The Study Of Characteristics Of Nitrogen Loss In Non-point Pollution Under Different Slope And Different Rainfall Intensity

Non-point source pollution has become the world's widespread environmental problem.Agricultural non-point source pollution is the main form of non-point source pollution.The core of the agricultural non-point source pollution problem are those the increasing of the nitrogen and phosphorus in water,eventually lead to the eutrophication of water body.Agricultural non-point source pollution has been widely valued,the research of agricultural non-point source pollution has very important significance to sustainable development and environmental protection.In this paper,design and set up the experimental plot of simulated tillage layer,and simulated the artificial rainfall by spraying system.The main research results are as follows:(1)Under the condition of rainfall intensity is moderate rain(6 mm/h)and the rainfall is 4L,design five experimental groups slope of 0,5,10,15,20 degrees.Study the nitrogen loss characteristic in surface runoff water and lower water seepage.Through the experiment conclusions as follows:? The ammonia nitrogen,nitrate nitrogen,total nitrogen concentrations of surface runoff water and lower water seepage:Slope of 15 degrees group>slope of 20 degrees group>slope of 10 degrees group>slope of 5 degrees group>slope of 0 degree group.Slope degrees from 0,5,10,15 degrees the concentrations are increase with the increase of slope,but after more than 15 degree the concentrations decrease with the increase of slope.Slope of 15 degrees is the critical value to impact the change of ammonia nitrogen,nitrate nitrogen,total nitrogen concentrations.?The ammonia nitrogen concentrations of surface runoff water and low water seepage decrease with the passage of time.From the third day to 9 days the concentrations decrease fast,From the 9 days to 29 days the concentrations gentle decrease.?The nitrate nitrogen concentrations of surface runoff water and low water seepage,from the third day to 6 days increase fast,From the 6 days to 9 days the concentrations decrease fast,From the 9 days to 29 days the concentrations gentle decrease.The characteristic of total nitrogen concentration change with time is the same with nitrate nitrogen.(2)Under the condition is slope of 10 degrees,design three rainfall conditions:rainfall intensity is light rain(2.5 mm/h),the rainfall is 2L;rainfall intensity is moderate rain(6 mm/h),the rainfall is 4L;rainfall intensity is heavy rain(12 mm/h),the rainfall is 8L.Study the nitrogen loss characteristic in surface runoff water and lower water seepage.?Through the experiment conclusions as follows:The ammonia nitrogen,nitrate nitrogen,total nitrogen concentrations of surface runoff water and lower water seepage:Heavy rain group>moderate rain group>light rain group,The ammonia nitrogen,nitrate nitrogen,total nitrogen concentrations of surface runoff water and lower water seepage are increase with the increase of rainfall intensity and rainfall.?The ammonia nitrogen concentrations of surface runoff water and low water seepage decrease with the passage of time.From the third day to 9 days the concentrations decrease fast,From the 9 days to 29 days the concentrations gentle decrease.?The nitrate nitrogen concentrations of surface runoff water and low water seepage from the third day to 6 days increase fast,From the 6 days to 9 days the concentrations decrease fast,From the 9 days to 29 days the concentrations gentle decrease.The characteristic of total nitrogen concentration change with time is the same with nitrate nitrogen.(3)The concentrations of ammonia nitrogen,nitrate nitrogen and total nitrogen in surface runoff were lower than those in the lower water seepage under different rainfall conditions and different slope conditions.(4)Under the condition of rainfall intensity is moderate rain(6 mm/h)and rainfall is 4L,design five experimental groups slope of 0,5,10,15,20 degrees.The ammonia nitrogen,nitrate nitrogen,total nitrogen concentrations of surface runoff water and lower water seepage are separately measured,study the ammonia nitrogen,nitrate nitrogen,total nitrogen concentrations relationship characteristic in surface runoff water and lower water seepage.The whole process of the experiment the concentrations of total nitrogen is the biggest of all.First few days the concentrations of ammonia nitrogen higher than the nitrate nitrogen,after the concentrations of nitrate nitrogen is higher.