Study On Soil And Water Conservation Benefits Of Camellia Forest In Quaternary Red Soil Texture

Camellia oleifera is a unique kind of woody oil tree, widely cultivated in the hilly area of Southern China.Quaternary red soil texture is widely developed in tropical and subtropical regions in the Southern China, Its’ spatial distribution is consistent with the distribution of the Red Soils. Because C.oleifera is fond of acidic soil,Red soil area is very suitable for planting in the southern, and also because of the support of national and local government, a large area of C.oleifera cultivation in the southern hilly area, what’s more, after the destruction of natural forest, original mountain transform to C.oleifera forest. It is undoubtedly harmful to the natural environment. Nowadays, The studies on water and soil conservation effectiveness of C.oleifera is rarely, and most researches focus on the study of C.oleifera forest-related growth characteristics and quality of forest soil fertility, more researches are focus on the causes of Quaternary red soil texture and soil physical & chemical properties, but the soil and water conservation benefits of C.oleifera who grow in the Quaternary red soil texture is very scarce. This study can provide the quantitative data of C.oleifera forest’s soil and water conservation features and benefitson Quaternary red soil texture. in order to providea theoretical reference of methods and approaches to further improve the C.oleifera forest ecosystem hydrological functions, restore and rehabilitate the degraded forest ecosystems.The C.oleifera forest in Quaternary red soil textured of Skyline Ridge Artificial in Changsha City as the research object, positioning observate canopy interception, throughfall,surface runoff, sediment losses and soil factors at different stand age (7-8 years-old C.oleifera forest and 4-5 years-old C.oleifera forest)of C.oleifera forest vegetation recovery mode in test area. We selected the abandoned land as contrastive plot to comparative analysis canopy interception, surface runoff characteristics, sediment loss and physical&chemical properties of soil in different age of C.oleifera forest vegetation recovery mode, to study different stand age of C.oleifera forest improved the soil physical & chemical properties.the interception of rainfall.the surface runoff and sediment losses.to be able to evaluate the soil and water conservation benefits of C.oleifera forest in Quaternary red soil texture.The main results are as follows:1.The C.oleifera forest can obviously improved soil physical properties of Quaternary red soils texture,and the soil quality after a long planting C. oleifera forest has continuously improved.2.The C.oleifera forest has a certain improvement in Quaternary red soils’pH value. During the growth of the C. oleifera forest, organic matter content and nitrogen content of each soil layer increased obviously with increasing stand age.3.Due to the growth needs of the C. oleifera forest, K, Available P, Ca, Mg, Cu, Fe, Zn, Mn content in soil had in varying degrees of change,Camellia Forest of nutrients in soil texture Quaternary red soil region has a certain improvement and enrichment. Also, because of the influence of environmental factors——warm and rainy, the leaching phenomenon is serious, the South Quaternary red soils texture area generally have insufficient phosphorus supply phenomenon.4.C. oleifera forest canopy interception of adsorption and plants absorption significant-ly reduced the heavy metal elements Cd content in soil which mainly recycle through rainfall. C.oleifera forest adsorbed parts of Pb in rainfall through the canopy, it shows that the higher canopy density value, the more the content of Pb adsorbed and thus the less Pb content in soil.5. The testing ground’s soil physical & chemical properties of the correlation analysis results showed that:between Total P content and Cd content, Ca content and Cu content, Cd content and Fe content were extremely significantly correlated. There were significantly correlations between Organic matter & total N, Ca, Pb content, total p & Fe content, Ca & Cd content, Cu& Pb content, Fe & Mn content, bulk density & total porosity were significantly correlated.6.Between the throughfall and rainfall outside the C.oleifera forest showed a significant positive correlation in different stand of ages and different canopy density, so between the throughfall rate and rainfall showed. But when rainfall increases to a certain degree,the throughfall rate was stable, no more increase. As rainwater increases, the amount of stemflow also increased. The amount of stemflow in 7～8 years-old C.oleifera forest is higher than 4-5 years-old C.oleifera forest on one single rainfall. This may be due to the short form of C.oleifera forest, branches many and scattered and main branch stout. Stem flow loss in the convergence process due to transpiration or the tree form7. With the increase of rainfall, the rejection rate of two stands age of C.oleifera forest both have suffered very significant downward trend, greater rainfall, the smaller the rejection rate. The rainfall interception effect of canopy was more significant especially with the increasing age of C.oleifera forest. Maybe this is due to the C.oleifera leaf area, the canopy density and canopy thickness.The high value can play better absorption and retention effect to rainfall,decrease the amount of throughfall and reduce the kinetic energy of raindrops fell on the ground. In a way of water conservation benefits, prevent soil erosion,7-8 years-old C.oleifera forest is better than 4-5 years-old C.oleifera forest.8. Rainfall is the key factors which affecting the amount of soil erosion.The more rainwater, the more amount of soil erosion, a positive correlation between the amount of rainwater and soil erosion. Different vegetation structure shows different size reaction of rainfall. Loss of soil in abandoned land increasing substantially with increasing surface runoff. The soil and water conservation effect of 7-8 years-old C.oleifera forest is the best.