The variation of soil water content and its driving factors in different melting periods in the Three River Headwaters Region: A implication for vegetation restoration

Abstract

The variation of soil water content (SWC) and its driving factors are usually vital in developing vegetation restoration and ecological protection in permafrost regions. Here, to understand how SWC varied with time and space in different soil layers and to propose strategies of vegetation restoration in the Three River Headwaters Region, we collected 955 soil samples at a regional scale during 2019 to 2021. The results indicated that SWC was higher in the southeast of the region, but lower in the northwest, and the distribution range of the high value area of SWC was the largest in August and the least in July. It showed a decreasing trend with the increase of soil depths, SWC in June was 17.19 %–26.13 %, in July was 18.30 %–22.15 %, in August was 19.74 %–30.47 %, and in September was 19.20 %–27.33 %, and the mean SWC of 0–80 cm was August > September > June > July. At the entire regional scale, soil bulk density exerted a first order control on the SWC variation. Moreover, slope gradient, normalized difference vegetation index, temperature, and altitude played important roles in affecting SWC in different melting periods. The results provided effective implications for proposing corresponding strategies of vegetation protection and restoration in different melting periods. Our results provided scientific support for water resources management, vegetation restoration, and ecological protection in this region.