Biological soil crusts (BSCs) have important ecological functions, including wind and sand fixation, promotion of nutrient cycling, and enhancement of desert surface soil stability in drylands. The relationship of biocrusts to the physical structure and function of desert soils and binding sand quantity (BSQ) is not clear, which is not conducive to a comprehensive understanding of the ecological functions of BSCs. This study aimed to investigate the characteristics of the physical properties of BSCs on soil stability and the response characteristics to drought and to analyze the interrelationships between physical properties and the response characteristics to drought by investigating and determining the surface roughness, thickness, compressive strength, shear strength, and BSQ in different types of BSCs. The physical properties (thickness, roughness, compressive strength, shear strength) and BSQ increased significantly with the development of BSCs. The cover could significantly affect the thickness, roughness, compressive strength, shear strength and BSQ. The BSQ and compressive strength show an increasing trend with increasing thickness and roughness. The physical properties, physical multifunctionality (P-SMF), and BSQ of biocrusts showed different trends with increasing aridity. The results of structural equation modeling also found that the P-SMF and BSQ of biocrust had different response characteristics under different aridity levels. The development of biological crust is a fundamental factor affecting stability, and aridity is an important driver for altering the soil stability of biocrusts. This study contributes to a comprehensive understanding of the structure and function of biocrusts from multiple perspectives, especially the understanding of biocrusts for wind prevention and sand fixation, as well as surface stability. This study provides a new methodology and new ideas for the distribution and surface stability of biocrusts and is of great significance for land management and conservation in drylands.
 

Biological soil crust,dryland,multifunctional,physical,roughness