In May, 1994, the Governing Board approved a Memorandum of Understanding between the District, Archbold Biological Station, and IFAS to begin a long-term research affiliation with the objective to develop environmentally and economically sustainable cow/calf practices in the Lake Okeechobee watershed. The backbone of this effort is the development of a decision support system useful to beef cattle ranchers, a contract for which was approved by the Governing Board in June (with IFAS). This decision support system is to be developed through modifications to an existing decision support system (LOADSS) to make it applicable to beef cow/calf operations. Concurrent with the decision support system development, and the objective of this contract, is the design and construction of field plots at Buck Island Ranch (part of Archbold Biological Station). These field plots will provide an operational, beef cattle ranch setting to conduct realistic experimentation necessary to calibrate and validate the decision sup
This Statement of Work (SOW) describes the design and construction of the field plots, and the collection of baseline data.
BACKGROUND
Florida is one of the major beef
cattle producing states in the Eastern United States with production
centered around cow-calf production. Cas receipts from the sale of beef
cattle (calves included) in 1990 was $390 million (Fla. Crop and Livestock
Rep. Ser., Livestock Summary, 1990). Over 75% of the nutrients required to
maintain a cow and produce a calf come from forages produced on range (9.4
million acres) and pasture (3.0 million acres). These land resources
include many unique and environmentally sensitive ecosystems, such as
wetlands. Florida has experienced and continues to experience a large (750
people/day) flux of people into the state. The water supply for this
expanding urban population originates in large land areas, much of which
are used for beef cattle production. These factors and concern for
maintaining the integrity of the natural ecosystems has stimulated concern
over the impact of beef cattle production practices on water quality and
the environment.
Surface water in south Florida is regulated by the South Florida Water Management District (SFWMD) under Surface Water Improvement and Management (SWIM) Plans. Under the Lake Okeechobee SWIM plan (SFWMD, 1993) phosphorus in surface water runoff from pasture and range cannot exceed 0.35 and 0.18 milligrams per liter, respectively. Ranchers must adjust their management (grazing, fertilization, etc.) to comply with these regulations. In addition, grazing and roller chopping of wetlands (including maidencane ponds) are being scrutinized by the water management districts (SWFWMD, SFWMD) with respect to water quality issues and habitat destruction.
Nitrates in ground water have long been an environmental concern. The connection between nitrate in drinking water and methemoglobinemia is well established and has motivated drinking water standards on the order of 10 milligrams of nitrogen per liter. Nutrient enrichment (nitrogen, phosphorus) in lakes, freshwater ponds, and aquatic slough communities has allowed pollution tolerant species (cattails) to replace native flora and reduce species diversity. Because native flora often developed in a phosphorus-limited ecosystem, natural habitat destruction may be occurring.
The research proposed in the SOW is in support of the overall management goal to develop environmentally and economically sustainable beef cow/calf practices within the Lake Okeechobee watershed as stated in the Memorandum of Understanding for Agro-ecology Research developed by South Florida Water Management District, Archbold Biological Station, and the University of Florida, Institute of Food and Agricultural Sciences. Specifically, the management objectives to which this research contributes is the determination of relationships between agricultural practices and water quality, quantity, hydroperiod, and economic sustainability.
The objectives of this project are to contribute to the above management objective by providing: 1) an opportunity for replicated, experimental manipulation of specified fertilization and grazing practices in both summer and winter pasture settings; 2) Precise measurement of the effects of alternative pasture treatments on water quality parameters and selected biological variables; 3) extrapolation of experimental results to the scale of the full 10,300-acre working cattle ranch; and, 4) empirical results to be used in modeling the impacts of alternative grazing practices on water quality in the Lake Okeechobee watershed.
SCOPE
The experimental approach for this
project and the concurrent development of a decision support system
(Contract No. C-5298 with IFAS) was developed during a research planning
meeting in late January which was attended by representatives from the
District, IFAS, Archbold Biological Station, U.S. Geological Survey, and
the Florida Cattleman's Association. The approach consists of the
following two efforts:
1. Design and Construction of Experimental Pasture Arrays:
Experimental pasture arrays
will be established in two areas on Buck Island Ranch, corresponding to
the two principal pasturing regimes of a typical central Florida ranch.
One array will be on well-drained and improved pasture with bahia-grass,
which is used for summertime (wet season) grazing of cow-calf pairs. The
other array will be on a wetter pasture containing a mix of native
grasses, along with some bahia grass. The second pasture is used for
winter and spring (dry season) grazing by cows immediately after calving
and during the period of exposure to bulls.
The two arrays will be identical in design and instrumentation. Each array will consist of eight contiguous, 50-acre pastures fenced with five-strand barbed wire. Each pasture will be divided into four units (12.5 acres each); gates will provide the option to separate these smaller units to accommodate experiments using rotational grazing, or to join them as a single 50-acre pasture. An alley for movement of cattle will bisect each array, and additional holding pens will be fenced adjacent to the experimental arrays. Each 50-acre pasture must be engineered to be hydrologically independent. Each pasture will have a single exit point for surface water, where instruments will be installed for measurement of water flow and water sampling.
Each array will be equipped with a local meteorological station. Several groundwater wells will be installed in each array to monitor water table depth and overall groundwater quality for the array. A full-time technical assistant will be devoted to installation, troubleshooting, equipment repair, and data retrieval.
2. Enhancement of GIS Database:
The entire 10,300-acre ranch
will be mapped in detail, with an integrated database stored as ARC/INFO
coverages in the GIS Lab at Archbold Biological Station. The existing GIS
database will be enhanced and used both as a tool for storing a multitude
of land management variables through time, and as an example system for
modeling and projection ranch-scale impacts of grazing treatments on water
quality.
A half-time GIS specialist will be employed to develop the data layers required by the models. The following whole-ranch coverages and data files will be developed within the GIS database:
Single, master coverages:
roads, fence lines, and structures drainage and irrigation system gross vegetation features wetland vegetation pasture composition (forage grasses) soil type topography (USGS quad sheet data) soil chemistry
Multiple coverages and attribute files:
fire histories cattle inventories fertilization treatments herbicide treatments rainfall data water quality data Standardized Performance Analysis (SPA) database
WORK
BREAKDOWN STRUCTURE
Task 1: Project Orientation Meeting
Archbold's Principal Investigator(s) will attend a Project Orientation Meeting at the South Florida Water Management District (District) in WPB, Florida within one month of the contract execution date. At this time, Archbold's Principal Investigator will present an overview of the project objectives, project plans and methods, proposed project schedule, decision points, and deliverables. This presentation will serve as an introduction and outline for discussions with District staff. Discussions will cover these topics as well as the time frame and approach needed to provide interim deliverables and final products. After the meeting, Archbold will submit a letter summarizing the conclusions of the meeting, a list of District and Contractor action items, and a list of data and/or information to be supplied by the District.
Deliverables:
1) Ten hard copies of all presentation materials at the beginning of the Project Orientation Meeting, due within 4 weeks after contract execution.
2) Letter report summarizing
conclusions and action items from the Project Orientation Meeting, due two
weeks after the meeting.
2001
