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sur le développement des zones arides et semi-arides

Titre : Profile Distribution Characteristics of Soil Physical and Chemical Properties in Different Vegetation Types in Oasis Desert Transition Zone

Auteur : 金彦龙

Grade : Master 2022

Université : Tarim University

Résumé partiel
The Oasis-Desert Ecotone is located between Oasis and Desert,which is an ecologically vulnerable zone with sensitive degradation trend and also the key region threatening the stability of oasis.This study mainly focuses on the Tarim Oasis Desert Transition Zone.Through the field investigation,collected seven different types of natural vegetation including Shrubs-Herbs,Arbor-Herbs,Arbor-Shrubs-Suaeda glauca Bunge Shrubs,Shrubs-Dry poplar,Arbor-Shrub-Herbs and Arbor,five soil profiles were taken at random around the sampling point in each vegetation type,and one soil layer was mixed in each of the five profiles at a depth of 0-100 cm.Therefore,the physical and chemical properties of soil samples in each vegetation type were determined,taking the mean value according to the soil physical properties of each vegetation type.The chemical properties were measured by mixed soil samples from the profile.The correlation and change trend of soil physical and chemical properties under seven different vegetation types were analyzed,and the differences and relationships among vegetation types,soil water and salt,physical and chemical properties were discussed.Finally,this study has concluded the following conclusions :（1）Under the seven vegetation types in the oasis desert transition zone,the species richness is the best under the Tree-Shrub-Herb vegetation type,and the shrub vegetation type has the best adaptability in the whole transition zone.The soil physical properties of different vegetation types have different distribution in different soil layers.The average soil bulk density of Shrub-Herb vegetation type is 1.51 g/kg,and the soil is the most dense compared with the other six vegetation types.The total porosity and capillary porosity of Shrubs-Dry poplar poplar vegetation type were 53.34 % and 47.29 %,and the soil is also the most porous and permeability compared with the other six vegetation types.The soil within 0-5cm under all vegetation types shows obvious looseness.The change trend of soil porosity with the increase of soil layer under different vegetation types is similar to that of soil bulk density.The soil bulk density is significantly negative correlation with the total soil porosity under seven vegetation types（P＜0.01）。（2）The soil chemical characteristics of different vegetation types are as follows : under various vegetation types,the whole performance is that there is a correlation between soil total salt,soil p H and electrical conductivity,the correlation between soil organic matter and total nitrogen is obvious,but not with total phosphorus.The soil chemical influencing factors are different with different soil depths.It is found that under the vegetation type with tree Populus euphratica growth,The soil nitrogen content was significantly higher than that of other vegetation types without tree Populus euphratica growth.The vegetation type with arbor shows that the soil organic matter increases with the augmented of soil depth.There is a very significant positive correlation between the total salt content of soil and the conductivity of soil solution under the seven vegetation types,in which the correlation coefficient of arbor-shrub-Suaeda salsa vegetation type is 0.56,and the correlation number of the other six vegetation types is greater than 0.95,indicating that Suaeda salsa will affect the soil salt content and have a great impact on the total salt and conductivity of soil,Under the vegetation type without Suaeda salsa,the maximum soil water holding capacity and non-capillary water holding capacity showed a very significant positive correlation level（P＜0.01）.

Mots clés : transition zone ;water and salt distribution ;oasis desert ;vegetation type ;soil profile ;

Présentation (CNKI)