Long-term phosphorus fertilization and soil properties in maize–wheat cropping
摘要
Understanding the long-term effects of phosphorus (P) application on soil physical properties and soil organic carbon (SOC) is essential for sustainable crop productivity. This study investigated the effects of inorganic P fertilizer and its combination with farmyard manure (FYM) on SOC, soil physical properties, and crop yields from an ongoing long-term study on maize–wheat rotation on soils with different Olsen-P status, including seven treatments: P0, P13, P26, P39, P52, P13 + FYM, and P26 + FYM. Results showed that in soils with medium Olsen-P status (MDP, 12.5₋22.5 kg P ha−1), cumulative infiltration (CI) increased with increasing P application rates, with a significant increase of 24.9% observed with 52 kg P ha−1 over no P application. However, no response of CI to P application was observed in high Olsen-P status soils (HDP, > 50 kg P ha−1). The MDP soils in surface soil exhibited a 34.0% increase in water-stable aggregates (WSA) with the application of 39 kg P ha−1 compared to no P application, favouring macro aggregation. The bulk density (BD) increased with P application from 1.50 to 1.65 Mg m−3 in HDP soils, while in MDP soils, it decreased from 1.73 to 1.63 Mg m−3. The highest increase in SOC of 42.5% in HDP and 62.1% in MDP soils was observed with fertilizer P application of 52 kg ha−1 compared to no-P application. The synergy of P and FYM enhanced CI, WSA, and SOC while reducing BD as compared to sole fertilizer P application, regardless of soil P status. P fertilization with 26 kg ha−1 improved soil physical properties in both P-status soils, enhancing P use efficiency and increasing maize and wheat yields. In conclusion, our findings on the long-term impacts of P fertilization across varying P-status soils can be used to develop efficient, sustainable, and environmentally friendly P management strategies that enhance agricultural productivity while conserving soil health.