Straw Application and Soil Microbial Biomass Carbon Change: A Meta-Analysis

Soil microbial biomass carbon (MBC) can reveal the total microbial count, and microbial community diversity can be investigated using the Shannon index. Straw application is an important factor affecting soil MBC. Many studies have found that straw application increases soil MBC, although some studies suggest that straw application decreases soil MBC. This discrepancy underscores the need for a meta-analysis. A global dataset is established from 47 studies, compiling a total of 71 individual datasets. The results reveal that in tropical and temperate zones, the addition of maize, rice, and wheat straw causes a significant improvement in MBC content, although it has no effect on microbial community diversity. The research also indicates that MBC does not increase with the addition of straw of >10 Mg ha(-1); therefore, the amount of straw and nitrogen-phosphorus-potassium (NPK) fertilizer used should be appropriate. According to the analysis, the optimum usage is 10 Mg ha(-1). The best fertilization method consists of analyzing the soil fertility first and then adding NPK fertilizer appropriately according to the type and composition of straw application.