Title: Grazing season alters soil respiration in a semiarid grassland on the Loess Plateau

Authors: Zhen Wang, Xiuli Wan, Mei Tian, Xiaoyan Wang, Junbo Chen, Xianjiang Chen, Shenghua Chang, Fujiang Hou*

Journal: Nutrient Cycling in Agroecosystems

Impact Factor: IF₂₀₁₉=2.45 (农林科学二区)

Abstract: Although the effects of grazing on soil respiration are well understood, there is still a lack of understanding about the mechanisms underlying the effects of grazing intensity on soil respiration. In addition, the response of soil respiration to the grazing season, such as warm- and cold-season grazing, remains unclear. To determine how grazing intensity (no, light grazing, moderate grazing, heavy grazing) and grazing season (warm-season grazing, WG; cold season grazing, CG) affect soil respiration, we conducted soil respiration measurements in two long-term grazed grasslands under CG and WG from 2010 to 2011. Our results showed that light, moderate, and heavy grazing significantly increased soil respiration relative to no grazing in 2010, but grazing intensity had little effect on soil respiration in 2011.With the increase in grazing intensity, soil respiration decreased by 10?17% at the WG site but increased by 23?30% at the CG site. Structural equation modeling

analysis indicated that grazing intensity indirectly affected soil respiration by altering aboveground and soil microbial biomass carbon. CG enhanced soil respiration by 22% relative to WG. Grazing season induced soil moisture, soil temperature, soil microbial biomass carbon and nitrogen could be mechanisms underlying increased soil respiration under in grazed grasslands. Precipitation had a strong correlation with soil respiration. Our results highlight the importance of grazing season altering soil respiration in semiarid grassland ecosystems and indicate that interactive effects of grazing season and precipitation events on soil respiration need to be considered in the future.

链接: https://doi.org/10.1007/s10705-020-10092-8