Statistical characteristics of soil water content at farmland of the Horqin Sand Land

摘要

Based on the observed data of soil water content (SWC) at farmland from May to September in 2009～2012, the statistical characteristics of SWC in farmland at different soil depths (from 0 to 150 cm) and different months in the growing season (from May to September) in Korqin Sand Land were analyzed. In addition, by Skewness, Kurtosis test method, the normality of SWC of farmland in different soil layers and different months were tested. And then, we obtained the estimates and the confidence interval of the mean and variance for the normal distribution of SWC. The results indicated that: (1) The SWC of farmland at the same month and same soil depth passed the hypothesis testing of normal distribution at the significance level of α = 0.1; (2) SWC of farmland changed from 12% to 28% in 2009～2012; The standard deviation of SWC at farmland was 2～6; and the variation coefficients between 0～1, that was, belonged to the medium variation; (3) SWC at farmland was highest in July, and significant difference with other month in the growing season; And hence, the estimates and confidence interval for the mean and variance of SWC in July were significantly different from other month of the growing season; (4) SWC of farmland was lowest at 0～10 cm and differently from other soil layer, and it was highest at 120～150 cm; the change characteristics of the average value of SWC at farmland with soil depth was firstly increased, and then decreased, and finally increased.