Phosphorus availability and environmental risks in potato fields in North Florida

Soil phosphorus (P) availability was compared with Mehlich-1 soil testing and P fractionation at a research farm (RF) and 32 private farms (PFs) in north Florida. The environmental risks caused by P release were evaluated using the P saturation ratio (PSR). Soil Mehlich-1 P at the RF and the PFs was 41.9 +/- 4.1 and 278 +/- 13mg/kg, respectively. The dominant inorganic P fraction for all farms was NaOH-Pi (Al/Fe-bound P) followed by HCl-Pi (Ca/Mg-bound P) at most of the PFs but by NaOH-Po for the RF. Furthermore, the high PSR at the PFs indicated high risks of P loss from soil. To improve P use efficiency and enhance ecological sustainability, better P nutrient management should be implemented for Florida crop production.