Effects of Floating Aquatic Vegetation and Environmental Factors on Soluble Reactive Phosphorus in Florida Canals.

Phosphorus has been identified as a contributor to the diminished environmental and water quality of the Everglades National Park.  Water from Lake Okeechobee pass through the Everglades Agricultural Area (EAA) before discharging to the everglades.  Discharges from the EAA have been identified as contributors to the P enrichment of the Everglades. The EAA basin, comprising approximately 250,000 ha of farms is a highly productive agricultural land comprised of near neutral to slightly alkaline organic soils that are used to grow sugarcane, vegetables, sod, and rice.  Management of floating aquatic vegetation (FAV) have been suggested as a potential phosphorus mitigation strategy.  Four pairs of farms (eight total) have been monitored since February 2011 that have involved one of two FAV management strategies: (i) nearly complete control of FAV in main and secondary canals via mechanical removal followed by biweekly spot spraying of recommended herbicides if needed, or (ii) typical control of FAV in main and secondary canals.  Composite and grabs samples for soluble reactive phosphorus were collected bi-weekly or monthly, as well as hourly collection by loggers of supporting data for temperature, pH, oxidation-reduction potential, and specific conductance.  Our results suggest that many factors are contributing to phosphorus retention and release and we hope to move towards better management strategies.