Response of Soil Microbial Residue Accumulation in Paddy Soil to Straw Amendment:A Review
Carbon cycling in paddy soil is a crucial aspect of China's terrestrial ecosystem carbon cycle.Promoting the sequestration and stabilization of soil organic carbon in paddy ecosystem plays a critical role in mitigating global climate change.Soil microorganisms are the primary drivers of carbon cycling.There is an increasing recognition of the critical role of microbial residues/necromass in long-term carbon sequestration and stabilization in soil.However,there are fewer investigations on how exogenous organic matter inputs,such as crop straw amendment,affect the accumulation dynamics of microbial necromass in paddy soils compared to those conducted on dryland soils.Additionally,there is a lack of systematic understanding of the process and mechanism by which microbes participate in soil carbon sequestration via microbial necromass production and accumulation in paddy ecosystem.Therefore,this review firstly introduces the importance of microbial residues in the formation and accumulation of soil organic carbon pools using amino sugar biomarkers.Then,it elaborates on the responsive dynamics and stocks of microbial necromass following rice straw amendment,as well as the incorporation of straw-carbon into microbial amino sugars in rice paddy soils.And it also analyzes the main climatic and edaphic factors controlling the transformation of microbial-derived carbon accumulation.Finally,it proposes that advanced spectroscopy and high-resolution imaging technology should be used in combination with isotope tracing to conduct more in-depth research on necromass stabilization mechanisms in future studies.