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土壤水分是植被格局形成和演变的主要因素,土壤水分的空间异质性对于认识干旱区草原植物对环境的响应机制具有重要意义。应用地统计学方法,对祁连山北坡甘肃臭草(Melica przewalskyi)退化草地土壤表层含水量的变异性进行研究。结果表明,臭草型退化草地浅层(0～30 cm)土壤水分符合正态分布,土壤含水量沿垂直方向逐渐增大,介于9.56%～11.21%。各层土壤水分的变异系数分别为12.97%(0～10 cm)、8.8%(10～20 cm)和14.09%(20～30 cm),均属弱变异;0～30 cm土壤含水量具有高度的空间异质性,其中34.92%～42.71%的空间异质性是由空间自相关部分引起的,主要体现在16.87～69.14 m尺度上。在0～10 cm土层,引起土壤水分空间变异的主要因素是植被覆盖度的不同,而在10～30 cm土层,土壤水分空间变异性主要是根系分布的差异引起的。
Soil moisture is the main factor for the formation and evolution of vegetation patterns. Spatial heterogeneity of soil moisture is of great significance for understanding the response mechanism of grassland plants to the environment in arid areas. The geostatistics method was used to study the variability of surface water content of degraded grassland of Melica przewalskyi in the northern slope of Qilian Mountains. The results showed that the soil moisture in the shallow layer (0-30 cm) of the stink grassland degraded grassland was in normal distribution, and the soil water content increased gradually along the vertical direction, ranging from 9.56% to 11.21%. The coefficient of variation of soil moisture was 12.97% (0-10 cm), 8.8% (10-20 cm) and 14.09% (20-30 cm) in each layer, which were all weakly variable. Soil water content in 0-30 cm was highly Of the spatial heterogeneity, of which 34.92% ~ 42.71% spatial heterogeneity is caused by the spatial autocorrelation, mainly in the 16.87 ~ 69.14 m scale. In 0 ~ 10 cm soil layer, the main factor that caused the spatial variation of soil moisture was the difference of vegetation coverage. However, the spatial variability of soil moisture in 10 ~ 30 cm soil layer was mainly caused by the difference of root distribution.