Abstract: Based on observed data of soil moisture content (SW) at fixed sand dune (FD) in 0-150 cm and precipitation of May to September from 2006 to 2009, the normality of SW at FD in different month and different soil layer were tested by the skewness, kurtosis test method, and obtained the estimates of the relevant parameters and its confidence interval obeying normal distribution for SW; Moreover, we analyzed the change and difference of SW with different soil layer, different month and year. The results showed that: (1) SW of FD at the same month passed the hypothesis testing of normal distribution at the significance level of α=0.1; The averaged value of SW at FD ranged from 1.82% to 4.95%, and most concentrated in 2%-4%; (2) Influenced by precipitation, SW of FD was higher in July, and significant difference with other month; The estimates and confidence interval with confidence level of 0.95 for the mean and variance of SW at FD in July are quite different from other month; (3) SW of FD was lower at 0-10 cm and significant different from other soil layer; and SW was higher at 10-30 cm; (4). SW was lower in 2008, and higher in 2009; There was no significant difference for SW between 2007 and 2008, in addition to this, SW had significant difference in the other years.

Key words: soil moisture, skewness, kurtosis test, normal distribution, variance analysis