Soluble Reactive Phosphorus in Sandy Soils with Commercial Vegetable Production.

Agricultural activities have led to considerable concerns with respect to soil phosphorus for a number of years. Accumulation of phosphorus in soils often happens due to excessive applications of fertilizer and manures. Such accumulation can indirectly cause eutrophication in nearby surface water by runoff with high concentration of phosphorus from the soil during the events of heavy rainfall or improper irrigation. Also, soil phosphorous can be leached into groundwater in well drained sandy soils. This paper presents temporal and spatial distribution of soil soluble reactive phosphorous (SRP) in sandy soils at a commercial vegetable farm with best management practices (BMPs) implemented. The research was conducted in the Suwannee River Basin in northern Florida, USA. Soil SRP was analyzed from the soil samples taken from the grower managed half of a field and the BMP managed half. The results showed that soil SRP was significantly (p < 0.05) higher in the 0 - 0.5 m layer than that in the deeper layers in the soil profile. The yearly average soil SRP from surface to 2 m depth had no significant (p < 0.05) temporal variance at the BMP managed half ranging from 0.99 to 1.99 mg/kg dry soil from 2000 to 2003. At the grower managed half of the field, the yearly average soil SRP in 2003 was significantly (p < 0.05) lower than that in other years with the value of 0.24 mg/kg dry soil. The yearly average soil SRP at the farmer managed half was lower than that at the project managed half in each year from 2000 to 2003.