Intercropping of non-leguminous crops improves soil biochemistry and crop productivity: a meta-analysis.

Plant species-rich systems tend to be more productive than depauperate ones. In agroecosystems, increasing crop plant diversity by including legumes often increases soil nitrogen (N) and improves soil fertility; however, such generality in outcomes of non-leguminous crop mixture is unknown. Here, through a meta-analysis of 174 individual cases, we explored the current global research trend of intercropping of exclusively non-leguminous crops (IC) and quantified its effect on agroecosystem productivity key metrics, for example crop plant health, soil chemistry, and microbial community under diverse experimental conditions. IC increased plant biomass and disease suppression and provided a notable yield advantage over monocultures. In addition to phosphorus and potassium, IC also increased plant-available soil N, which, along with increased soil microbial abundance, was positively associated with increased soil organic matter. These positive effects were more pronounced in experiments with long duration (> 1 yr), field soil conditions, and soil pH > 7. IC improves several crop productivity metrics, which could augment sustainable crop production, particularly when practiced for a long duration and in alkaline soils.