Effects of mineral phosphorus fertilizer reduction and maize straw incorporation on soil phosphorus availability, acid phosphatase activity, and maize grain yield in northeast China

The partial substitution of mineral phosphorus (P) fertilizer by crop straw can mitigate its consumption and losing risk to the environment. However, the changes in soil P availability, acid phosphatase (AcP) activity, and grain yield under mineral P fertilizer reduction and crop straw incorporation remain poorly understood. This study evaluated the effects of a 20% reduction in mineral P fertilizer plus maize straw addition on soil P availability, AcP activity, and maize grain yield, as well as their relationships in a 5-year continually planted maize field in northeast China. Results showed that five years of continuous 20% of mineral P fertilizer reduction and maize straw incorporation significantly increased soil NaHCO3-Po and NaOH I-Pi concentrations, and did not decrease soil labile inorganic P concentration and grain yield compared to the treatment where 100% mineral P fertilizer was applied without straw addition. Additionally, there were significant positive correlations between soil AcP activity, labile inorganic P concentration, and grain yield, indicating AcP might play an important role in maintaining soil P availability and grain yield. Overall, the addition of maize straw can effectively replace 20% of the mineral P fertilizer and could be used as an appropriate fertilization practice in northeast China.