Intercropping with appropriate nitrogen reduction achieves the trade-off among soil biological health, soil multifunctionality, and crop productivity

Abstract

Context

Intercropping is a typical and sustainable agricultural practice. Specifically, cereal/legume intercropping enhances crop productivity and especially improves nitrogen acquisition and provides the possibility for N (nitrogen) application reduction. However, relatively few studies have explored the influence of intercropping with N application reduction on soil biological health and the corresponding soil function.

Objective

This study aimed to assess the impacts of maize/peanut intercropping on soil biological health and multifunctionality, crop productivity and their relationship, and to further analyze the main factors affecting crop productivity in intercropping systems.

Methods

We investigated the effects of maize/peanut intercropping with three N applications (without N, conventional N application and 20 % conventional N application reduction) within inner rows and in adjacent rows of both crops on soil biological health and multifunctionality as well as crop productivity through a two-year field intercropping experiment. Multiple soil nematode indices were integrated into the soil biological health framework while multiple soil properties pertinent to nutrients were incorporated into soil multifunctionality.

Results

Both intercropping and N application reduction improved soil biological health. Differently, only N application significantly affected soil multifunctionality of maize rows. Intercropping considerably increased maize yields but reduced peanut yields, especially in adjacent rows of both crops, and improved overall land-use efficiency by 3.30 % - 9.33 %. Although conventional N application benefited crop growth and soil multifunctionality rather than biological health, N application reduction still effectively maintained a balance among soil biological health, soil multifunctionality, and crop productivity. Soil biological health and multifunctionality had significant positive effects on maize productivity.

Conclusion

Our findings emphasized that border-row effect improved maize productivity and soil biological health, which all contributed to boosting land-use advantage and crop productivity of intercropping. Intercropping with appropriate nitrogen reduction achieved a trade-off among soil biological health, soil multifunctionality and crop productivity in a short-term experiment, and the long-term effects still need to be further evaluated.

Implications

This study highlights the significant border-row effect not only on crop growth and yield but also on soil biological health. Intercropping with N application reduction strikes an optimal balance between aboveground and belowground ecosystem components.