Prevention Of Non-Point Source Pollution From Deciduous Forest(Chestnut Tree)

As one of the important economic crops in Zhejiang province,Chinese chestnut is widely planted on hills and slopes.Under the influence of rainfall,the forest slope of Chinese chestnut is easy to form surface runoff.A large amount of soil and nutrients enter the nearby water along with the surface runoff,causing serious Non-point Source Pollution and affecting the water quality.There have been researches on soil and water loss and environmental pollution in chestnut forest,but most of them focus on soil and water loss,and few on nitrogen and phosphorus loss.The Non-point Source Pollution control mode should be a comprehensive project of soil and water loss and nitrogen and phosphorus loss control.Therefore,it is of great significance to study the present situation of Non-point Source Pollution of chestnut forest and the comprehensive treatment model for the water environment security of Zhejiang province.In this study,the banli forest in hanggaizhen town,anji county was taken as the research object,and the Non-point source pollution status of the banli forest in zhejiang province was understood by combining investigation and experiment,and the treatment measures were put forward.On this basis,the comprehensive treatment model was put forward.The main findings are as follows: 1、Chinese chestnut is a deciduous cash crop,mostly planted on hills and slopes.In Chinese chestnut cultivation,Chinese farmers use glyphosate to clear the surface vegetation for years,resulting in land exposure,soil structure destruction,loss of soil and water,nitrogen and phosphorus,and Non-point source pollution.The research shows that rainfall and surface vegetation destruction are the main causes of soil and water loss,while the decrease of canopy density after deciduous leaves is not the main factor of soil and water loss,and the prevention and control period of Non-point source pollution should be from April to September when rainfall is relatively high.2、Different methods of surface vegetation clearance have a great impact on local vegetation.Compared with artificial removal or prohibition of herbicides,the surface biomass,soil moisture content,available nutrients and enzyme activity of herbicides used in successive years are greatly different.Herbicide control significantly increased the biomass of surface vegetation,which effectively curbed the loss of soil,water and nitrogen and phosphorus.Therefore,it is an effective method to prevent and control the Non-point source pollution of Chinese chestnut forest to adopt the measures of mountain closure and forest cultivation where conditions permit.3、The use of chemical fertilizer provides the nutrient source for the Non-point source pollution of chestnut forest.The change of fertilization method is conducive to the control of Non-point source pollution of economic forests in sloping land.The "Bamboo Tube Fertilization" invented by our research group can significantly reduce the concentration and loss of ammonia nitrogen,total nitrogen and total phosphorus in runoff,which has a good effect of emission reduction.4、Engineering technology is an important measure to reduce pollution from non-point sources.Covering,intercepting ditches,sand barriers and constructed wetlands can significantly reduce the content of mud and sand,total nitrogen,ammonia nitrogen and total phosphorus in runoff.5、Based on the experimental results,this study proposed a comprehensive control model of "controlling source greening,energy dissipation and interception,wetland absorption" based on the farming characteristics and farmers’ acceptability of chestnut forest slope,so as to provide technical support for further controlling non-point source pollution of chestnut forest land.