Study on Spatial-Temporal Changes on Undergrowth the Plantation Soil Bulk Density and Soil Porosity of Quanshan Nature Reserve in Xuzhou

The soil bulk density in four sampling areas in Platycladus orientalis plantation forests and Robinia pseudoacacia forest of Quanshan Nature Reserve in Xuzhou are determined and compared with that in bare area.The results show that there’s no rule of the variation between undergrowth soil bulk density and soil porosity and the depth;while the rule of the variation of undergrowth soil spatial structure is clear.Regardless at what time the soil bulk density gets larger with the soil gets deeper while the soil porosity gets smaller with the soil gets deeper,besides,the effects of Platycladus orientalis plantation forests is larger than that of Robinia pseudoacacia forest.Besides,the soil bulk density of park greenery plot soil is larger than that of bare area and the soil bulk density gets smaller by the humus of plantation,which makes the penetration and retentivity fertilizer get better.