A 40 % paddy surface soil organic carbon increase after 5-year no-tillage is linked with shifts in soil bacterial composition and functions

Jian-Ying Qi , Xiang-Bin Yao , Jian Lu Long-Xin He, Jun-Li Cao, Zheng-Rong Kan, Xing Wang, Sheng-Gang Pan , Xiang-Ru Tang

The Science of the total environment

DOI:10.1016/j.scitotenv.2022.160206

摘要

Soil organic carbon (SOC) is related to soil fertility, crop yield, and climate change mitigation. Paddy soil is a significant carbon (C) sink, but its C sequestration potential has not been realized as the various driving factors are still not fully understood. We performed a 5-year paddy field experiment in southern China to estimate tillage effects on SOC accumulation and its relation with soil bacteria. Soil C input from rice residue, SOC content, CO2 flux, soil bacterial community composition, and predicted functions were analyzed. No-tillage (NT) increased (P < 0.05) rice residue C inputs (by 12.6 %-15.9 %), SOC (by 40 % at the surface soil layer compared with CT), and CO2 fluxes compared with conventional practices (RT and CT). Also, NT significantly altered the soil bacterial community. The random forest model showed that the predicted bacterial functions of Degradation/Utilization/Assimilation Other, C1 Compound Assimilation, and Amin and Polyamine Degradation were the most important functions associated with SOC accumulation. Analysis of metabolic-pathway-differences indicated that NT significantly decreased the BENZCOA-PWY (anaerobic aromatic compound degradation) and the AST-PWY (L-arginine degradation II). Therefore, the rapid paddy SOC increase is associated with both residue C input (from higher rice yields) and the degradation functions regulated by soil bacteria.