Abstract:  Using the soil temperature data measured in 5 soil layers from 0 to 20 cm underground at weather station in Lishui from 1980 to 2010, the variation trend, abrupt changes of soil temperature and its response to climatic change in Lishui were analyzed in terms of methods of a linear trend analysis, a Mann-Kendall test and a correlation analysis. The results indicate that the annual mean soil temperature is in a significantly increasing trend with the ratio of 0.18 ℃/10 a, especially in winter. There is a peak value for the mean monthly soil temperature in Lishui. The amplitude of soil temperature variation decreases with the increase of the soil depth, and there exists a certain time lag. According to the Mann-Kendall test, the soil temperature is in a stable increasing trend in Lishui, especially from 2004 to 2009 in five soil layers, and it passes the test of 0.01 confidence level. The abrupt change of soil temperature in five soil layers lags with the increase of soil depth. The abrupt change of mean annual soil temperature occurs during 1994-1996. Soil temperature is in a significant positive correlation with air temperature, while it is in a significant negative correlation with spring and summer precipitation in Lishui, which is the response of soil temperature to climate change.

Key words: Soil temperature, Climate trend, Mann-Kendall abrupt change test