The Innovation Team of Grassland Ecology and Remote Sensing at the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS) has made significant progress in elucidating the response and regulation mechanisms of soil respiration and its components to continuous mowing. The relevant findings have been published in the journals Ecological Processes and China Agricultural Information.

Mowing, as one of the primary utilization methods in grassland ecosystems, leads to the direct removal of aboveground plant parts, resulting in losses of photosynthetic carbon and ecosystem nutrients, thereby affecting carbon emissions in grassland ecosystems. Soil respiration, as the second largest carbon flux in terrestrial ecosystems, exerts a profound impact on the carbon cycling processes in terrestrial ecosystems. While many studies have shown that mowing can alter soil respiration in grassland ecosystems, it is still unclear whether the effects of continuous mowing on autotrophic and heterotrophic respiration in soil respiration are consistent and whether the proportions of the two have changed.

Based on a four-year continuous mowing experimental site, the study monitored carbon emissions from autotrophic and heterotrophic respiration in the soil. It was found that continuous mowing suppresses plant biomass and microbial activity, reduces total soil respiration, and its inhibitory effect on soil respiration has an annual cumulative effect. At the same time, continuous mowing can promote the allocation of plant photosynthetic carbon underground, thereby increasing the proportion of soil autotrophic respiration from plant roots and reducing the contribution rate of carbon emissions from microbial heterotrophic respiration. These results suggest that managing grassland ecosystems through harvesting practices can mitigate the trend of rising global carbon dioxide concentrations due to climate change, but the nutrient loss and decrease in grassland productivity caused by continuous mowing need to be considered. Future grassland management should reevaluate this utilization method to ensure sustainable use. 

Zhu Wen, a master's graduate from the IARRP, is the first author of the paper, with researchers Liu Weixing and Shao Changliang serving as corresponding authors. This research was supported by the National Key Laboratory of Efficient Utilization of Northern Arid and Semiarid Cropland and the National Natural Science Foundation of China.

Citation and Original Link:

Zhu, W., Legesse, T.G., Dong, X., Li, A., Shi, Z., Tong, Q., Shao, C., Liu, W., 2024. Consecutive annual mowing reduces soil respiration and increases the proportion of autotrophic component in a meadow steppe. Ecological Processes 13 (75). https://doi.org/10.1186/s13717-024-00537-1