长白山阔叶红松林表层土壤水分空间异质性的地统计学分析

Spatial heterogeneity of surface soil moisture in a broad-leaved Korean pine forest in Changbai Mountains based on geostatistic analysis

采用时域反射仪对长白山原始阔叶红松林3块50m×50m样地表层土壤(0～7.5cm)水分进行测定,应用地统计学的理论与方法对表层土壤水分的空间异质性进行分析.结果表明:研究区3块样地表层土壤水分变异系数分别为24.32%(样地1)、24.11%(样地2)和23.60%(样地3),均属于中等变异性;该区表层土壤水分的理论变异模型为球状模型,具有高度的空间异质性,其空间异质性以空间自相关部分为主;表层土壤水分的结构比分别为57.9%(样地1,属中等相关性)、83.3%和90.0%(样地2和3,属强烈的空间相关性);研究区表层土壤水分的变程在5.5～13.1m,与贝叶斯方法估计的变程相差不大;通过克立格插值估计,研究区表层土壤水分含量的平均值分别为49.3%(样地1)、52.8%(样地2)和42.6%(样地3).

By the methods of geostatistics,this paper studied the spatial heterogeneity of surface soil moisture in a broad-leaved Korean pine forest in Changbai Mountains.Three sampling plots sized 50 m × 50 m were installed,and the moisture content in 0 -7.5 cm soil layer was measured with a time domain reflectometry.The coefficient of variation of the surface soil moisture was 24.32% in plot 1,24.11% in plot 2,and 23.60% in plot 3,suggesting a moderate variability.The variogram of the surface soil moisture could be well fitted by spherical model,and had a higher spatial heterogeneity,which mainly came from spatial autocorrelation.The structural ratio of surface soil moisture was 57.9% in plot 1,83.3% in plot 2,and 90% in plot 3,and the regressed range（distance beyond which samples were spatial independent,an indicator of patch size） was 5.5-13.1 m,being consistent with the results from Bayesian method.Through Kriging interpolation,the surface soil moisture content was 49.3% in plot 1,52.8% in plot 2,and 42.6% in plot 3.