我国半干旱荒漠草原典型植被群落对土壤入渗特性的影响

A process of infiltration from the soil surface to form soil water is known as soil infiltration;this is the only way for plants to absorb and use soil water.This process is closely related to nutrient migration,surface runoff,and soil erosion.In recent years,human disturbances such as global climate change and overgrazing have undermined the stability of grassland ecosystems.Large-scale grassland degradation,patch exposure,high degree of surface compaction,easy to form surface runoff,resulting in increased soil erosion process.In water-limited areas,rainfall infiltration is the main way to supplement the water required for plant growth.Water infiltration into soil is a key process to supplement soil moisture in root zone in arid and semi-arid areas.Previous studies mainly focused on the effects of soil properties and vegetation types on soil infiltration process.On this basis,this paper further explored the influence mechanism of soil properties,vegetation types and vegetation root characteristics on soil infiltration rate.Therefore,this paper takes six typical plant communities(Allium mongolicum community,Convolvulus ammannii community,Stipa grandis community,Leymus chinensis community,Koeleria macrantha community,Stipa breviflora community)in Xilamuren grassland as the research object.Six typical community types were selected by field quadrat survey and two-way indicator analysis.The parameters of vegetation roots were analyzed by root analysis system.The soil infiltration rate of 0-30 cm soil layer in six typical vegetation communities was determined by cutting ring method.The effect of typical plant communities on soil infiltration performance was quantified,the interaction between soil infiltration rate and soil characteristics and plant roots was revealed,and the main factors affecting soil infiltration performance in Xilamuren grassland were determined.The results indicated that the infiltration rate of the Koeleria macrantha community was highest at the soil depth of 0-5 cm,while that of the Convolvulus ammannii community was lowest,reaching 4.25 mm·min-1 and 0.53 mm·min-1,respectively.The soil infiltration rate of different plant communities gradually declined with the increment of soil depth.The strongest correlations were found between bulk density,total porosity,organic matter,root characteristics,and soil infiltration rate.The bulk density,initial water content,capillary porosity,and clay content were the primary influencing factors acting on soil infiltration in the region.Other factors indirectly impacted the infiltration rate by modifying bulk density,which was a crucial limiting factor determining the infiltration rate in the research region.The study's findings will give theoretical and practical assistance for the prevention and management of soil deterioration and grassland restoration in this area.