Characteristics Of Non-point Source Pollution Output In Surface Under Different Lands Utilization Pattern In Watershed In Jianshan River

Through observation of non-point sources pollution output regularities in small watershed in jianshan river, Chengjiang,Yuxi city. This study goal to obtained non-point source pollutants on different land use patterns through the runoff plots observation, thus discovers the best land utilization way in this watershed, provide basic data for ecology restoration in this watershed. The result showed that:(1) Total amount of runoff in 2006 was 1.60 times of planted forest, 12.45 times of secondary forest, and 5.52 times of shrub-grassland. Sediment production at farmland was bigger than other lands use pattern, it was respectively 8.41, 53.06, times of planted forests, natural secondary forests, and 41.90 times of shrub-grassland.In 2007, total amount of runoff at farmland was 318.16mm, was respectively 5.32 times, 24.76 times and 19.66 times of planted forest, shrub-grassed and secondary forest; The soil erosion quantity at farmland was 5156.45 t/km2, compared to the farmland, the secondary forest and shrub-grassland separately reduced soil erosion quantity 99.08% and 99.28%; Compared to the planted forest, the secondary forest and shrub-grassland reduced soil erosion quantity 52.46% and 62.50%.(2)On the whole view, the density of total phosphorus in shrub-grassland in the beginning of june was higher than secondary forest and shrub-grassland, planted forest was the smallest. At the end of june and in july, total nitrogen density output were followed as shrub-grassland, farmland and the secondary, planted forest was the smallest one. Total nitrogen density output were bigger at farmland and shrub-grassland, and smaller at the secondary and planted forest in august and september.Total nitrogen density output in runoff in june at the farmland was the biggest one, followed as shrub-grassland and the secondary forest, and planted forest was the smallest one. In july, august and september, total nitrogen density output were bigger at the secondary and shrub-grassland, and smaller at farmland and planted forest.The ammonia nitrogen density at farmland and planted forest were bigger than at shrub-grassland and the secondary forest, the higher the vegetation coverage, the smaller density of ammonia nitrogen loss in runoff. COD output at the secondary forest and planted forest were bigger than at farmland and shrub-grassland.(3)The total nitrogen, total phosphorus and ammonia nitrogen output in the runoff in 2006 and 2007 in the farmland was the biggest, and followed the planted forest, shrub-grassland and secondary forest was the smaller. In 2006 COD output was followed as farmland, planted forest, shrub-grassland and the secondary forest, in2007 COD output was followed as farmland, planted forest, shrub-grassland and the secondary forest.(4)The total nitrogen and total phosphorus output in the erodied sediment in 2006 in different lands use pattern were orderly followed as farmland, planted forest, shrub-grassland and secondary forest. Phosphorus output in farmland was 32.4 times of shrub-grassland, total nitrogen output in farmland was 34 times of shrub-grassland; The available nitrogen and phosphorus were followed as farmland, planted forest , secondary forest, shrub-grassland. Available phosphorus output in farmland was 50.5 times of shrub-grassland and available nitrogen output in farmland was 40 times of shrub-grassland.Total nitrogen, total phosphorus, available nitrogen and available phosphorus output in the erodied sediment in 2007 in the different lands use pattern were orderly followed as farmland, planted forest, secondary forest, shrub-grassland. Total nitrogen output in farmland was 71.4 times of shrub-grassland, available nitrogen in farmland was 76.9 times of shrub-grassland; phosphorus output in farmland was 66.7 times of shrub-grassland, available phosphorus output in farmland was 5337.5 times of shrub-grassland; But the difference of total phosphorus output between shrub-grassland and secondary forest was not very big, output in secondary forest was 1.33 times of shrub-grassland.(5)The erodied sediment was capable to enrich nutrient, total nitrogen enrichment ratios in different lands use pattern orderly followed as shrub-grassland, farmland, planted forest and secondary forest, available nitrogen enrichment ratios followed as secondary forest, shrub-grassland, planted forest and farmland; Total phosphorus enrichment ratios followed as secondary forest, farmland, shrub-grassland and planted forest, available phosphorus followed as secondary forest, planted forest, shrub-grassland and farmland; Available potassium enrichment ratios followed as shrub-grassland, the secondary forest , planted forest, farmland.(6)Total nitrogen in surface soil has the inverse correlation relations with the nitrogen output in the runoff and the sediment. Correlation coefficient of total nitrogen content in soil with ammonia nitrogen in runoff was 0.66, but both correlation coefficient of total nitrogen and available nitrogen output in the sediment with runoff were bigger than 0.95. Correlation coefficient between available nitrogen in surface soil with the ammonia nitrogen was 0.37, so nitrogen loss with runoff was bigger than sediment. Phosphorus in the surface soil with phosphorus output in the runoff and the sediment was being related, total phosphorus correlation coefficient between the surface soil and the runoff was 0.7, but the phosphorus correlation coefficient is bigger than 0.99 with the sediment, Compared with nitrogen, the surface soil phosphorus was more easily to be lost with the runoff activity, and the phosphorous output was mainly connected with sediment, particularly for the available phosphorus. The relevance of surface soil nutrient with non-point source pollution output in sediment were bigger than in the runoff, therefore erosion sediment caused bigger non-point source pollution.(7)Through correlation of the amount of runoff and sediment with total nitrogen and phosphors output in runoff and in sediment obtains: The relevance was extremely remarkable between runoff amount and sediment amount. Correlation coefficient of total nitrogen output in the runoff with runoff amount was bigger than phosphorus output in the runoff, so total nitrogen loss with the runoff was bigger than sediment; Correlation coefficient of total nitrogen and total phosphorus output with the sediment was bigger than with the runoff, total phosphorus's correlation coefficient achieves 1.000 with the sediment.