Desertification reversion alters soil greenhouse gas emissions in the eastern Hobq Desert, China

摘要

Deserts cover more than 41% of the world's total land area and are significant in the terrestrial carbon cycle. The impact of desertification reversion and revegetation on the physical and chemical properties of soil is well studied; however, this study seeks to further the understanding of how they impact the flux of greenhouse gases (GHGs). Three sandy sites of different desertification reversal stages in the Hobq Desert were selected. Variations in the characteristics of GHG flux and its response mechanism to environmental hydrothermal conditions and soil properties were analyzed. Higher soil carbon dioxide (CO2) emissions were observed in the growing season, whereas nitrous oxide (N2O) emissions were mainly observed in the non-growing season. Methane (CH4) absorption showed no obvious seasonal change. Linear regression analysis revealed that GHGs in the study area were positively correlated with total nitrogen and organic carbon content, and the number of microorganisms present in the soil. Hydrothermal factors were critical controllers of soil CO2 emissions, but they did not majorly influence CH4 and N2O fluxes. The results illustrate the importance of desertification reversal and revegetation in mitigating climate change, and that deserts have a significant role in the global carbon cycle.