Research On The Spatial Pattern Of Quercus Glauca Stone Forest Soil Carbon Storage And Potassium Content

Forest soil plays an important role in ecosystem due to its ability to maintain the sustainability of forests, soil is affected by many factors, such as parent material, landform, climate or man-made factors. Therefore, soil has a high degree of spatial heterogeneity. Finding out the relationship between the spatial heterogeneity and those influence factors are helpful for further study. Based on geostatistics theory, spatial heterogeneity of forest soil C and total potassium concentration in Lithocarpus glaber-Cyclobalanopsis glauca evergreen broad leaved forests was investigated by using semi-variogram of geostatistics and GS+ version 9 software. We collected 300 soil samples from 100 10 m 10 m quadrats at 0-10 cm,10-20 cm and 20-30 cm depth, The results showed that:The average C concentration of soils at 0-30 cm depth was 21.21 t · hm-2, and coefficient variability was at the intermediate range with an obviously spatial heterogeneity. Exponential model was best fitted to soil C concentration at each layer, At the 10-20 cm depth, C/(Co+C)>0.7, indicating a intermediate spatial autocorrelation. At the 0-10 cm,20-30 cm and 0-30 cm C/(Co+C)>0.9, indicating a low spatial autocorrelation between the C concentration of surface layer and deep layer soil. Soil C concentration in all layer was correlated with altitude, gradient and convex-concave, but the correlation was non-significant, these results showed that terrain factors had little influence on the C concentration of soil.The average K concentration of soils at 0-30 cm depth was 28.04 g · kg-1 and coefficient variability was at the intermediate range with an obviously spatial heterogeneity. While linear variogram function was best fitted to soil K concentration at 20-30 cm depth, spherical variogram model was best fitted to soil K concentration at 0-10 cm,10-20 cm, and 0-30 cm depths, indicating a strong spatial dependency. The spatial correlation distances (range) of K concentrations were 37.51 m for soil of 0-10 depth,25.38m for soil of 10-20cm depth,39.78m for soil of 20-30 cm depth, and for soil of 0-30 cm depth. Soil K concentrations across all layer exhibited a clear patch distribution pattern, with the lowest values at the middle and lower ridge, and the highest values at upper and southwestern corner. Soil K concentration was significantly correlated with altitude and soil clay content, implying that soil spatial heterogeneity could be attributed to pattern material and topographical factors.