Title: Myakka
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00089449/00010
 Material Information
Title: Myakka
Series Title: Myakka
Physical Description: Serial
Creator: Department of Soil and Water Science. Institute of Food and Agricultural Sciences. University of Florida.
Publisher: Department of Soil and Water Science. Institute of Food and Agricultural Sciences. University of Florida.
Publication Date: Fall 2003
 Record Information
Bibliographic ID: UF00089449
Volume ID: VID00010
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.


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A i a W S D Publicaio

. Volume 3 Number 3 Institute of Food and Agricultural Sciences

In this issue:

The Importance of 3
Potassium in Flonda
Citrus Ilutntion

Ilutnent Loads in 3
Surface Runoff from
Cattle Ranches in
South Flonda

Chemical Amendments 3
for Soil Phosphorus

Internal Phosphorus -i
Load in Shallo', Lakes

Isolated Wetlands in -
the Lake Okeechobee

Pictures of Lake Okeechobee-
courtesy of the South Florida
Water Management District

Pam Martin
Darryl Palmer
Dr. Vimala Nair


6 sIn this newsletter
we highlight the
Soil and Water
) Science
(SWSD) research
and outreach
activities in the
Lake Okeechobee
Watershed. Lake
t iOkeechobee is a
shallow lake
-fi, (average depth of
2.7 m) located in
south central
Florida, and covers a surface area of 1730 km2. The
watershed of the Lake includes areas south of
Orlando to areas that border the lake on the south,
east, and west, with an estimated area of 1.6 million
hectares. Lake Okeechobee has been defined by the
United States Environmental Protection Agency as an
impaired waterway and new legislation will require
large reductions in phosphorus loads to meet a new
lower Total Maximum Daily Load (TMDL) to the lake.
A TMDL is a target for the total annual amount of a
given nutrient that can enter a particular water body to
meet established goals for maintaining or improving
water quality. The current TMDL for total phosphorus
additions to Lake Okeechobee has been set at 140
metric tons per year with a long-term goal of achieving
a water column phosphorus concentration of 40 parts
per billion by the year 2015, as specified by the Lake
Okeechobee Protection Act (Chapter 0030, Laws of
Florida), which was passed by the Florida Legislature
to establish a restoration and protection program of
the lake.

Our current research and outreach activities as a part
of IFAS initiative are funded by state agencies
including Florida Department of Environmental
Protection (FLDEP), Florida Department of Agriculture
and Consumer Services(FLDACS), and the South
Florida Water Management District (SFWMD). This
interdisciplinary activity is conducted in collaboration
with several IFAS/UF units including: Agricultural and
Biological Engineering, Environmental Engineering
Sciences, Food Resource and Economics, Gulf Coast
REC, Southwest Florida REC, Everglades REC, and
the Okeechobee County Extension Office.


In addition, some of our projects are also conducted
in collaboration with the Archbold Biological Station,
and the DB Environmental Labs, inc. Our research
in this watershed includes: determining (1) strategies
to immobilize excess soil phosphorus and evaluate
BMPs, (2) nutrient management strategies for
cropping systems in the watershed, (3) the role of
isolated and constructed wetlands in phosphorus
retention, and (4) the internal phosphorus flux from
sediments to the water column in shallow lakes in the
watershed including Lake Okeechobee.

Current research and extension activities are our
continued commitment to address soil and water
quality issues in this watershed. During late 1980's
we conducted two major research projects (funded
by the SFWMD)
address the
issues in the
watershed and
the lake, and
since that time
we have
maintained a
modest presence
in this area.
Results of this early research (summarized as special
issue in Ecological Engineering 1995, volume: 5)
were used by state agencies to formulate regulation
and management strategies. This early work
provided impetus for our current research and
extension activities in the watershed. A few examples
of current projects are presented in this newsletter.

The SWSD had a productive 2003 year. Our
graduate enrollment is improving with 70 students on
campus and 17 students in the distance education
program. We are making concerted effort to improve
our undergraduate program. With the addition of
new courses enrollment in our classes is steadily
increasing. Our grant expenditure by Gainesville
faculty for 2003 exceeded $3 million. Approximately
37% funding is from non-federal, 8% from industry,
12% from special federal grants, and 43% federal
agencies. Our extension programs are making a
significant impact around the state in addressing soil
and water quality issues. In 2004, we plan to stay on
course as we meet new challenges and explore new

Dr. ~ ~ K* Raes Redy Chir Soi an Wae Scec Deatet 10 NeelHlBx101, nvriyo lrdansilFoia

Fall 2003




Daniel Herrera MS ad.i1sor R Mvia,.arapu
Mark Lander MS ,d.j.Ior M Collins
Sue Simon MS Ad.isor J White
Ronald Corstanje PhD Ad.,isor V Redd,
Shinjiro Sato PhD Adi..isor N Comerford

Shannon Curtis MS ad.isor J White
Miguel Mozdzen MS "d isor L Wilson
Attani Mukherjee MS Ad isor V' Hair
Jeanne Ragsdale MS "d,`isor i Li
Caroline Rei. MS Ad.iisor J Sartain
TJ Re. MS "d..isor DE Graetz
Cases Schmidt MS Ad isor M Clark
Jeffrey Smith MS .di.sor M Clark
CDa'.'d Stu.ikey MS "d.i1s.or M Clark

Sampson Agyin-Birikorang PhD Ad.isor
GO Connor
in-iberly Epps. PhD Ad. Isor Nl Comerford
Mmn Lu FPhD Ad...isor J Sartain
Ola. ale Oladell PhC' Ad.isor G 0 Connor
Daniel Perkins PhD Ad.isor J Ja. itz
Thomas. Saunders PhD "d..is.or M Collins

Hydric Soils IVV Hurt This ec'l.:Iu i e [raining program foc:uies. on lhe interrelabons. of h-,drolog.,
and h.,dlri.: 5.011i and ho to disctinguiih h.,dric.: 51i from nonh.,dri.: o.1il T three ses10nsi are
offered Mar.:h ':i-11 200- Ma-, -,-':. 00- and Septeniber 1 --1-'. -00 VVade Hurt
I ade_hiurti''Ifa3c. ufl edui

GIS Applications in Soil and Water Science iS G-run aidi This ec.:lui.i e [raining program
fo':icuses on ho t[ make us.e of readily, a ailable geo-data la.,er. of 5.o0c. geology land ui.e and
topography Jul, 2?-2' :i 200-1 abine Grin aid i SGrun ald@ifas. uifl edu


CLr Pedro San.:hez the '00' World Food Prize laIreate directoror of
Tropi.:al -gri.:ulture and Senior Resear.:h S.:holar at [he Earth In.iitute
of Columibia _Ini ersirt, in ie ork Cit, and a M:Carther Fello dell -
ered E T ork Lec.:lure entitled EndrinL funrL e, in 4-afnca 11 fat need to
done The le.:Lire as. attended b., '00 people in.:luding fa:uilt, and

luring his. i1.it to I.IF Lir San:hez is.ited Ith se eral fai:ult., and st.u-
dents. ariou.s IF units. in.: luiding -gronoimn, -gri.:ultural and Eiologi.:al
Engineering Forestr, and 50o1 and Water Sienc:e LCr San:he; as.
hosted b, -gronom., Clepartment c.:hool of Fores.t Res.ouir.:es. and
Conser action and SVVSC

Please plan to attend the 5th Annual SWSD Research Forum on September 2, 2004
Details 'ill be posted in the next ne'-'slettei and the SWS I ebsite



The following have been recognized for their
accomplishments. Congratulations!

Polston Scholarship -Arne Olsen and Dara Park

Robertson Scholarship Kelly Morgan

F.B. Smith Scholarship Leanna Totten

SWSD Award for Excellence in Graduate Studies -
PhD level Hector Castro and Ron Corstanje

SWSD Award for Excellence in Graduate Studies -
MS level Michael Tischler

SWSD Superior Accomplishment Award Abid Al-

Lena Ma was elected as a Fellow of the Soil Science
Society of America

Mary Collins is selected to be the nominee for the
2004 President of Soil Science Society of America

Nick Comerford is selected as Board Member for S-7
Division (Forest Soils) of the Soil Science Society of

Willie Harris received the 2003 SWSD Teacher/
Advisor of the year award

New Soil and Water Science Faculty Member at
North Florida REC, Quincy, FL
Cheryl L. Mackowiak

Dr Ma;:ko, .ak as. born and raised in the Chicago area
She re;ei.ed her BS 11':I84 i and MS i 11''I0i degrees from
Southern Illinois Lin..ersity-Carbondale in the Plant and Soil
Sciences D epartment Fromi 1985 to 1997'I'I she :onducted
research in bioregeneratie life support systems for a ri]So
contractor at the Kennedy Space Center She as respon-
sible for developing the hOrticultural practices and nutritional
requirements of agronomic crops in hydroponic, systems for
long duration space tra-,el and space habitats Her research
Shifted from horticulture to rhizosphere chemiistr,, as. nutrient
recycling strategies from crop residues and human aste
products ere being developed In 1997::I Dr Macko. iak attended itah State IJni-
,ersity -here she recei-ed her PhD in plant nutrtion and soil fertility in 2001 In
2001 to 2003 she '.as employed by the LISDE Forest Ser ice at the Roc.k Mountain
Research Station Logan Utah as. a postdo:ctoral soil scientist to de..elop strategies
for remediating public lands rangeland and .etlands contaminated by selenium and
other trace elements originating from phosphate mining operations in southeast
Idaho In 2004 Dr Macko. iak accepted a faculty position ,,ith the IJFREC in uiincy
to assume the duties of research and e. tension in nutrient BEMP development for
agricultural lands Contact information lclmakco, iak@'ifas ufl edu



IN FLORIDA CITRUS NUTRITION citrus production are
typically dominated by
quartz sand, with very little
clay and organic matter. These soils are extremely low in natural fertility and water-
holding capacity. Managing water and nutrients efficiently on these soils is a chal-
lenging task for citrus production managers. Typically, the nitrogen (N) fertilizer rate
applied to mature citrus ranges between 150 and 250 Ibs/acre. Potassium (K20) is
usually applied at 1.0 to 1.25 times the N rate. While the inefficiency of N fertilizer is
well known, K is usually thought of as an immobile nutrient in most parts of the
world. However, Florida sands have only a small capacity to hold K against leaching
as evidenced by repeated soil testing. Potassium is important in fruit formation and
enhances size, flavor, and color. A shortage of K can result in lost crop yield and
quality. In 1998, funding from the Florida Citrus Producers Research Advisory
Council and the Foundation for Agronomic Research helped us initiate a K fertilizer
experiment in a young southwest Florida grapefruit grove, to evaluate the effect of K
fertilization on yield and fresh fruit quality, and to develop recommendations that will
produce qualities most desired by fresh fruit consumers. Our data suggest that
maximum tree size and yield will occur when fertilizer is applied yearly at 200 to 250
Ibs K20/acre. Visually, trees that received the 200 Ibs/acre rate had an expanded,
branching canopy compared with a tight, bushy appearance of trees that did not
receive K. Fruit size and peel thickness increased with increasing K fertilizer rate,
but brix was maximized at about 200 to 250 Ibs K20/acre. Growers must consider
all factors and strike a balance between them when deciding on the rate of K fertil-
izer to apply. For additional information, contact Tom Obreza at taob@ifas.ufl.edu.

4-year-old grapefruit tree grown on a 4-year-old grapefruit tree grown on a flat-
flatwoods soil with sufficient N fertilizer woods soil with sufficient N fertilizer and
but no K fertilizer. (Notice tight, compact 200 Ibs K20 per acre per year. (Notice more
tree with no visible fruit) branching, expansive tree canopy with
visible grapefruits)



Addition of chemical amendments is seen as one of the
options to increase phosphorus retention and reduce
edge-of-field losses in the Okeechobee Drainage
Basin. Amendments tested include water treatment
residuals (iron, aluminum, and calcium-based), industrial

Beef :artle
ranhing 1' .
the major land
use in the
north of Lake
,n interdirsci-
plinar, pro-

Agro-e olog Flume in mre e.pernental ilaei Led
Re.,earch iCen-
ter M.AERC p in 1998 to e, aminne the influence of cat-
tie stocking densit.S and pasture i tpe on nutrient loads
in surface runoff Ith the goal of de eloping recom-
mendations for Best Manageiient Practies aBMPs
to irpro.e '..ater qualitF on beef cattle ranches in the
region This project reicei ed imalor support froi state
agencies. SFVVWM FLD.-CS and FLDEPp as.. -ell as
the LISD~ and Florida iattleman s Association Pat-
ri k Bohlen rrchbold Biological Station and courtres,
faculnt'r in SVVS[I Yen Campbell i0g &s Bso Eng U.FI
IFASI John Capece Southern Datastrear i and [Don
Graezt ISVVS IF/lIF SI led the after quality co'1mpo-
nents of this project Repl,: ated e, perimental pas-
tires ..ere stocNked at four anirial densities control
o.. 1 medium, and high I and : battle, -ere rotated sea-
sonall, bet.. een ir proved summer pastures 20 ha
and semri-imr proved ,..inter pastures i32 hal Th e e-
perrinental treatm-ients ere iraintained for 5 years
and '..ere disontinued in fall 2 r003 Results heo '. no
significant effects of cattle stock ing density on an,
nutrient parameter mnea3sured Ho. .e.er C:on: entra-
tions of total phosphorus the irimalor nutrient of con-
cern are nearly 5 times greater and total loads ;
times. greater from imipro*...ed than from semi-inmpro.. ed
pastures The greater loads from r iiproved pastures
are apparently, linked to historical phosphorus fertilizer
application Phosphorus fertilizer as applied regu-
larly to the irnpro ed pastures for at least 15-20 ,,ears
prior to 19W,7 at hi.h time 1s. use .S discontinued
Don Graetz and Patrick Bohlen are continuing to ana-
Ize the data from the pastures to link soil phosphorus
characteristics Ith phosphorus. loads in surface ruin-
off For additional information contact Patrick Boh-
len at pbohlen@3archbold-station org

by-products produced or marketed in Florida, and
agricultural amendments (lime and gypsum). The suite of
experimental approaches included lab equilibrations of soil + amendment suspensions to study P solubility
fI reductions, small column studies to quantify phosphorus leaching, and simulated rainfall studies to measure runoff
Phosphorus. A wide range of amendments and rates were used in the lab study, which led to fewer amendments
and rates for use in the leaching study. The list of materials and rates was further reduced in the runoff studies.
The combined results from all studies identified an Aluminum water treatment residual (AI-WTR) from Manatee
Rainfall Simulator County as the material most appropriate for field testing. Performance of amendments in the field will be monitored
(water quality leaving the fields and pasture grass response) for two years. Soil sampling before and with time after
amendment addition will identify changes in soil-phosphorus solubility and form. This project is funded by FLDEP, FLDACS, and SFWMD. For
additional information, contact George O'Connor at gao@ifas.ufl.edu.




Reducing nutrient inputs from nonpoint and point sources of pollution are essential to restoring lake water quality. However, even after external P
load to lakes have been curtailed, internal phosphorus flux from the sediment to the water column can occur, contributing heavily to the degradation
of water quality in lakes. The idea of internal loading is based on the recycling of nutrients from bottom sediments in lakes to the overlying water
column. After load reduction, the internal load of sediments will determine the trophic status of a lake and the amount of lag
time for recovery. Lakes Tohopekaliga (9,840 ha), Cypress (2,200 ha), Hatchineha (7,160 ha), Kissimmee (17,900 ha) and
Istokpoga (11,200 ha) are shallow, eutrophic lakes located in the Upper Kissimmee River Basin. The surface water pH ranges
from 6-8, and secci depth ranges from 0.6-1.2 m for all lakes. The entire Kissimmee River Basin (KRB) comprises 3,013 square
miles; however, the upper basin covers 1600 square miles (USACE 1996). Phosphorus loads exiting these lakes and entering
downstream Lake Okeechobee have doubled over the past 10 years. Consequently, we are determining the relative
contribution of the sediments in each of these lakes to the overall nutrient export.

The equilibrium phosphorus concentration (EPC) can be used to determine whether the internal load will be a problem during
restoration of a lake after load reduction. The EPC is defined as the phosphorus in solution that is in equilibrium with P in the
solid phase or the point where phosphorus is neither being retained nor released from the sediment to the water column. At
water column phosphorus concentrations above the EPC, phosphorus is retained by the sediments and at concentrations
Chakesha Martin, below, the sediments serve as a phosphorus source. The EPC can be a useful tool for water managers to determine which
graduate student sediments may act as a potential source of phosphorus to the overlying water column of a lake. Water managers may consider
sampling in one of dredging a lake as part of restoration; however, dredging is very cost-intensive; so it is important to look at the EPC of a lake to
the lakes determine if it should be dredged for reduction of the export of nutrients to downstream Lake Okeechobee. For additional
information contact John White atjrwh@ifas.ufl.edu.



Wetlands are a prominent feature in the Lake Okeechobee watershed and account for approximately
18% of the land area or just over 21,000 hectares within the four priority basins Isolated wetlands
account for slightly less than half of the total wetlands covering 8,800 hectares or 7% of the land
area. Many of these isolated wetlands have been ditched
and drained overtime to move water off the landscape and
improve pasture conditions for cattle production. However,
enhanced dewatering of the landscape can mean less time
for biological and chemical assimilation of contaminants,
and the potential that nutrients associated with animal
wastes and fertilizer is released to surface or groundwater
where they can have undesirable consequences. Cattle-
men have been proactive in addressing water quality con-
cerns by adopting a BMP manual for Water Quality and
have been offered a presumption of compliance by imple-
mentation of recommended BMPs. One of these BMPs is
to restore or enhance degraded wetlands on pastureland
through the various easement and cost-share programs available to private landowners. Restoration
and integration of wetlands will reduce the total surface runoff from the watershed and provide a
longer detention time for nutrient assimilation by natural processes.

UF/IFAS Extension recently received an award from the
USDA Cooperative State Research, Education and Exten-
sion Service to develop a program to educate landowners
about the attributes of the different wetland enhancement
or restoration programs. This extension program will edu-
cate landowners about the different wetland enhancement
cost-share programs available and will also conduct train-
ing programs for Technical Service Providers, certified by
USDA-NRCS, to assist landowners with their Conserva-
tion Plans. This project will include the development of
various decision-making tools to support educational ac-
tivities for landowners and technical service providers and
will encourage landowners to participate in educational
activities, additional training and participation in one or more wetland enhancement activities or pro-
grams. This program is expected to begin early in 2004. Mitch Flinchum, Mark Clark, and Pat Hogue
are actively involved in this program. For additional information contact Mark Clark at

Visit our new web site on wetlands extension: http://wetlandextension.ifas.ufl.edul


The SVVSD-IF'S and Teagas. Research
Center Johnsto, *n Castle Co VVWeford
Rep of Ireland are jointly hosting an in-
ternational sym-posiLum on Nutrient Man-
agement in Agricultural Watersheds:
A Wetlands Solution, scheduled for
May 2J-1-i, :. 004 in VWe ford Ireland
The symposium., Il pro ide a forum for
snthesis. and interpretation of current
Status on the role of etlandsi to ilrpro e
after r qual1it3 in agricultural c'athments. It
recognizes the interdisciplinary nature of
the topic the di ersirt of researchers
from scientific and engineering dsci-
plines. need to synthesize res-earch infor-
mation on current understanding of et-
land. need to transfer basic research
information to managers in.ol ed in sol -
ing applied problems and to identify fu-
ture directions for design and manage-
iment of treatment wetlands For addi-
tional information contact Raimesh Reddv
at krri'ufl edu

SWS Alumni-vWe are in the process. of updating contact Inforrmation Pleas3e -is.it our ebilte at http s.oils6 ifas ufl eduldepartrient/aluImni html and
update *,our contact information If oui do not ha e 3a.ces. to a ebsite ,'ou can send u5 the updated information In our future ne '..letter .e ouild
like to include alumni ne ',. So please send us information that 'OLu -Ould like to share ,,ith .our friends and colleagues

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