Phosphorus fertilizer management for high yields in intensive winter wheat-summer maize rotation system: Integrating phosphorus budget and soil available phosphorus.

Overuse of phosphorus (P) fertilizer in crop cultivation accelerates the consistent increase in soil P accumulation and increases the risk of P leaching from the agricultural system. The long-term implications of balanced P management on soil P availability and crop P uptake are still unknown. A three-year field experiment with six different P rates was conducted to determine the effect of a balanced P application strategy on crop yield, P uptake, soil P accumulation, and P transformation in a winter wheat-summer maize rotation system. The results found that the yield and P uptake of summer maize and wheat increased linearly with P fertilization up to 12.5 kg P ha–1, after which they stabilized, and the critical threshold is 50 kg P ha–1 for winter wheat. The soil P budget under agronomic thresholds from 2017 to 2020 was observed as –2.99 to –11.04 kg P ha−1 for maize but 15.1–24.5 kg P ha–1 for wheat. Excessive P fertilization accelerated the downward movement of soil P and stocked it in the deep soil in the form of soil labile P and moderately labile P, increasing the risk of soil P leaching. The annual application of 600 kg ha–1 P fertilizer substantially increased the total P concentration by 30%–99% from deep soil to topsoil compared to the no P treatment, while the 75 kg ha–1 and 150 kg ha–1 P fertilizer treatments did not affect soil P accumulation along the soil profile. Soil Olsen-P concentration to meet crop yield requirements is still far from meeting the critical environmental threshold of 47.6 mg kg–1 and increased slightly by an annual 2.39 mg kg–1 under the balanced P fertilization strategy. An annual negative soil P budget of 3–11 kg ha–1 for summer maize could sustain optimal yields and P use efficiency. Winter wheat cultivation required additional P application to reach the agronomic threshold, set at 15–25 kg ha–1 annually. In conclusion, balanced P fertilization can reduce soil P surplus and subsoil P stock while maintaining crop yields. • The critical P rates for achieving high yields in maize and wheat are 12.5 and 50 kg P ha−1. • The soil Olsen-P level increases by 2.0 mg kg−1 for every 100 kg ha−1 of soil P surplus. • High yields are achieved without a soil P surplus for summer maize but not for winter wheat. • Overuse of P fertilizer leads to the accumulation of labile and moderately P pools in the topsoil and subsoil. • The strategy integrated P budgets and Olsen-P can ensure yields and minimize environmental risks. [ABSTRACT FROM AUTHOR]