Changes in plant, soil and microbes in a typical steppe from simulated grazing: explaining potential change in soil carbon

Grazing can directly or indirectly influence carbon (C) inputs, turnover, and retention in grassland soil. However, relative to the plant response to grazing, belowground biota and process responses are more complex and often do not correlate with the aboveground responses. Ungulate grazing involves three mechanisms - defoliation (removal of plant shoot tissue), dung and urine return, and trampling. An evaluation of the relative roles of these mechanisms and their combinations in grazing can explain the causes of changes in grassland, thereby explaining the soil carbon sequestration in a steppe ecosystem. In this study, we examined the changes in plants attributes, soil abiotic characteristics, and the soil microbial community in response to mowing (M), dung and urine addition (DU), simulated trampling (T), and their combinations by conducting a 3-year experiment in a steppe ecosystem in Inner Mongolia, China. Most of the variation in the grazing effects on grassland was explained by de...