Most agricultural soils in South Florida are very sandy with minimal holding capacities for moisture and nutrients. Repeated application of fertilizers is necessary to sustain high yield of vegetable crops on these soils. However, eutrophication of fresh water systems in this area has been increasingly concerned to the public. Losses of N and P from agricultural fields by means of leaching and surface runoff are suspected as one of the important nonpoint sources. The objectives of this project was to demonstrate the benefits and effectiveness of CaCl₂ application in reducing P losses from vegetable cropping systems while sustaining desired vegetable yield. The results from laboratory incubation and column leaching studies indicate that application of CaCl₂ at 1000-2000 kg/ha can effectively reduce P leaching from sandy soils. The mechanisms of reduced P leaching by CaCl₂ include: 1) conversion of water soluble P into relatively insoluble calcium phosphates; 2) increasing ortho-P adsorption through Ca²⁺ bridging effect; and 3) reduced organic P leaching by enhancing complexing reactions between organic and inorganic colloids at high Ca²⁺ concentrations. The application of CaCl₂ at 1000-2000 kg ha^-1 caused slight decrease in soil pH, but this effect did not persistent because the small amount of acidity replaced by the added Ca was quickly leached out or neutralized. The application of CaCl₂ at 1000-2000 kg ha^-1 did not result in any significant change in soil electrical conductivity (EC) and therefore, any salting effect from the use of CaCl₂ should be negligible. Field trials will be conducted to confirm these findings from the lab and column leaching studies and to further demonstrate the benefits of the CaCl₂ application to vegetable crop production with reduced environmental impacts.