Fractionation of Phosphorus Accumulated in Plastic Film House Soils.

Intensive manure application increased gradually the phosphorus (P) content in plastic film house soil in South Korea. To develop effective remediation strategies to minimize phosphorus accumulation in agricultural lands and environmental pollution, it is necessary to characterize the complex forms of phosphorus accumulated in plastic film house soils. Three types of soils were collected from the surface soils (0~15 cm) at on-farm fields applied successively with diary, pig and poultry manure for 3~10 years. We used a sequential fractionation procedure (Modified Chang and Jackson method) for inorganic P, NaHCO₃ method for total P (T-P) and X-ray powder diffraction (XRD) for P precipitates. Average T-P contents in three types of soils ranged from 1,774 ~ 2,424 mg kg^-1. Inorganic P were dominant as 83~88% of T-P. Fe bound P, Al bound P, and Ca bound P were the highest in soils applied pig manure, diary manure, and poultry manure, respectively. β–TCP [(β-Ca₃(PO₄)₂] was identified in soils with diary and poultry manure  using XRD but other P precipitates were not found.