The effect of intercropping on phosphorus availability in plant–soil systems: a meta-analysis

Intercropping is an effective practice for increasing crop diversity and achieving sustainable agricultural development, especially in areas with limited agricultural land. Although the nitrogen turnover and trade-off responses of plant–soil systems to intercropping have been extensively studied, quantitative information on the association between P and crop productivity is lacking. Therefore, in this study, we aimed to elucidate the effects of intercropping on plant P concentration, uptake, and use efficiency and soil P availability.

We conducted a quantitative meta-analysis using a database containing 453 comparisons from 56 peer-reviewed studies.

Intercropping significantly increased the soil available P concentration and phosphatase activity by 14.68% and 11.74%, respectively, compared with monocropping. However, the effects of intercropping on other P characteristics and grain yield were not significant. Among the evaluated influencing factors, crop type (cereal or legume) had the greatest effect on soil P availability, followed by soil pH and P fertilizer input. Regression analysis revealed that plant P concentration and uptake were significantly and linearly correlated with soil available P concentration and phosphatase activity. Notably, in maize–legume intercropping systems, maize exhibited increased P concentration and uptake and increased grain yield, whereas legumes exhibited constrained growth.

Overall, we determined that intercropping improves soil P availability, depending on the ecological environment, nutrient management, and intercropping system. This study serves as a valuable reference for effective P fertilizer input in cereal–legume intercropping systems under different management practices.