The Upper Broadleaf And Lower Bamboo Mixed Business Model Effect On Soil Physical Properties And Soil Organic Carbon

This paper research the upper broadleaf and lower moso bamboo mixed forest existingbroadleaf forsst on that the mountaintop.We analysised the effects of mountaintop broadleafforest on the soil physical property, soil mechanical composition, soil aggregates structure andsoil organic carbon of bamboo forest.This paper totally researchedⅠ,Ⅱ,Ⅲ,Ⅳ four types. Theproportion of broadleaf forest on the mountaintop in total slope projection area respectively is27.5%,25%,18.6%,0%. Type Ⅳ is moso bamboo pure forest. The main conclusions are asfollows:1. Hydrology-physical indicators is soil bulk density, capillary porosity, non-capillary andthe storage capacity of soil. the method of topsis comprehensively assesses the soil physicalstructure in different types of moso bamboo forest. The merit of the order is Ⅰ>Ⅳ>Ⅱ>Ⅲ, typeⅠis the best.2. The study of soil mechanical composition in different types of moso bamboo forest showthat soil texture is as follows: typeⅠ,Ⅱand Ⅲ are loam, type Ⅳ is clay loam. The coefficientof variation of sand, silt and clay content show that typeⅠ,typeⅡand type Ⅲ are smaller thantype Ⅳ. Moreover, the content of sand and clay is significant with branch height, altitude, soilbulk density and total porosity of soil.3. Study on soil aggregates in different types of moso bamboo forest, mean weight diameteris Ⅳ<Ⅲ<Ⅱ<Ⅰ, and fractal dimension change with slope position is as follow: type Ⅰ and Ⅱare opening downward parabolic curve. the upper broad-leaved forest soil aggregates is low, andthen slowly increase in the upper slope, and then begin to decline in middle solpe. Type Ⅲ isopening uperward parabolic curve, the fractal dimension is broad-leaved forest> upper slope>lower slope> middle slope, fractal dimension of Type Ⅳ is the uphill slope> downhill, which isstraight-line trend.Relationship among of mean weight diameter, fractal dimension and each particle size classof soil water stability of aggregates are significantly correlated. Using stepwise regressionanalysis obtained that the main factors of the fractal dimension is <0.25mm water stableaggregates and mean weight diameter, the regression equation Y=2.282+0.22X7+0.051X8. X7is<0.25mm water stable aggregates, X8is mean weight diameter.4. In the slope position, the soil aggregates of organic carbon of type Ⅰ is middle slope<lower slope <upper forest <broad-leaved forest, type Ⅱ is middle slope <upper forest <lower slope <broad-leaved forest, type Ⅲ is broad-leaved forest <upper slope <middle slope <lower slope, type Ⅳ is upper slope <middle slope <lower slope. The upper slope soilaggregates of organic carbon in typeⅠandⅡare increased. Each particle size class of soil organiccarbon and total soil soil organic carbon achieve significant level, using partial correlation analysis the main factor affecting soil organic carbon is2~3mm soil aggregates.5. In the soil profile, various indicators in different types of moso bamboo forest show0~20cm is better than20~40cm and40~60cm.The management of pure moso forest does notchange the distribution characteristics of the soil profile.Combination of the above conclusions, the study of The upper broadleaf and lowerbamboo mixed business model on soil physical properties and soil organic carbon is significant.Therefore, the upper broadleaf and lower bamboo mixed forest (usually above30%) is well inforest sustainability management.