Microbial ecological clusters structured by environments drive maize residue decomposition at the continental scale

Area of Science:

• Soil Science
• Microbiology
• Ecology

Background:

• Environmental factors like climate and soil properties indirectly control residue decomposition by influencing microbial communities.
• Microbial ecological clusters (eco-clusters), structured by environmental factors, impact ecosystem functions, but their role in residue decomposition across large geographic areas is not well understood.

Purpose of the Study:

• To investigate the continental patterns of maize residue-derived carbon dioxide (RDC) across a latitudinal gradient.
• To determine if and how microbial eco-clusters drive and predict RDC.
• To create a continental atlas of RDC in upland and paddy fields.

Main Methods:

• Collected agricultural soils from paired upland and paddy fields along a latitudinal gradient.
• Conducted a microcosm experiment using 13C-labeled maize residue.
• Identified microbial eco-clusters based on microbial environmental preferences and analyzed their relationship with RDC.

Main Results:

• RDC decreased with increasing latitude in both soil types.
• Identified 21 microbial eco-clusters that explained 51.15% of the spatial variation in RDC.
• Eco-clusters associated with high precipitation, high temperature, low pH, and low nutrients positively affected RDC. Upland soils exhibited 2.40-fold higher RDC than paddy soils. Low-pH and high-organic matter eco-clusters were key predictors in upland and paddy fields, respectively.

Conclusions:

• Historically shaped microbial eco-clusters are significant drivers and predictors of residue decomposition.
• Environmental factors indirectly regulate residue decomposition through microbial eco-clusters.
• The study provides a continental-scale understanding of residue decomposition patterns and the role of microbial communities.