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sur le développement des zones arides et semi-arides

Titre : Effects of Manipulated Precipitation on Soil Organic Carbon and Its Stability in Desert Steppe of Western Loess Plateau

Auteur : 蒿廉伊

Grade : Master 2022

Université : Northwest Normal University

Résumé partiel
Precipitation pattern change is one of the main manifestations of global change.How precipitation change affects the stability of soil carbon pool is a key link in the study of terrestrial ecosystem carbon cycle.Soil organic carbon and its components are important indexes reflecting the dynamic changes of soil organic carbon pool and have a very important influence on the stability of soil organic carbon pool.The desert steppe in the west of loess Plateau is located in semi-arid region,where precipitation is scarce and vegetation is sparse.The ecosystem is very fragile,which plays an important role in maintaining the stability of regional ecosystem.However,the effect and mechanism of precipitation change on the stability of carbon pools in this region are not clear.Therefore,the study on the impact of precipitation change on soil organic carbon components and its stability in this region is of great significance to accurately assess the response of soil carbon sink potential to global change,and is also a positive response to the national policy of "carbon peak and carbon neutralization".In this study,five precipitation gradients（40% reduction,20% reduction,control,20% increase and 40% increase）were set up in a field controlled precipitation experiment on the western desert steppe of the Loess Plateau.Analysis methods such as variance analysis,correlation analysis and structural equation model were used to reveal the change rules of enzyme activities,organic carbon components and stability of organic carbon in desert steppe under precipitation change,and further explore the mechanism of influencing stability of organic carbon.The main results are as follows :（1）Precipitation treatment had significant effects on catalase,sucrase,urease and GME activity in 0-5cm soil layer,and the GME activity in 0-10 cm soil layer and5-10 cm soil layer were significantly lowest under +20% treatment,and catalase activity under-20% treatment was significantly lower than that under-40% treatment.In addition,the geometric mean values of urease,sucrase,neutral phosphatase and soil enzyme activities under precipitation treatment decreased with the increase of soil depth.In conclusion,precipitation treatment had a significant effect on the enzyme activity in 0-10 cm soil layer,and the enzyme activity decreased with the increase of soil depth under precipitation treatmen

Mots clés : Precipitation changes ;Desert steppe ;Soil enzyme activity ;Soil organic carbon components ;Stability of soil organic carbon ;

Présentation (CNKI)