景观复杂地区土壤有机质变异的多尺度特征——以河南省登封市土壤为例

为研究景观复杂地区土壤有机质变异的尺度特征,以河南省登封市为研究区,探讨了该市土壤有机质在不同尺度、不同景观类型区的变异特征。结果表明:(1)2 km采样间距的大尺度土壤有机质平均含量和变异系数分别为20 g kg-1和44.8%;200、300、300和500 m间距的小尺度4个景观类型区:紫色土区、中山石英砂岩区、山前洪积扇区和低山丘陵洪积物母质区,有机质平均值和变异系数分别为15.72、15.53、26.00、18.98 g kg-1和29.9%、26.21%、16.04%、35.41%。(2)不同尺度、不同景观类型区土壤有机质的半方差函数,在块金值、基台值和变程等参数上有较大差异。(3)大尺度土壤有机质与高程因子、坡向因子呈极显著和显著相关性,与坡度相关性不明显;除了低山丘陵洪积物母质区与高程因子极显著相关外,小尺度土壤有机质在紫色土区、中山石英砂岩区和山前洪积扇区均和高程、坡度、坡向无显著相关性。

Scale Characteristics of Spatial Variability of Soil Organic Matter in Complex Landscape Region——A Case from Dengfeng City of Henan Province

Taking Dengfeng County as the study area,variation characteristics of the content of topsoil organic matter(SOM) was investigated for a better understanding of scale effect involved in spatial variability of soil attributes in a complex landscape.It was found that the mean SOM content and the variation coefficient in the whole study area were 20 g kg-1 and 44.8% respectively,when soil sampled under the 2×2 km grid control.In the landscape type of landscapes located in the study area,namely Purple Soil Zone,Quartz Sandstone Zone,Proluvial Fan and Diluvium Zone.Topsoil was sampled at smaller pace and under 200×200 m,300×300 m,300×300 m and 500×500 m grid control respectively,the predicted values of the SOM contents were 15.72 g kg-1,15.53 g kg-1,26.00 g kg-1,18.98 g kg-1,with the corresponding variation coefficients 29.9%,26.21%,16.04%,35.41%.The significant differences were found in semivariance amongst different landscapes and sampling densities.And,at the study area scale,extremely significant and significant correlation between SOM and terrain factors elevation and aspect was demonstrated,while the significant correlation between SOM and slope failed to be found.At the landscape scales,there was no significant correlation between SOM and terrain factors,except for the extremely significant correlation between SOM and elevation in the Diluvium Zone in Low Mountain or Hill of the study area.