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

Titre : Study on Soil Quality Evaluation and Its Influencing Factors in Desert Grassland Area of Siziwang Banner

Auteur : 曲文静

Grade : Master 2022

Université : Inner Mongolia Normal University

Résumé partiel
The grassland area of Inner Mongolia is an important animal husbandry production and breeding base and natural pasture in China.The desert grassland area of Siziwang Banner is a key area for the ecological construction of two screens and three belts in China.This area is located in an arid and semi-arid climate area with fragile ecological environment.At present,the ecological restoration of degraded grassland has attracted the attention of many scholars and previous local governments,Accurate soil quality assessment of desert grassland is of great significance to the improvement and construction of grassland ecological environment.In this paper,the study area is selected in the desert grassland area of Siziwang Banner.38 sampling points are selected through the systematic grid sampling method to measure the physical,chemical and biological indexes of the desert grassland soil in the study area,and study and analyze its spatial distribution characteristics ;With the help of principal component analysis,minimum data set and comprehensive evaluation method of soil quality,the soil quality evaluation data set of desert grassland is established,and the evaluation index system is established to evaluate the soil quality of desert grassland area ;This paper analyzes the factors affecting soil quality from two aspects of nature and humanity,in order to provide data reference for the establishment of local soil quality evaluation index system and provide theoretical basis for grassland ecological construction and grassland management.The main conclusions are as follows :（1）The spatial variation of main soil chemical indexes in the study area is large.With the deepening of soil layer,the content of organic matter,total nitrogen,available nitrogen,available phosphorus and available potassium gradually decrease,and there is a phenomenon of surface agglomeration.According to the national soil nutrient classification standard,the content of organic matter is at Level 3,the content of total nitrogen is at level 4,the content of available nitrogen is at level 4,the content of available potassium is at level 5 and the content of available phosphorus is at level 4,which is in a relatively deficient and deficient state as a whole.With the deepening of the soil layer,the p H value of the soil increases gradually and is alkaline as a whole ;The spatial variation degree of physical indexes is large.The soil mechanical composition is mainly composed of sand（55.22%-68.13%）,followed by silty sand（30.49%-41.43%）,and clay（1.11%-2.89%）accounts for the least.With the deepening of soil depth,the content of soil clay and silty sand gradually increases,and the content of sand gradually decreases.The study area is mainly affected by wind erosion and hydraulic erosion.Wind erosion accounts for the majority and hydraulic erosion accounts for a small part.The number of samples in areas with moderate wind erosion is the largest,and the degree of wind erosion is at a high level.The soil bulk density and soil water content are distributed in a strip in space.The soil bulk density is the maximum in the north of the study area and the minimum in the south of the study area.The soil water content in the south of the study area is the largest and the soil water content in the north of the study area is the smallest,showing a spatial transition trend,but the change trend is opposite ;The main biological indexes of desert grassland area show a transitional trend in space,which is distributed in strips.The biomass in the southeast is higher,the biomass in the northwest is smaller,and the biomass increases gradually from the northwest to the southeast.

Mots clés : Grassland degradation ;Spatial variation ;Soil quality ;Desert grassland ;Siziwang Banner ;

Présentation (CNKI)