Impact of the Rhizosphere on Soil and Microbial Stoichiometry across Global Agroecosystems

The stoichiometry of the rhizosphere, specifically regarding carbon (C), nitrogen (N), and phosphorus (P), indicates the balance between nutrient mineralization and retention during organic matter decomposition. However, the extent and underlying mechanisms of rhizospheric effects on soil and microbial stoichiometry remain inadequately quantified on a global scale across various agroecosystems. 882 individual cases from 113 targeted literature sources were integrated and analyzed in a meta-analysis to assess the rhizosphere on soil and microbial stoichiometry. Additional information gathered encompassed latitude, longitude, climate, plant properties, soil properties, microbial properties, and experimental conditions.The rhizosphere significantly increases soil C:N, C:P, and N:P ratios while decreasing e microbial C:N, C:P, and N:P ratios compared to bulk soil. Notably, the rhizospheric effects on soil C:N increase in humid regions and decrease in arid zones, whereas the impact on microbial C:N shows an increasing trend with higher soil organic C and ammonium N levels. Sensitive crops such as maize and vegetables enhance the rhizospheric soil C:N ratio by 5.68% and 8.91% respectively, and reduce the microbial C:N ratio by 11.00% and 19.44%. Soil organic C and ammonium N are identified as critical drivers of the rhizospheric soil and microbial C:N ratios, with relative influences of 37.9% and 30.3%, respectively. The studies establish a coupling relationship between rhizospheric soil and microbial stoichiometry and provide valuable insights into rhizospheric soil and microbial nutrient cycling, contributing to soil health and efficient nutrient utilization through targeted regulatory measures.