Researchers from the Chinese Academy of Agricultural Sciences (CAAS) have uncovered how nitrogen fertilization enhances the decomposition of crop straw in fields, revealing a crucial role played by unexpected microbial players.

The study, led by the Plant Nutrition Team at CAAS's Institute of Agricultural Resources and Regional Planning, found that nitrogen fertilizer application induces the formation of a microbial community dominated by Bacillus decomposers and copiotrophic non-decomposers (primarily Staphylococcus). Intriguingly, while the Staphylococcus bacteria themselves lack decomposition capability, they drive a significant increase in the proportion of highly efficient Bacillus decomposers through a mechanism of sugar competition. This interaction maintains the community's high degradation capacity.

This microbial restructuring boosts the straw decomposition rate under nitrogen fertilization by 17% compared to scenarios without this dynamic.

Background and Challenge:

Crop straw has a high carbon-to-nitrogen (C:N) ratio. When returned to the soil, nitrogen fertilizer is typically added alongside it. This practice aims to accelerate decomposition and prevent microbes from competing with crops for essential nitrogen. However, the specific microbial processes governing straw decomposition under nitrogen application remained poorly understood.