Phosphorus loss through surface runoff and leaching in response to the long-term application of different organic amendments on sloping croplands

Abstract

Sustaining crop yield and decreasing the environmental risk of phosphorus (P) loss are key challenges for P fertilization management, which is helpful for achieving the goals for agriculture sustainable development. The effects of the long-term application of different organic amendments on P loss through surface runoff and leaching on sloping croplands have not been studied until now. We simultaneously measured the P loss based on a long-term fertilization experiment using a lysimeter (8 × 4 m2) with four treatments: control (no fertilizer; CK), mineral fertilizer (MF), mineral fertilizer combined with swine manure (MFSM), and mineral fertilizer combined with crop straw (MFCS). Annual P loss loads through surface runoff and leaching in the MF treatment were 90.3 ± 29.4 and 39.2 ± 13.2 mg m−2, respectively. The quantitative relationship between soil P surplus and total P loss load was described by a positive linear function, which suggested that a total P loss of approximately 2.9 kg ha−1 occurred with each 100 kg ha−1 of P surplus. P recovery efficiencies in the MFSM and MFCS treatments increased obviously by 24.0% and 34.5%, whereas soil P surplus decreased by 10.5% and 62.4%, respectively. Overall, the yield-scaled total P losses for the MFSM and MFCS treatments decreased significantly by 71% and 200%, respectively, compared with the MF treatment (0.12 ± 0.04 kg t−1). Long-term organic amendment application, especially for crop straw, effectively decreased P surplus and P loss, thereby increasing P efficiency. We recommend the combined application of mineral fertilizer with crop straw as a sustainable agronomic P management practice to achieve sustainable goals for development of the United Nations and the land degradation neutrality challenge.