Grazing alters sandy soil greenhouse gas emissions in a sand-binding area of the Hobq Desert,China  

作　　者：WANG Bo LI Yuwei BAO Yuhai 

机构地区：[1]College of Geographical Science,Inner Mongolia Normal University,Hohhot 010010,China

出　　处：《Journal of Arid Land》2022年第5期576-588,共13页干旱区科学（英文版）

基　　金：supported by the Inner Mongolia Science and Technology Project of China(2022YFDZ0027);the Mongolia Basic Geographical Factors and Land Use/Cover Survey of China(2017FY101301-4)。

摘　　要：Deserts are sensitive to environmental changes caused by human interference and are prone to degradation.Revegetation can promote the reversal of desertification and the subsequent formation of fixed sand.However,the effects of grazing,which can cause the ground-surface conditions of fixed sand to further deteriorate and result in re-desertification,on the greenhouse gas(GHG)fluxes from soils remain unknown.Herein,we investigated GHG fluxes in the Hobq Desert,Inner Mongolia Autonomous Region of China,at the mobile(desertified),fixed(vegetated),and grazed(re-desertified)sites from January 2018 to December 2019.We analyzed the response mechanism of GHG fluxes to micrometeorological factors and the variation in global warming potential(GWP).CO_(2)was emitted at an average rate of 4.2,3.7,and 1.1 mmol/(m^(2)•h)and N_(2)O was emitted at an average rate of 0.19,0.15,and 0.09μmol/(m^(2)•h)at the grazed,fixed,and mobile sites,respectively.Mean CH_(4) consumption was as follows:fixed site(2.9μmol/(m^(2)•h))>grazed site(2.7μmol/(m^(2)•h))>mobile site(1.1μmol/(m^(2)•h)).GHG fluxes varied seasonally,and soil temperature(10 cm)and soil water content(30 cm)were the key micrometeorological factors affecting the fluxes.The changes in the plant and soil characteristics caused by grazing resulted in increased soil CO_(2)and N_(2)O emissions and decreased CH_(4) absorption.Grazing also significantly increased the GWP of the soil(P<0.05).This study demonstrates that grazing on revegetated sandy soil can cause re-desertification and significantly increase soil carbon and nitrogen leakage.These findings could be used to formulate informed policies on the management and utilization of desert ecosystems.

关 键 词：GRAZING REVEGETATION re-desertification greenhouse gases global warming potential Hobq Desert 

分 类 号：P467[天文地球—大气科学及气象学] X144[环境科学与工程—环境科学]