Abstract: According to monitoring data of Inner Mongolia Dengkou Desert Ecosystem National Observation Research Station, the different depth soil temperature data and meteorological data in 2014 are analyzed to clarify the characteristics of soil temperature variation at northeast edge of Ulan Buh Desert. The results shows as follows:(1) The variation characteristics of soil temperature is consistent with air temperature at northeast edge of Ulan Buh Desert, while the appear time of highest and lowest air temperature is about 2 hours in advance comparing with the Badain Jaran Dessert and about 1 hour later comparing with eastern China. The change of soil temperature are identical to air temperature, and the soil temperature is about 1 hour later comparing with air temperature in each reason. (2) The change rate of soil temperature decreases with the increase of soil depth, and soil temperature keeps 0℃ when soil depth is below 70 cm in the whole year, and the duration time of 0℃ is about 4 months. (3) The variation tendency of soil temperature is consistent with air temperature and solar radiation, while the soil temperature lags obviously behind air temperature and effective solar radiation. The correlation analysis results revealed that the environmental factors affecting the variation of soil temperature are air temperature, evaporation, effective solar radiation, wind speed, air relative humidity and rainfall.

Key words: Ulan Buh Desert, soil temperature, soil depth, meteorological factors