Soil,and Water Conservation And Nutrient Loss Control In A Reconstructed Tea Garden

The point source pollution is gradually being controlled,while,the problem of agricultural non-point source pollution is becoming more and more prominent.Tea,as one of the important economic forests in hilly areas of southern China,is also an important research object of soil and water loss and agricultural non-point source pollution.In Hengxi Reservoir Basin of Ningbo City,Zhejiang Province,during the research period of National Key Research and Development Project,a large number of tea plantations were rebuilt and partly reclaimed due to property rights changes.Therefore,as a part of the project,the law of soil and water loss and nutrient loss in reconstructed tea garden was explored,and the experimental study on prevention and control of soil and water loss and non-point source pollution in reconstructed tea garden was carried out.According to the requirements of the project,the technical integration of soil and water and nutrient loss prevention and control was taken as the main content,and the optimized fertilization technology,vetiver planting technology and film mulching technology with the function of water conservation and grass pressing were combined to carry out the research on soil and water loss and nutrient loss reduction in tea garden.In order to study the reconstructed tea garden in one year,two years and three years,18 PVC enclosed plots of 40 square meters were established,and experiments on optimized fertilization treatment,soil and water loss interception treatment and soil film mulching treatment were set up.Based on the analysis of the experiment results,the main conclusions are as follows:(1)In the early stage of reconstruction of tea garden,soil and water and nutrient loss were great,but it tended to be stable quickly.The amount of soil erosion was 128.0 kg/ha in the one-year reconstructed tea garden,while the amount of erosion sediment was not monitored in the two-year and three-year reconstructed tea garden.Therefore,under the condition of optimized fertilization,the risk of non-point source pollution in the reconstruction of tea garden can be greatly reduced as long as the protective measures are taken in the early stage of tea garden reconstruction.(2)The experiment of fertilization treatment showed that the runoff loss of nitrate nitrogen and total phosphorus under conventional fertilization was significantly higher than that of control treatment and site-specific nutrient fertilization and slow-release fertilizer replacement treatment.The latter could reduce the runoff loss of total nitrogen,nitrate nitrogen and total phosphorus by 7.7%,22.7%and 58.1%,respectively,and significantly slow down the non-point source pollution of tea plantation.(3)The vetiver experiment showed that proper intercropping of vetiver grass could play a role in the fifth month after planting in reconstructed tea garden.In the first year of planting vetiver grass,the loss of runoff,sediment,nitrogen and phosphorus in the whole year could be reduced by 23.7%,94.3%,17.4%and 66.2%,respectively.(4)The film mulching can play a good role in inhibiting the growth of the weeds and reducing the drought disaster of soil moisture in reconstructed(newly built)tea garden,but the experiments showed that the mulching could increase the loss of runoff,nitrogen and phosphorus by 6.8%,10.1%and 36.8%,respectively.(5)There was a significant correlation between rainfall intensity and rainfall and runoff nitrogen loss in tea garden,which was the main driving force of soil and water loss and non-point source pollution in tea garden.The functional relationship between soil and water loss and nitrogen and phosphorus loss in tea garden was established,and the key role of reducing runoff and sediment loss in tea garden in controlling nitrogen and phosphorus loss was further analyzed.