Phosphorus Accumulation and Sorption in Calcareous Soil under Long-Term Fertilization.

PloS one

PubMedID: 26288011

Wang R, Guo S, Li N, Li R, Zhang Y, Jiang J, Wang Z, Liu Q, Wu D, Sun Q, Du L, Zhao M. Phosphorus Accumulation and Sorption in Calcareous Soil under Long-Term Fertilization. PLoS ONE. 2015;10(8):e0135160.
Application of phosphorus (P) fertilizers to P-deficient soils can also result in P accumulation. In this study, soil P status and P uptake by apple trees were investigated in 5-, 10-, and 15-year-old orchards in the semi-arid Loess Plateau, China, and subset soils with different soil P statuses (14-90 Olsen-P mg kg-1) were selected to evaluate the characteristic P adsorption. Due to the low P-use efficiency (4-6%), total soil P increased from 540 mg kg-1 to 904 mg kg-1, Olsen-P ranged from 3. 4 mg kg-1 to 30. 7 mg kg-1, and CaCl2-P increased from less than 0. 1 mg kg-1 to 0. 66 mg kg-1 under continuous P fertilization. The P sorption isotherms for each apple orchard were found to fit the Langmuir isotherm model (R2 = 0. 91-0. 98). K (binding energy) and Qm (P sorption maximum) decreased, whereas DPS (degree of phosphorus sorption) increased with increasing P concentration. CaCl2-P increased significantly with the increase of Olsen-P, especially above the change point of 46. 1 mg kg-1. Application of surplus P could result in P enrichment in P-deficient soil which has high P fixation capacity, thus posing a significant environmental risk.