Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Effect of Shrub on Soil Organic Carbon Stability of Grassland in Arid Area

Auteur : 张宇

Grade : Master 2022

Université : Xinjiang Agricultural University

Résumé partiel
The stability of soil organic carbon（SOC）refers to the resistance of SOC to external interference in a certain environment,which determines the carbon cycle and turnover.Shrubbery refers to the significant increase of shrub coverage,density and biomass in grassland,which is particularly common in arid areas.The study of the impact of shrub on the stability of grassland SOC in arid areas is of great significance to understand the global carbon cycle,climate change and the relationship between them.In this study,four types of grassland distributed along the altitude were selected in the Middle East section of the northern slope of Tianshan Mountain in typical arid area of Xinjiang.Samples were taken under and between shrub patches respectively.Thermal analysis technology,soil aggregate separation technology and nuclear magnetic resonance spectroscopy technology were used to comprehensively reveal the impact of shrub on the SOC stability of grassland in dry and arid area.The main results are as follows :（1）From temperate desert to mountain meadow,the contents of SOC,soil total nitrogen and total phosphorus increased,while p H and C/N ratio decreased with the increase of altitude.In temperate desert,the total phosphorus of soil under shrub was significantly lower than that between shrubs,but there was no significant difference in SOC,p H,soil total nitrogen and C/N ratio ;In temperate grassland desertification,the soil total nitrogen under shrub was significantly lower than that between shrubs,while the C/N ratio was significantly higher than that between shrubs.There was no significant difference in SOC,p H and soil total phosphorus ;In temperate desert grassland,SOC,C/N ratio,soil total nitrogen and total phosphorus under shrub were significantly higher than those between shrubs,but there was no significant difference in p H ;In mountain meadow,SOC and soil total nitrogen under shrub were significantly higher than those between shrubs,but there was no significant difference in p H,soil total phosphorus and C/N ratio.（2）The proportion of aromatic carbon（C）among shrubs decreased gradually from temperate desert to mountain meadow along the altitude.In temperate desert,temperate grassland desert,temperate desert grassland and mountain meadow,the ratio of alkyl C to alkoxy C increased by 0.07,0.12,0.03 and 0.20respectively.

Mots clés : Grassland ;Altitude;Shrubbery ;Stability of Soil Organic Carbon ;Solid State 13C NMR Technology ;Thermal Analysis Technology ;

Présentation (CNKI)