Maize growth as a function of cover crop-mediated soil microbiome

Soil microbes are critical drivers of maize growth and soil health by regulating soil fertility and suppressing diseases. Yet, the relative contribution to maize growth across diverse soil types, particularly following cover crop management, remains virtually unknown. Such knowledge is pivotal for soil ecological engineering, as microbiome management is emerging as a highly promising tool for more sustainable agriculture. Here, we collected 27 soils from different regions of China and subjected them to controlled conditions with two cover crop types (legume and gramineae) to investigate the contribution of soil microbes to maize growth. Our study demonstrates the functional importance of soil microbial taxa in explaining the capacity of soils to support maize growth. Soil microbes explained up to 29% of the variation in maize biomass, with key taxa such as Geodermatophilus, Lapillicoccus, and Acidipila bacteria strongly positively correlated with maize biomass. These important linkages remained robust even after accounting for the contribution of geographic, climatic, and soil factors in our analyses. Furthermore, we observed that gramineae cover crops significantly reduced both soil nitrogen availability and maize growth, whereas legume cover crops reduced soil nitrogen availability without impairing maize growth, highlighting the role of agricultural practices in steering microbiome-mediated soil functions. Together, our work highlights the fundamental contribution of soil microbes to explaining maize growth across contrasting soil environments, which is critical to predicting the future of food security in a changing world.