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Ningxia University (2019)

Study on Plant-Hydrological Effects of Biological Soil Crusts


Titre : Study on Plant-Hydrological Effects of Biological Soil Crusts

Auteur : 杨东东;

Grade : Master’s Theses 2019

Université : Ningxia University

Résumé partiel
Biological soil crust plays an important and crucial role in the dynamics and distribution pattern of desert steppe vegetation.Clarifying the plant and hydrological effects dominated by biological soil crusts has extremely important theoretical and applied research value for understanding the stability mechanism of desertified grassland in desert steppe.Artemisia scoparia is a dominant species in the study area,and it is also a typical 1-year-old shallow root plant.It analyzes the dynamic changes of root growth and soil moisture under the cover of biological soil crust,which helps to clarify the study of Artemisia scoparia.The adaptive mechanism of dominant species in the area can also be used as an indicator plant to better understand the plant and hydrological effects of soil crusts in desert steppe.Based on this,we compared the soil hydrological and physical characteristics of the surface layer with or without crust,the growth dynamics and size of the roots of Artemisia scoparia,and the change of water source.The main findings and conclusions are as follows :(1)Effects of Biological Soil Crust on Hydrological and Physical Characteristics of Surface Soil:Compared with the non-crust covering,the moisture content of the crust layer in the surface soil with crust cover showed a diametrically opposite pattern in the dry season and the rainy season.The water holding effect was mainly in the small precipitation,and the summer evaporation was strong.Typically,the relative water holding effect of the crust that enters the rainy season is weakened or even lost.Due to the seasonal conversion of biological crust activity,surface soil bulk density,saturated water content and total porosity have changed to varying degrees on seasonal scales.Whether in the dry season or the rainy season,the presence of biological crust reduces the soil water infiltration performance,and the soil water infiltration rate in the rainy season is lower than that in the dry season with or without crust cover.(2)Effects of Biological Soil Crust on Morphology and Growth of Shallow Roots of Artemisia scoparia:The changes of the morphological indexes of the roots of the genus Artemisia argyi in the whole growing season with different skin layers were observed.It can be seen that the root weight of the roots of the genus Artemisia serrata in the fixed volume increased with the increase of drought degree in the dry season in May and June.The root length,surface area,volume,number of root tips and number of branches showed an increasing trend,and all indicators reached the maximum value of the whole growing season,entering the rainy season from the dry season(June)(July)The root morphological index values of Artemisia scoparia were sharply reduced.In July,August and September,only the root weight showed an increasing trend with the increase of the month

Mots clés : desert steppe; biological soil crusts; Artemisia scoparia; water source; root structure;

Présentation (CNKI)

Page publiée le 27 mai 2020