Grazing exclusion promotes soil organic carbon accumulation in Tibetan grasslands with lower temperatures  

作　　者：Guangru Zhang Xiangping Tan Jinhong He Dengnan Luo Xiang Zeng Minqi Liang Ruochen Cao Siyuan Peng Pan Li Long Tao Muhammed Mustapha Ibrahim Zhongmin Hu 

机构地区：[1]School of Geography,South China Normal University,Guangzhou 510631,China [2]Guangdong Provincial Key Laboratory of Applied Botany,South China Botanical Garden,Chinese Academy of Sciences,723 Xingke Rd.,Tianhe District,Guangzhou 510650,China [3]Guangzhou Institute of Forestry and Landscape Architecture,Guangzhou Urban Ecosystem National Field Station,Guangzhou 510405,China [4]Facility of Geographical Science,Beijing Normal University,Beijing 100875,China [5]College of Arts and Sciences,Beijing Normal University at Zhuhai,Zhuhai 519087,China [6]School of Atmospheric Sciences,Guangdong Province Data Center of Terrestrial and Marine Ecosystems Carbon Cycle,Sun Yat-Sen University,Zhuhai 510245,China [7]International Institute for Earth System Sciences,Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application,Nanjing University,Nanjing 210023,China [8]Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology,Key Laboratory for Land Satellite Remote Sensing Applications of Ministry of Natural Resources,School of Geography and Ocean Science,Nanjing University,Nanjing 210023,China [9]Hainan Baoting Tropical Rainforest Ecosystem Observation and Research Station,School of Ecology,Hainan University,58 Renmin Avenue,Haikou 570228,China

出　　处：《Ecological Processes》2024年第4期254-264,共11页生态过程(英文)

基　　金：supported by the Second Tibetan Plateau Scientifc Expedition and Research Program(2019QZKK0405);National Natural Science Foundation of China(U23A2002,32271725);Collaborative Innovation Program of Hainan University(XTCX2022STB07);start-up fund of Hainan University(KYQD(ZR)21096).

摘　　要：Background Grazing exclusion is a practical approach to restore vegetation in degraded grasslands and enhance soil organic carbon(SOC)sequestration.However,the dynamics and drivers of SOC in grasslands after grazing exclusion have not been well documented,especially in ecosystems with cold climates.Methods Here,we established 14 paired treatments(grazing exclusion vs.free-grazing)along a 600-km transect in the northeastern zone of the Qinghai-Tibet Plateau.After six years,we analyzed vegetation biomass dynamics and measured the soil physicochemical properties and organic C concentration across three depths(0–10,10–20,and 20–30 cm).Results Grazing exclusion signifcantly increased above-and belowground biomass(139.85%and 43.30%,respectively),pH(1.38%),total phosphorus(3.29%),nitrate nitrogen(18.03%),and ammonium nitrogen(17.81%),but signifcantly decreased soil bulk density(2.43%)and clay content(10.49%),particularly in 0–30 cm.Specifcally,SOC concentrations positively responded to grazing exclusion(0–10 cm)in 9 of the 14 sites evaluated.The efects of grazing exclusion on SOC concentrations were signifcantly higher in areas with a mean annual temperature(MAT)below 0℃ compared to those in sites with a high MAT(>0℃).The SOC concentrations signifcantly correlated with the mean annual precipitation(MAP)in both treatments,but these correlations diminished with increasing soil depth.Ridge regression analysis showed that soil chemical properties(e.g.,total nitrogen and phosphorus)positively infuenced SOC accumulation,while MAT negatively infuenced it after grazing exclusion.Path analysis further revealed that MAT indirectly regulated SOC dynamics via soil chemical properties.Conclusions Our study highlights that grazing exclusion results in an asynchronous SOC and plant biomass accumulation and may be more benefcial for SOC sequestration in Qinghai-Tibet Plateau grasslands with lower temperatures.Also,humid climates promote SOC concentration in alpine grasslands.These results could help develop management pra

关 键 词：Grazing exclusion Plant biomass Qinghai-Tibet Plateau Soil carbon storage Soil physicochemical property 

分 类 号：S812.2[农业科学—草业科学] X144[农业科学—畜牧学]