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sur le développement des zones arides et semi-arides

Titre : Physicochemical Properties of Typical Patch Vegetation Root Zone Soil and Its Influencing Factors in Desert-Oasis Ecotone

Auteur : 邓丽媛

Grade : Master 2022

Université : Lanzhou Jiaotong University

Résumé partiel
The plant coverage in the desert-oasis ecotone is about 20%-25%,and the anti-interference ability of the ecological environment is relatively weak.Any disturbance event may lead to major changes in major species and community patches.The transition zone After the ecological environment is destroyed,it is difficult to restore it to its original state.The desert-oasis transition zone in Linze County is an ideal place to study the patchy vegetation and its root zone soil in the desert-oasis transition zone due to its special climatic conditions and geographical location.Therefore,this paper takes the desert-oasis ecotone in the middle reaches of the Heihe River as the research area,and collected samples of three types of sand-fixing plants,Haloxylon ammodendron,Calligonum mongolicum and Nitraria sphaerocarpa in different slope aspects（Windward and leeward slopes）,different horizontal distances（0-0.5cm and 1.5-2.0cm）,and different soil layers（0-120cm）in the root zone from 2020 to 2021.Depth soil samples were used to analyze the physical and chemical properties of soil in the root zone of sand-fixing plants,and various influencing factors（plant species,atmospheric temperature,precipitation,wind speed,slope aspect,soil temperature）were analyzed by Pearson correlation analysis and grey correlation analysis.The interrelationship with soil physical and chemical properties aims to provide theoretical basis and scientific support for the rational co nstruction and sustainable development of vegetation in the desert-oasis ecotone,as well as vegetation restoration and protection and reconstruction.study meaning.The main findings are as follows :（1）The content of coarse sand in the root zone of the three sand fixing plants is very little,and there is basically no coarse sand in the depth of 40-120 cm in the root zone of Calligonum mongolicum ;The content of fine sand and medium sand（32.545%）in the root zone of the three sand fixing plants is basically less than that of super fine sand（63.521%）.（2）In general,the soil porosity in the root zone of the three types of sand-fixing plants first decreased and then increased with the increase of soil depth ;soil bulk density,electrical conductivity,and organic matter first increased and then decreased with the increase of soil depth.The soil moisture content,total nitrogen and total phosphorus decreased with the increase of soil depth ;p H increased with the increase of soil depth.Except for individual soil layers,the variability of soil porosity,p H,organic matter,total nitrogen and total phosphorus in the 0-120 cm soil layer in the root zone of three types of sand-fixing plants decreased with the increase of soil depth ;The variability of soil bulk density first decreased and then increased with the increase of soil depth ;The variability of water content in the root zone of Calligonum mongolicum and Nitraria sphaerocarpa decreased with the increase of soil depth,while that of Haloxylon ammodendron was the opposite ;The variability of soil conductivity in the root zone of Haloxylon ammodendron and Calligonum mongolicum increased with the increase of soil depth,while that of Nitraria sphaerocarpa was the opposite.

Mots clés : Desert-oasis ecotone ;Soil physical and chemical properties ;Correlation;Influencing factors ;Grey correlation analysis ;

Présentation (CNKI)