Long-term change in phosphorus behavior and the degree of P saturation in typical cropland after different fertilization practices

Soils with continuous application of fertilizer phosphorus (P) may present high accumulations P and be at risk loss. In this study, we investigated the effects different fertilization strategies on soil dynamics in three typical cropland soils over broad spatiotemporal scales China. The speciation (characterized both by Hedley fractionation 31P nuclear magnetic resonance (31P NMR)) sorption characteristics were examined under five treatments: unfertilized control (CK); chemical nitrogen (N) potassium (K) (NK); N, K (NPK); NPK plus straw (NPKS); manure (NPKM). We found that an increase 100 kg ha−1 cumulative budget, increases Olsen-P CaCl2-P contents ranged 1.98–7.35 mg kg−1 0.46–1.46 kg−1, respectively, among soils. recovery rates (87–111%) much higher than those NMR spectroscopy (40–91%). More percentage organic was detected 31P-NMR acidic soil, while more neutral alkaline Chemical combined or can decrease bond strength (k) values compared to alone, change trends maximum capacity (Qm) dependent types. Moreover, degree saturation (DPS) significantly correlated budget each site. A point relation between DPS carbon (SOC) found. After point, increased 0.63–1.06% as SOC 0.1 g kg−1. Agricultural measures available could effectively, especially amendment, which should carefully considered reduce loss risk.