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Beijing Forestry University (2020)

Soil Moisture Dynamics and Its Mechanism of Artemisia Ordosica Community in Mu Us Sandy Land


Titre : Soil Moisture Dynamics and Its Mechanism of Artemisia Ordosica Community in Mu Us Sandy Land

Auteur : 梁香寒;

Grade : Doctoral Dissertation 2020

Université : Beijing Forestry University

Résumé partiel
As a global problem,desertification has seriously affected the sustainable development of Northwest,Northeast and North China.Therefore,the study of hydrology and water resources is a key and hot issue in desert ecosystem,and soil water is playing a key role in this issue.Driven by soil water,the succession of Artemisia Ordosica community in Mu Us sandy land undergoes a cyclic process:bare sandy land shifting sandy land(pioneer species stage)→semi-fixed sandy land(sparse stage)→fixed sandy land→fixed sandy land degradation stage→bare sandy land(or mobile sandy land).Previous studies focused on surface soil water content and shallow soil infiltration under simulated rainfall conditions,but they lacked real-time,long-term and continuous monitoring of soil water.Based on the existing research,this study used automatic monitoring system to monitor the precipitation and soil water in the study area continuously and quantitatively.Field investigation and field measurement were carried out.Combined with the root distribution of dominant species in the area,different types of sandy land(fixed sandy land,semi-fixed sandy land and shifting sandy land)in the study area were systematically analyzed.Distribution and dynamics of soil water in fixed sandy land and mobile sandy land,the response of soil water in different sandy land to natural rainfall,the factors affecting soil water change,the difference of rainfall recharge to soil water in different sandy land,the relationship of water balance and the proportion of soil water transformation in different sandy land were estimated and explored.Discuss the vegetation stability of sand consolidation and the vegetation carrying capacity of soil water.This study is helpful to reveal the characteristics of water change and water balance mechanism under rainfall and drought conditions.It has important theoretical and practical significance for further understanding the succession of vegetation communities in Maowusu sandy land,and can provide scientific basis for rational allocation of vegetation,vegetation restoration and reconstruction in arid and semi-arid sandy areasCompared with the traditional fixed-time and fixed-point soil moisture monitoring system,EC-5 soil moisture monitoring system,which is the latest monitoring method,can be used to monitor soil moisture for a long time and on a large scale,which ensures the quantity and continuity of data and better reflects soil moisture dynamics,precipitation infiltration and soil water balance.Condition.Compared with the traditional soil moisture dynamic analysis,the study period was divided into different periods by the standardized precipitation index method.In each period,the classical statistics and geostatistics were used to analyze the internal relationship between the spatial and temporal variability of soil moisture,and the main environmental factors were pre-sorted through RDA analysis.The factors affecting the spatial and temporal dynamics of soil moisture in different periods were analyzed.Then the contribution of the main controlling factors to soil moisture change was studied by quantitative separation of environmental factors

Mots clés : Soil moisture; Mu Us sandy land; Desertification; Combating;

Présentation (CNKI)

Page publiée le 3 juin 2021