Spatial Heterogeneity of Soil Mineral Composition in Secondary Forest in Karst Cluster-peak-depression Region

This study was carried out to examine the spatial heterogeneity of soil minerals(SiO2、Fe2O3、CaO、MgO、Al2O3、MnO) in secondary forest in karst cluster-peak-depression region using methods of classical statistics and geostatistics.Eighty soil samples of 0cm-20 cm layer were taken on the 200 m × 40 m scale.The results showed that the differences of the six mineral compositions were large,and the contents of soil mineral compositions were in the order of SiO2 CaO Al2O3 MgO Fe2O3MnO,and the variance coefficients ranged from 37.8% to 54.6%.Gaussian model fitted best for MnO,and Spherical model fitted best for other mineral compositions.MgO had medium spatial autocorrelation,while the others were characterized by strong spatial autocorrelation.The Kriging contour map of CaO was similar with that of MgO.The Kriging contour maps of Fe2O3,Al2O3,and MnO were similar.Most of the high-value area of SiO2 appeared on upper slope and a small on the mid-low slope.The results indicated that topography,micro-physiognomy,precipitation,human disturbance,and especially vegetation were the most important factors affecting the spatial pattern of soil mineral composition.Increasing plant diversity and coverage would be of great importance for improvement of soil mineral composition,rational utilization,and ecological restoration and reconstruction.