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sur le développement des zones arides et semi-arides

Titre : Effects of Grazing Exclusion on Organic Carbon Storage of Sagebrush Desert Grassland

Auteur : 周凌波

Grade : Master 2022

Université : Xinjiang Agricultural University

Résumé partiel
The sagebrush desert grassland is an important springfall range in Xinjiang,which has been degraded for a long time by overgrazing,and needs to be restored and managed.Grazing exclusion is one of the main measures to control the degradation of sagebrush desert grasslands,the study of the effect of grazing exclusion on the organic carbon content and its storage in sagebrush desert grassland ecosystem is important to understand the restoration of ecological and productive functions of the degraded grassland ecosystem.Therefore,in this paper,the vegetation biomass（above-ground vegetation biomass,litter biomass,underground biomass）and its organic carbon content,0-100 cm soil bulk density and organic carbon content were measured in a paired experimental design in sagebrush desert grasslands in Manas,Hutubi and Qitai counties on the northern slope of Xinjiang Tianshan Mountains to compare the changes of organic carbon content and storage of each component in different sites.The results will reveal the general pattern of the response to grazing exclusion and the interrelationships among the components,with the aim of providing data to support the carbon management of degraded grassland ecosystems and the prediction of their potential.The main results are as follows :（1）The above-ground vegetation biomass,litter biomass,underground biomass from 0-100 cm and total plant biomass of sagebrush desert grassland showed an overall increasing trend after grazing exclusion,and the change trends were consistent across the sites.Compared with the control,the above-ground vegetation biomass and litter biomass of sagebrush desert grassland increased by 127.37%（P＜0.01）and139.00%（P＜0.05）respectively after grazing exclusion,while the overall increase in below-ground biomass from 0-100 cm was not significant.The total biomass of sagebrush desert grassland increased by 40.30%（P＞0.05）after grazing exclusion,while the root-to-crown ratio decreased by 31.24%（P＞0.05）.（2）Grazing exclusion increased the organic carbon content of vegetation and its storage in sagebrush desert grassland,and the organic carbon content and storage of above-ground vegetation and organic carbon storage of litter matter increased significantly by 18.63%,176.78% and 142.42% on average compared with the control（P＜0.05）,while the organic carbon content of litter matter and organic carbon and storage of 0-100 cm underground biomass did not increase significantly.Except for 0-5 cm and 50-70 cm soils,the organic carbon content of underground biomass and its storage volume in the rest of the soils increased and decreased insignificantly.

Mots clés : grazing exclusion ;sagebrush desert grassland ;organic carbon ;carbon pool composition ratio ;

Présentation (CNKI)