The vertical distribution and control of microbial necromass carbon in forest soils

• DOI: 10.1111/geb.13159
• Publication Date: 2020-07-29T03:40:48Z
• Authors: Xiangyin Ni; Shu Liao; Siyi Tan; Yan Peng; Dingyi Wang; Kai Yue; Fuzhong Wu; Yusheng Yang
• Keywords: Soil carbon; Subsoil; Topsoil; Soil horizon

Abstract Aim Forest soils contain large amounts of terrestrial organic carbon (C), but the formation pathway soil C (SOC) remains unclear. Recent evidence suggests that microbial necromass is a significant source SOC, yet global quantitative assessment across whole profile lacking. We aimed to assess vertical distribution and control microbial‐derived SOC in forest soils. Location Global forests. Time period 1996–2019. Major taxa studied Soil carbon. Methods evaluated proportions fungal bacterial total litter layer, O horizon soil, various depths mineral forests using biomarker (glucosamine muramic acid) data. Results The increased significantly with depth, ranging from 30% 62% below 50 cm. However, only followed this increasing trend depth; showed little variation profile. Higher was observed lower C/N ratios smaller aggregate sizes. ratio biomass dominantly determined surface (above 20 cm), clay content primary factor subsoil (below cm). Main conclusions Microbial accounted for high percentages (particularly at >20 its long‐term stabilization may be governed by different mechanisms horizons. Substrate quality regulates activity then controls turnover while occlusion facilitates protection subsoil. These differential could applied Earth system studies predicting dynamics