Soil temperature and moisture stratification characteristics in the marginal desert grassland of the Dzungaria basin

The wide distribution of arid and semi-arid desert grasslands, low soil temperature, and low soil moisture greatly affect the growth of desert vegetation and regional climate environment. The automatic observation data of soil temperature and humidity probes were obtained at a desert grassland site on the southern edge of the Gurbantonggute desert, Dzungaria basin, Xinjiang, from May 2017 to April 2019. The variation in the soil temperature and humidity at different depths and their correlation with meteorological data were analyzed. The results showed that: 1) The soil temperature and humidity of each layer had obvious periodic change characteristics with the seasonal change. The vertical gradients of soil temperature and humidity at different depths were obvious, and the surface layer had the biggest fluctuation. The shallow soil temperature obviously fluctuated with the seasons and reached a maximum value at 18:00. The trend in the soil moisture at 5 cm was spring > summer > autumn > winter, and soil moisture increased with the increase in depth. 2) The correlation between the soil temperature and meteorological factors was stronger than that with the soil moisture. The soil temperature was positively correlated with the ground temperature, air temperature, and evaporation, for which the correlation coefficients were 0.955, 0.942, and 0.823, respectively (P < 0.01). This paper presents the changes to the soil temperature and humidity in a desert-oasis zone, to provide a basis for the model simulation of land surface processes using initialization data.