基于地统计学的甘肃臭草群落土壤水分空间异质性

Spatial Variability of Soil Mositure of Melica przewalskyi Community Based on Geostatistics

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 factors of vegetation pattern formation and development. The spatial heterogeneity of soil moisture have important meaning of understanding the response mechanism of plant environment In arid and semi-arid regions. In this paper, the spatial variability of soil moisture on the north slope of Qilian mountain was investigated based on geostatistical theory and methods. The research was carried out in an degraded grassland of Melica przewalskyi community. The results indicated that the distribution of surface soil moisture was normal distri- bution. The soil moisture at the 0 - 30 cm soil layer increased with the increase of depth was, on average, 9. 56% 11.21. The coefficient of variation of the surface soil mositure was 12. 97% （0 - 10 cm）, 8.8% （ 10 - 20 cm） andl4. 09% （20 - 30 cm）, all belong to a weak variation. There was high degree of spatial heterogeneity of sur- face soil moisture. Among them 34. 92% - 42. 71% spatial heterogeneity is caused by the spatial autocorrelation part, and the distance of spatial autocorrelation in vegetation coverage was found within distance from 16. 87 - 69. 14 m. Soil mositure content of the layer 0 - 10 cm is affected by coverage. In the 10 - 30 cm, soil mositure con- tent is affected by root.