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IntroductionUnderstanding the P Chemistry In the Everglades Agricultural Area(EAA) Canals.Jaya Das1, Samira Daroub2, Manohardeep S. Josan2 and Timothy Lang21North Florida Research and Education Center, University of Florida, Quincy, FL2Everglades Research and Education Center, University of Florida, Belle Glade, FL

The Everglades Agricultural Area (EAA) is 280,000 ha of rich organic soils. The EAA lies between lake Okeechobee in the north and the Everglades Protection Area to the south.Once a part of the original Everglades, the EAA was channelized and drained for agricultural, residential and commercial purposes in the early 1900s.The EAA is cropped to sugarcane, vegetables, rice and sod. Flat topography in the EAA necessitates drainage which is accomplished through a network of pumps and farm canals and SFWMD (South Florida Water Management District) main canals.Drainage waters from the EAA contributes phosphorus (P) to the downstream ecosystems including the Water Conservation Areas and Everglades National Park.Three main canals chosen for our study Miami, West Palm Beach (WPB) and Ocean canal. Main canals in EAA originate from the lake and end downstream into the Ocean.Sediments in the canals can act as a source or a sink of P, affecting the P concentration in canal waters.Sediments can be resuspended due to flow or wind effects giving rise to turbidity and/or release of nutrients.Dissolved and Particulate P from all different sources end up in main canals.Understanding the main canals can help improve management practices in Storm Treatment Areas(STAs).To formulate possible management practices for canals.

Dissolved and Particulate P from Lake OkeechobeeAverage P conc. 149 ppbRange: 46-884 ppbTotal P load 478 metric tons (2010).Dissolved and Particulate P from EAA farms.Farm Best Management Practices (BMPs), soil properties important.P load169 metric tonsP concentration127 ppbDissolved and Particulate P from EAA farm canals.BMPs for farm canalspump velocity, canal depth and canal maintenance important factors for P load.The canals were constructed by digging till the bedrock, which consists of carbonate deposits.But the soils are mostly organic Histosols reclaimed from draining Everglades wetlandsSo the question lies what are what are the resulting sediment properties?What is the P content of the canal sediments? Are the total P values low or high that would be a concern?What is the mineralogical composition of the sediments? Are there any stable P containing minerals?How are the different P fractions distributed within the total P?Knowledge of sediment properties can help us compare /contrast canal sediments and understand sediment propertiesCurrent load to Storm Water Treatment areas (STAs) range from 96 -264 ppb.

Figure 3. Lake OkeechobeeFigure 4. EAA farmsFigure 5. EAA farm canalsFigure 6. Storm Water Treatment AreasThe problemUnknowns and Research ObjectivesSediments were analyzed for bulk density, loss on ignition (LOI), Total P and pH. LOI is a rough estimate of organic C content. Materials and MethodsSediments were extracted with: 1.0 M KCl, 0.1 M NaOH, and 0.5 M HCl at 298oK using a 1:100 soil : solution ratio. Residual fractions were determined after 6M HCl digestion.The silt and clay size portions (