Spatial Heterogeneity of Topsoil Moisture and Litter Lay in Natural Populus davidiana-Betula platyphylla Secondary Forests
Litter layer was an active layer of humidity control in forest ecosystem,it was important to hydrologic cycle of forest ecosystems.In the study,semivariance analysis of geostatistics was employed to quantify the spatial heterogeneity of topsoil moisture and litter layers of different degree of decomposition in natural Populus davidiana-Betula platyphylla secondary forests.The results showed that,the semivariograms of topsoil moisture,undecomposed,intermediate decomposed and decomposed litter layers were best described by exponential model,their structure ratio were 88.3 %,66.6%,89.2% and 57.79%.Undecomposed and decomposed litter layers had moderate spatial autocorrelation,while topsoil moisture and intermediate decomposed litter layer had strong spatial autocorrelation.Analyzing of fractal dimension of the 4 measured variables revealed that,spatial distribution pattern of topsoil moisture content and depth of litter layers had no remarkably anisotropic.From fractal dimension values,topsoil moisture was 1.981;intermediate decomposed litter layer had the highest value,which was 1.967.It was clearly apart from the other two litter lays.Fractal dimension of undecomposed and decomposed litter layers was 1.925 and 1.928.For spatial distribution pattern,intermediate decomposed layer was obviously fragmentized distributed,there were no remarkable differences in east-west and south-north directions.Topsoil moisture,undecomposed and decomposed litter layers had continuous spatial distribution.From different direction of distribution patterns,there were remarkable differences in east-west direction,while not obvious in north-south direction.
国家科技期刊平台
NSTL
万方数据
维普
