| With continued growth of population,increasing demand for food and gradually increasing intensity of resource,which leads to agricultural non-point source pollution increasing year by year. Currently,agricultural nonpoint source pollution has caused soil and water pollution on a global scale. The situation of agricultural nonpoint source pollution n China is extremely serious.There are three main sources,namely,fertilizer,livestock manure and pesticides. In addition,the amount of production and application of pesticides in the world are the largest,and existing irrational,excessive usage of them among this phenomenon,not the effective use of pesticides in soil,water and long-term accumulation. Pesticides which are not effective utilized in soil accumulate long-term in water,increasing soil environment and water quality deterioration in rivers and lakes. Agricultural nonpoint source pollution has its unique characteristics,so it becomes one of the world’s toughest environmental pollution problems. Therefore,to explore effective prevention and control measures to curb agricultural nonpoint source pollution,soil fertility,soil and water conservation,reduce environmental pollution and ecological destruction have important theoretical and practical significance. Slope-mulberry system as a kind of hedgerow can mechanical fence block, absorb and reduce soil erosion in the system to improve the environment (improve soil erosion resistance,cover,reduce the slope,etc.). It can not only be well maintained water and soil in slope,but also significantly reduce the agricultural non-point source pollutants on soil and water hazards.In this study,taking slope purple soil in hilly area of Three Gorges reservoir area and upstream as an example,taking slope-Mulberry system as a kind of agricultural nonpoint source pollution control slope complex ecological agricultural techniques from the perspective of the basin. The experiment consisted of five treatments, which were CT treatment (crops were planted along transverse slopes), T1treatment (crops were planted along transverse slopes with mulberry trees on upper-slope and lower-slopes), T2treatment (crops were planted along transverse slope with mulberry trees on upper-slope, middle-slope and lower-slope); T3treatment (crops was planted along transverse slope with mulberry trees on middle-slope and the four sides of the slope); T4treatment (crops was planted along transverse slope with mulberry trees on four sides of the slope). This paper system,quantitative study in controlling N,P effect of agricultural nonpoint source pollution,the number of microbial biomass and activity,and complex evaluate the effects of Mulberry-economic slope systems-soil quality,provide a scientific basis for the promotion of pollution optimization technology on controlling regional agricultural nonpoint source,and provide important theoretical and practical significance in watershed protection of the water environment security,promote economic region-environmental development. Study achieved the following results:1In the season of mustard,intermittent,cora,as temperature,humidity,mulberry with growing,crop type and other factors,soil nitrogen content and the season was significantly positively related,and soil total potassium content and the season was significantly negative related. In the treatment of T1,T2,T3,T4,soil phosphorus,potassium content and the treatment was a significant positive correlation; nitrogen content and the treatment was a significant positive correlation. In addition,the correlation analyses were done between all the nutrients,nitrogen and potassium was a significant positive correlation,the total nitrogen content in soil,soil total phosphorus and available phosphorus content was significantly positive correlation,nitrogen content in soil and soil total K content was significantly negatively correlated,soil pH and soil available phosphorus was a significant negative correlation. Comprehensive obtained in four different treatments,there were a great influence on soil nitrogen content,appeared significant correlation; secondly,the impact on soil available phosphorus and potassium content was great,there were significantly correlated. Besides,other soil nutrients of each slope-Mulberry systems treatment were not very different,and there were not significant relationships.2Among all the treatments,the most obvious effect of run-off were T3and T4. T1and T2treatments’intercepted effects were not obvious because of issues such as mulberry growing. Each treatment has great impact on the nutrients of run-off,especially nitrogen content of run-off,which showed a significant negative correlation means that each process has effectively blocked the flow of water carried soil nutrients,and protect soil nutrient accumulation. However,each treatment has little effect on the number of microbial biomass,moreover,the bacteria and treatment showed a significant negative correlation,which makes the test designed inconsistent with the experimental results obtained. This result is an objective test or testing process was an accidental phenomenon,which worth further study to be demonstrated. In addition,crop nutrient absorption of each treatment was not very different,and treatments did not show correlation.3After the evaluation of economic output and soil quality,we can conclude that T3treatment,from the economic point of view,reached the highest value per mu for3863.21Yuan/mu,T1was the second by reaching3599.08Yuan/mu and T2and T4reached the lowest economic benefits,namely3575.96Yuan/mu and3465.55Yuan/mu. While From the evaluation of soil nutrients comprehensive index,we can conclude that the soil quality of T4was optimal with IQI0.657; followed by T1with IQI0.624; then followed by T3treatment with IQI0.590and T2had the lowest IQI,only0.430. From the angel of Economic and ecological benefits of each treatment,economic output and soil quality of T1was in the processing level; T2was manifested not dominant; T3economic output was optimal,but the soil quality was only better than that of treatment T2; while with the lowest economic output,T4had the optimal soil quality. For the balance of economic output and soil quality,we agree that T1treatment is the best opts.In summary,the optimization of scientific and rational evaluation of slope-Mulberry system,to improve its ecological,economic,comprehensive benefits could not only control agricultural non-point source pollution,but also could increase the productivity of land,and be good for local production. Meanwhile,theory of the underlying technology associated with the type and spatial structure of mulberry,management techniques on slopes has a great impact on Mulberry systems. In particular,depending on different factors as the terrain slope,soil depth,combined with meteorological data,how to rational design of mulberry with correlation between basic researches techniques with spacing should be further strengthened. |
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