Microbial detritus contributes substantially to the soil organic matter (SOM). Analysis of global literature indicated that microbial detritus carbon (C) contributed 59 and 64% of total soil C in arable agricultural and grassland systems respectively, with a 2.5% greater contribution of bacterial-derived detritus in grasslands and with no difference in the proportional contribution of fungal detritus. Total soil C and nitrogen (N) content was higher in grasslands with an average of 2.8 and 1.6 g N kg⁻¹ soil and 28.8 and 16.8 g C kg⁻¹ soil in grassland and arable systems, respectively. Soil N content explained 11 to 28% of the variance in microbial detritus contribution to soil C. Further, total soil N and C content explained more variance than other factors which are commonly considered to mediate SOM content including precipitation, acidity and clay. Microbial biomass C assimilation and re-metabolism of SOM are affected by nutrient supply and the dissimilarity of the C to N, phosphorus (P) and sulfur (S) ratios between fresh organic matter (FOM), SOM and microorganisms (C:N:P:S 10,000:261:32:48, 10,000:833:200:143, and 10,000:1,494:458:154, respectively). In agricultural systems, stoichiometrically balanced nutrient addition to FOM can increase C transfer to SOM by 6 to 52% and importantly reduce the mineralization of pre-existing SOM by 24 to 50%. Future research to quantify economic and environmental implications is warranted with need for a paradigm shift in thinking to focus on the nutrient requirements of the whole soil–plant system rather than the agronomic requirements of crops alone.

中文翻译：

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微生物和养分化学计量作为土壤有机质动力学的媒介

微生物碎屑对土壤有机质（SOM）有很大贡献。全球文献分析表明，微生物碎屑碳（C）在可耕农业和草地系统中分别贡献了土壤碳总量的59％和64％，而草地上细菌衍生的碎屑贡献了2.5％以上，比例贡献没有差异真菌碎屑。草地的土壤总C和氮（N）含量较高，平均土壤N和2.8到1.6 g N kg ^-1，草地C和平均C到28.8和16.8 g C ^-1草地和耕作系统中的土壤。土壤N含量解释了微生物碎屑对土壤C贡献的11％到28％的变化。此外，土壤N和C的总含量比其他通常认为介导SOM含量的因素（包括降水，酸度和黏土）解释的变化更大。养分供应以及新鲜有机质（FOM），SOM和微生物之间C与N，磷（P）和硫（S）的比率的不相似性会影响微生物的碳同化和SOM的再代谢（C：N： P：S 10,000：261：32：48、10,000：833：200：143和10,000：1,494：458：154）。在农业系统中，向FOM添加化学计量平衡的养分可以使C向SOM的碳转移增加6％至52％，并且重要的是将先前存在的SOM的矿化减少24％至50％。