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2021

Effects of Precipitation Variation on Soilorganic Catbon Dynamics in Stipa Breviflora Shrub Desert Steppe

朱蔚娜

Titre : Effects of Precipitation Variation on Soilorganic Catbon Dynamics in Stipa Breviflora Shrub Desert Steppe

Auteur : 朱蔚娜

Grade : Master 2021

Université : Inner Mongolia University

Résumé partiel
Precipitation variation is an important part of global climate change.The desert steppe is sensitive to the change of precipitation and the phenomenon of shrub encroachment is common.The formation and stabilization mechanism of soil organic carbon in desert steppe is still unclear due to the complexity of input and output of soil carbon under the combined influence of precipitation change and shrub encroachment.This study took Stipa breviflora shrub desert steppe as the research object,and established an experimental platform to simulate rainfall changes(precipitation decreased by 30%,natural precipitation,precipitation increased by30%,and precipitation increased by 50%).By analyzing the biomolecular composition of different tissues of dominant plants and that of soil organic carbon in Stipa breviflora community under different precipitation treatments,we screened out the biomarkers indicating the input of aboveground and underground organic carbon by plants,and clarified the main sources of plant derived organic carbon in shallow soil under different precipitation treatments.By analyzing the distribution characteristics of soil labile organic carbon,recalcitrant organic carbon and total organic carbon and the degradation degree of plant derived organic carbon in soil under different precipitation treatments,the stability of soil organic carbon in shallow layer was explored,and the effects of precipitation on the formation and stability of soil organic carbon in Stipa breviflora shrub desert steppe were systematically studied.The results can provide a theoretical basis for predicting the potential of soil carbon sequestration in the shrub desert steppe under the background of rainfall change,and also provide a reference for the development of management measures for increasing soil organic carbon sink.The main results were as follows :(1)The plant species composition and plant importat value in Stipa breviflora shrub steppe changed obviously under different precipitation treatments.With the increase of precipitation,the species number of perennial forbs increased gradually,and the important values of Artemisia frigida,Leymus chinensis and Artemisia scoparia increased,while the species number and important values of perennial tupitgrasses decreased gradually,and the important values of Chenopodium aristatum decreased,especially in the shrub patches.(2)The decrease of precipitation significantly reduced the SOC content in the0-10 cm soil layer of herbaceous matrix and the shrub nebkhas,but there was no significant difference in SOC content between the shrub patch and the herbaceous matrix.The content of soil recalcitrant organic carbon was significantly increased under the precipitation plus 50%.

Mots clés : precipitation changes ;Stipa breviflora shrub desert steppe ;plant biomarker ;soil organic carbon stability ;

Présentation (CNKI)

Page publiée le 27 octobre 2021