Physical Properties Optimal range Effect

Moisture (%) 35 55 Higher moisture, increased handling and transportation costs

Organic matter (%) 50 or more Higher organic matter lowers application rate

PH 5.0 8.0 In acidic soil, alkaline compost will raise pH

Water holding capacity (WHC) (%) 20 60 Higher WHC leads to lower irrigation frequency

Soluble salts (dSEOm-) less than 6.0 Higher than 6.0 means potential toxicity

Bulk density (lb/cu yd fresh weight) 500 1000 Higher moisture content means a greater bulk density

Particle size Passes I inch screen Increase soil porosity

C:N ratio 15 25:1 Higher C:N ratio causes "N-immobilization"

Maturity (G.I.Y) Over 60 GI lower than 60 indicates phytotoxicity

Compost stability Stable Instability can cause "N-immobilization"

Weed seeds None Uncomposted materials disseminate weeds
SFDACS, 1995.
Y G.I = (% seed germination x root length growth in % of control) /100 (Zucconi et al., 1981 a).

(Continued from page 16)

Crop injury has been linked to use of poor-quality
compost, such as that from early stages of the
composting process. The type and degree of
plant injury is directly related to compost
maturity or stability. Maturity is the degree
to which it is free of phytotoxic substances that
can cause delayed seed germination, or seedling
and plant death; stability is the degree to which
compost consumes N and 02 in significant
quantities to support biological activity, and
generates heat, carbon dioxide (CO2), and water
vapor that can cause plant stunting and yellowing
of leaves. Plant stunting has often been attributed
to high C:N ratio of the organic material before
humification, and plant injury from exposure to
phytotoxic compounds such as volatile fatty acids
and ammonia. Phyototoxin identification in has been reported to increase crop yields of
compost extracts from fresh and 5-month-old bean, blackeyed pea, okra, tomato, squash,
municipal solid waste (MSW) material showed eggplant and bean, watermelon and tomato, corn,
that fresh compost contained acetic, propionic, and bell pepper. In calcareous soil, application
isobutyric, butyric, and isovaleric acids in the rates of biosolids compost as low as 3 to 6 tons/
largest concentrations. Acetic acid at 300 ppm acre resulted in crop yield increases for
concentration inhibited growth of cress seed. tomatoes, squash, and beans. In sandy (Figure 2)
and calcareous soil, MSW compost application
In Florida, soil application of unstable compost rates of 40 tons/acre resulted in crop yield
consistently resulted in "N-immobilization," increases for bean and watermelon.
where available forms of inorganic N were Contradictory crop response results were found
converted to unavailable organic N followed by
growth inhibition of vegetable crops such as
beans, corn, peppers, tomatoes, and squash.
When immature compost is applied and a crop is
planted immediately, growth inhibition and
stunting may be visible for 40 to 60 days
(Figure I). When using compost with C:N ratios
higher than 25 or 30, N fertilizer should be
applied, or planting delayed for 6 to 10 weeks to
allow the compost to stabilize in the soil.
Research on vegetable compost utilization in .
Florida had been established several potential
application: soil amendments, soilborne disease
suppression, biological weed control, alternative
to polyethylene mulch, and as a transplant media.

Compost as a soil amendment.
Amending Florida soil with composted materials
such as biosolids, MSW, and yard trimmings (YT) (Continued on page 18)

Beneficial Uses of Composts in Florida Vegetable Crops (Cont.)
(Continued from page 17) properties such as nutrient concentration or N
mineralization rate, and soil physical and chemical
"If all of Florida's solid waste was properties.
converted to compost, it could Soilborne disease suppression.
The colonization of compost by beneficial
easily be assimilated by the Florida microorganisms during the latter stages of
e n If 20 tonsl composting appears to be responsible for inducing
vegetable industry. If only 20 tons/
disease suppression. Compost does not kill the
acre of compost (fresh weight) pathogens that cause disease as fungicides do.
Instead, compost controls the pathogens by
were applied to each of the keeping the beneficial microorganisms active and

418,000 acres of vegetables growing. Therefore, pathogenic agents will either
not germinate or will remain inactive.
annually grown in Florida, 8.4
In Florida there have been few experiments in
million tons of compost could be vegetable crop production under field conditions
recycled each year." that demonstrate the use of compost in
controlling soilborne pathogens. Municipal solid
waste (MSW) was incorporated into calcareous
when compost was compared to a traditional soil in Dade County at 36 and 72 tons/acre and
fertilizer program. However, combining compost compared to an untreated control. A two-crop
and inorganic fertilizer has generally been more rotation of bush beans and southern peas were
effective in producing a positive plant response
than separate application of either material alone.

One concern of using biosolids or MSW-based
composts is the possible presence of unwanted
elements in the compost and their uptake by
crops. Compost that does not meet EPA 503
standards for metals concentration in biosolids
should not be applied to agricultural land.
Research in Florida on tomatoes and squash
grown on calcareous soil where biosolids, MSW,
and co-composted biosolids-MSW that met the
503 standards were applied showed no trace
metal accumulation in the edible plant parts.

If all of Florida's solid waste was converted to
compost, it could easily be assimilated by the
Florida vegetable industry. If only 20 tons/acre of
compost (fresh weight) were applied to each of
the 418,000 acres of vegetables annually grown in
Florida, 8.4 million tons of compost could be
recycled each year. The actual rate and frequency
of compost use should be determined by compost

seeded. Bean emergence and yield were improved
by 25% in the compost treatment compared to the
untreated control. Ashy stem blight of bean
caused by Macrophomima phasolina was severe in
areas with no compost application, but was almost
completely eliminated where MSW compost had
been applied (Figure 3). MSW compost reduced
the damage by Rhizoctonia root rot in southern
pea considerably compared with the untreated
control. In the areas with no compost application,
severe infections caused plant stunting and
premature death, with significant yield reduction.

Biological weed control.
Weed growth suppression is an important
attribute of surface-applied mulch. An organic
mulch suppresses weeds by its physical presence
as a surface cover, or by the action of phytotoxic
compounds that it contains. Weed seed
germination inhibition by burial under mulch is due soil fumigants. Removal and disposal of
to the lack of growth-promoting factors such as polyethylene mulch has been a major production
light, temperature, or moisture. Chemical effects cost to Florida growers. Therefore, utilization of
of phytotoxic compounds (volatile fatty acids and/ composted waste materials in combination with
or ammonia) in compost can decrease weed seed living mulches in a bell pepper production system
germination. In Florida, a water extract of 3- was investigated. Traditional raised beds were
week-old YT and immature MSW compost covered with polyethylene mulch, MSW (Figure 5),
decreased germination of several perennial and wood chips, or biosolids-YT compost (100 tons/
annual weeds in petri dishes. Under field acre), and bed sides were either planted with a St.
conditions application of immature 4-week-old
MSW compost at 3 inches (45 ton/acre) or
greater thickness completely inhibited weed
germination and growth for 240 days after
treatment (DAT) in vegetable crop row middles
(Figure 4). Inhibition of germination or subsequent
weed growth may be attributed to both the
physical effect of the mulch and the presence of
phytotoxic compounds (fatty acids) in the
immature compost. Similar weed reduction was
obtained with mature MSW compost (100 tons/
acre) in row-middles of bell pepper compared
with an untreated control, but herbicide provided
improved weed control over mature compost.

Alternative to polyethylene mulch.
Polyethylene mulch regulates soil temperature and
moisture, reduces weed seed germination and
leaching of inorganic fertilizer, and is a barrier for (Continued on page 20)

Beneficial Uses of Composts in Florida Vegetable Crops (Cont.)
(Continued from page 19)
Augustine grass living mulch or not planted. Bell
pepper yields were higher on compost mulch plots
than on unmulched plots but lower than on
polyethylene-mulched beds.

Compost as a transplant medium.
The vegetable transplant industry relies on peat
moss as a major ingredient in soilless media. Peat ..
is an expensive, non-renewable resource. In -
Florida, alternative soilless media has been c c C
investigated to grow tomato (Figure 6), 3
watermelon, lettuce, and citrus seedlings. Seed
emergence and seedling growth was similar to
traditional peat:vermiculite media when peat was
partially replaced with compost. Negative growth
effects were reported when the medium was
100% compost, especially when immature,
unstable compost was used.

Checklist for compost utilization on
vegetable crops: 2.Most vegetable crops are sensitive to high
soluble salts, especially when they are direct-
I. Use of immature compost can cause seeded. We recommend measuring the soluble
detrimental effects on plant growth. We salts concentration of a saturation extract. If the
recommend assaying compost for the presence of electrical conductivity (EC) is below 6.0 dS/m, no
phytotoxic compounds using a cress seed salt toxicity should occur. If the EC is above 6.0
germination test. In this test, a compost sample is dS/m, the amended soil should be leached with
saturated with water, and the extract is squeezed water before planting seeds (only a few crops can
from the sample. A portion of the extract is used tolerate this salt level).
to moisten filter paper in a petri dish, on which
cress seeds are placed and allowed to stand for 24 3. High C:N compost can result in N
hours. The germination index (GI) is measured as immobilization. Have the compost analyzed for
GI = [(% cress seed germination x root length in % C:N ratio. If it is above 25:1 to 30:1, some N
of the control)/100]. If GI is less than 60, allow fertilizer applied to the crop may be immobilized
about 90 days between the time of compost due to N immobilization, possibly causing plant N
application and planting of the crop. For example, deficiency.
if cress germination and root length on compost
was 40% and 2 inches, and the control 80% and I 4. Lack of equipment to spread compost in
inch, respectively, therefore we obtained a 50% vegetable fields is a concern. We encourage
cress seed germination and 50 % root length as % compost facilities to play an active role in
of the control. Thus, the GI = 25, indicating developing spreading equipment.
immature compost. An alternative measure is to
continue composting the material to maturity
before it is applied.

A Multi-Disciplinary Approach to Water Quality Education in Florida
Thomas Obreza, Soil & Water Science
Florida's population is 16 million, and 700 new
residents arrive each day. The conversion of rural
to urban land is projected to be 52,000 hectares
per year during the next 20 years. At the same
time, Florida's diverse and competitive agriculture
is expected to remain strong. Florida's sandy
soils, high water tables, nutrient and agrichemical
use, sensitive ecosystems, finite groundwater
aquifers, and limited rainfall storage capacity
present unique challenges to the county agents.
Watershed issues go beyond specialties and
political boundaries. Changes at the urban and
agricultural interface present new challenges to
water resource management and water quality
protection. Each land use has its own Wilson (Environmental Toxicology). This team
characteristic effect on surface and groundwater has conducted annual workshops the last 3 years:
quality. County agents need training in watershed "Managing Water Quality at the Agriculture-Urban
science to better serve clientele. Interface" (2002), "Watershed Management:
Reducing Non-Point Source Pollution" (2003), and
"TMDLs in a Watershed Context" (2004). The
team trained a wide variety of agents (agriculture,
Urban, natural resources, Sea Grant) who were
taught in the classroom, took part in
demonstrations, and went to the field to see
water quality problems and solutions first-hand.

The UF-IFAS interdisciplinary "Watershed
Education Team" was formed by five extension
specialists with expertise in Soil and Water
Science, Agricultural and Biological Engineering,
and Fisheries and Aquatic Sciences to address new
water resource management and water quality
protection challenges presented by urban
development encroachment into agricultural areas. The team evaluated knowledge gain about point
The team includes Tom Obreza (Nutrient and non-point source pollution, Total Maximum
Management), Mark Clark (Wetlands and Aquatic Daily Loads, BMPs, wetland function, and
Systems), Chuck Jacoby (Coastal Ecosystems), estuaries. Pre and post test comparison measured
Sanjay Shukla (Water Resources), and Chris (Continued on page 22)

A Multi-Disciplinary Approach to Water Quality Education (Cont.)

(Continued from page 2 I)
an average knowledge gain of 30%, and The impact of this training will be to:
attendees used their new knowledge to
augment their own educational Increase understanding of water
programs and to aid client decision- quality, runoff effects on surface
making. water quality, non-point source
pollution, and nitrogen and
phosphorus loads
* Explain Best Management Practices,
the value of aquatic plants in
nutrient removal, and pond
S Establish lake management plans
Enhance citizen stewardship
Increase volunteer monitoring at
the county level
SEncourage residents to sample
neighborhood stormwater ponds
Present workshops on water quality
and Total Maximum Daily Loads
Train citizens interested in water
quality protection

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