中文摘要：

为揭示小区尺度乃至微尺度土壤含水率的空间变异性,在杨凌地区猕猴桃果园选取40 m×40 m区域,并在此基础上再以8、2 m为间距进行网格划分,基于经典统计学和地统计学理论,对不同采样密度条件下0-60 cm土层土壤含水率的空间分布特征及其空间变异性进行了研究。结果表明,对于40 m×40 m（L）、8 m×8 m（M）和2 m×2 m（S）3种尺度,0-60 cm深度各土层土壤含水率在水平方向上的变异强度表现为弱变异至中等（偏弱）变异,且随尺度减小和土层深度增加而减小,且所有取样点处0~60 cm深度内土壤含水率在垂直方向上的变异强度表现为弱变异至中等（偏弱）变异。在3种尺度中,土壤含水率存在强烈的空间相关性,表征土壤含水率空间分布形态的半方差函数因尺度不同存在较大差异,L尺度可采用球状和指数模型,M尺度可采用线性模型,S尺度可采用高斯、指数、线性模型。L尺度合理取样数较实际少,而M和S尺度合理取样数较实际多,对于3种尺度,基本表现出0-30 cm土层合理取样数较实际多、30~60 cm土层合理取样数较实际少,表明取样点的合理性分布有待进一步优化。由于地形原因导致当地果园内南北侧土壤含水率空间分布存在较大差异。

英文摘要：

A study on spatial variability of soil moisture for micro-scales was conducted in a kiwi field in Yangling region. The mesh generation was formed based on the separation distance of 8 m, 2 m and 0. 5 m in the 40 m × 40 m field. The spatial distribution and variation of soil moisture in 0 - 60 cm soil layers under different sampling densities were analyzed based on classical statistics and geo-statistics theories. Results showed that as for three micro-scales of 40 m x40 m （L）, 8 m ×8 m （M） and 2 m × 2 m （S）, the variability of soil moisture in 0 ~ 60 cm soil layers was weak and moderate in horizontal direction, and it decreased with the decrease of scale and the increase of depth. Meanwhile, the variability of soil moisture in 0 - 60 cm soil layers was also weak and moderate in vertical direction. A strong and significant spatial correlation was found in soil moisture in these three scales, and the semi- variance models for soil moisture varied with scales. This meant that semi-variance models for soil moisture in L scale could be simulated by spherical and exponential models; semi-variance models for soil moisture in M scale could be simulated by linear model; and semi-variance models for soil moisture in S scale could be simulated by Gaussian, exponential and linear models. Besides, the reasonable sampling amount in L scale was less than actual amount, but the reasonable sampling amounts in both M and S scales were more than actual amount. And as for L, M and S scales, the reasonable sampling amount in 0 -30 cm layer was more than actual amount, but the reasonable sampling amount in 30 -60 cm layer was less than actual amount. These results indicated that a reasonable layout of sampling point needs to be further optimized. In Yangling region, a significant difference of the spatial distribution of soil moisture could be found in the north and south of local kiwi field due to topography. These results could provide some guidance for irrigation and water control in precision agriculture.