@misc{WeiWeiRyoetal., author = {Wei, Yuqi and Wei, Bin and Ryo, Masahiro and Bi, Yixian and Sun, Xiangyun and Zhang, Yingjun and Liu, Nan}, title = {Grazing facilitates litter-derived soil organic carbon formation in grasslands by fostering microbial involvement through microenvironment modification}, series = {CATENA}, volume = {232}, journal = {CATENA}, publisher = {Elsevier BV}, issn = {0341-8162}, doi = {10.1016/j.catena.2023.107389}, pages = {9}, abstract = {Grasslands store 10-30 \% of the global soil organic carbon (SOC) and have the potential to mitigate the increase in atmospheric CO2 concentrations. Grazing plays a crucial role in regulating SOC storage in grassland ecosystems. However, the mechanistic understanding of how grazing influences the SOC dynamic still needs to be improved. We investigated how grazing-induced microenvironment changes influence the microbial assimilation of plant litter C and SOC formation from decomposed litter C in a multi-year field experiment, where grazing was simulated with mowing, dung and urine return, and trampling. We incubated 13C labeled litter in PVC collars to trace the microbial assimilation of litter C and the fate of litter C in the SOC after decomposition. While the grazing treatments changed soil properties marginally, mowing decreased above-ground plant biomass, litter mass, plant height, and plant cover (-12 \% to -79 \%). Accordingly, mowing treatment increased the exposure of litter to UV radiation (+38 \%) and therefore facilitated the microbial assimilation of litter C (+20 \%) and the SOC formation (+15 \%). Trampling treatment promoted the transformation of litter C to SOC pools by mixing litter and soil (+34 \%). Dung and urea return treatment did not affect SOC formation due to a marginal change in available nitrogen. Collectively, our results suggest that grazing facilitates litter-derived SOC formation by regulating microbial involvement through changes in the microenvironment. Our study indicates that grazing promotes SOC formation from plant litter, which maintains SOC storage in grasslands. Accurate quantification of the contribution of plant C input to SOC pools in different grasslands under various utilization is the next step to better predict SOC dynamics.}, language = {en} }