Abstract. In this research, the variations and spatial distribution of soil heat capacity in soybean field and sugarcane field under drought, moderate and humid soil moisture conditions were studied. The soil heat capacity in order to analyze spatial distribution by geostatistical analyst in each plot covered was calculated by the measured soil moisture content, furthermore, the states of dry, moderate and wet soil moisture conditions were determined. The result showed the soil heat capacity was greatest in sugarcane plot but lowest in soybean plot, which was similar to the change of soil moisture content under three soil moisture conditions. It suggested that the soil water content was a primary factor resulting in the change of the soil heat capacity. According to the results of geostatistical analysis of soil heat capacity, the spatial structure ratio of soil heat capacity is 57% -93% under three soil moisture conditions, which belongs to strong moderate spatial relativity. The high threshold spatial distribution of soil heat capacity in soybean and sugarcane fields is stable under drought and humid conditions, which indicates that the soil itself has the ability to restore the stability of its spatial distribution.

Abstract. This paper taking sugar cane, pear tree and soybean plots as an example, using software SSS to fit soil shrinkage curve, studies the effect of moisture content in the field on soil shrinkage. The results show that the model parameters of SSS software could fit the measured data well(r>0.95) with relatively small error; the differences of soil shrinkage between three upland crops successfully verify that the capacity of soil shrinkage directly proportional to moisture content, particularly to initial moisture content.

Measuring soil water content, soil water repellency and analysis spatial variation of the sugarcane land by combining classical statistics and geo-statistics, in this article. The results showed that: the means of soil moisture content and soil water repellency were smaller, in the case of long time without rainfall and these two soil properties were positively correlated. The distribution of soil moisture content and soil water repellency in the spatial distribution was similar, as well as the high threshold values were distributed in the northeast corner. The analysis results of the spatial variability degree for soil water content and soil water repellency were the same, meanwhile, variable coefficient and spatial correlation of soil moisture content were shown as medium, but soil water repellency shown as less relevant, under variable coefficient and geo-statistical spatial structure analysis.