STUDIES OF PARTICULATE PHOSPHORUS SOURCES AND POTENTIAL MANAGEMENT PRACTICES FOR CONTROL IN THE EVERGLADES AGRICULTURAL AREA

Phosphorus in the drainage waters from the Florida Everglades Agricultural Area (EAA) can have a substantial impact on the receiving waters of the Water Conservation Areas (WCA’s) and the Everglades National Park. Growers in the EAA are required by law to adopt a set of Agricultural Best Management Practices (BMPs) appropriate to their specific operation. The University of Florida Institute of Food and Agricultural Science (IFAS) has been involved in development and implementation of EAA BMPs for over ten years. The original BMP options, adopted in 1995, have resulted in significant reductions of phosphorus export from the EAA. Research subsequent to the issuance of the original set of BMP recommendations has shown that a large fraction of the phosphorus exported from individual farms is in the particulate form, which can account for 40-60% of the total phosphorus load. The physicochemical characteristics of particulate phosphorus (PP) can differ greatly from the soluble inorganic and organic forms of phosphorus, consequently the identification of sources and the elaboration of transport mechanisms is essential for the development of effective control practices. The major sources of PP export have been found to be the biological growth within the farm canal and field ditch systems, rather than soil erosion, so traditional erosion control methods yield minimal benefit. Channel hydraulic conditions can have a major impact on the movement of PP. Growers may readily implement several control options. A number of others are currently under study for the development of economic practices.