Study On Nitrogen Loss In The Rainfall Of Source Pollution

The agricultural nonpoint source pollution of china is widely distributed, and it is difficult to be controled, meanwhile, the use of chemical fertilizers in china is large,ranking first in the world. The excessive use of fertilizers will cause a vicious circle,like this:excessive apllication of fertilizer to fertilizer wastage and pollution of the environment, to soil structure destruction,soil fertility decilne, and to continue using the additional fertilizers, and it not only causes tremendous losses,but also creates serious environmental pollution.Based on the developed research at home and outside,this paper conducts the experimental simulation study for the impact of the rainfall on the fate of Nitrogen in the aspects of nonpoint source pollution. A simulation equipment was set up in the laboratory of the Earth Sciences and Environmental Engineering for the experimental simulation study,15operations of artificial rainfall simulation was executed in more than a month. This papers studies include the following three parts.1. Reasearch the crop Nitroge loss characteristics on the condition of the different fertilizer levels and the same rainfall. Select the urea and ammonium bicarbonate as the experimental fertilizer,cabbage as an experimental crop, and the potted plants was grown in the laboratory on the balcony,numbered respectivly1#urea,2#urea,3#urea,1#ammonium bicarbonate,2#ammonium bicarbonate,3#ammonium bicarbonate, using different intensity of fertilization,and then taking the same intensity rainfall simulation, water was sampled every two days, the NO3--N content was determined in the urea group, and the NH4+-N content was determined in the Ammonium bicarbonate group. At last, The characteristics of Nitrogen loss in the simulated experimental condditions was obtained.2. Reasearch the crop Nitroge loss characteristics on the condition of the same fertilizer levels and the same rainfall. The materials and planting patterns is same as the first group. Imposing the same amount of urea to1#urea,2#urea and3#urea, besides, imposing the same amount of mmonium bicarbonate to1#ammonium bicarbonate,2#ammonium bicarbonate and3#ammonium bicarbonate, then taking the different intensity rainfall simulation. Water was sampled every two days, the NO3--N content was determined in the urea group, and the NHU+-N content was determined in the Ammonium bicarbonate group. At last, The characteristics of Nitrogen loss in the simulated experimental condditions was obtained.3. Reasearch the crop Nitroge loss characteristics on the condition of the different fertilizer levels and the continuously different intensity of rainfall. Proved that there is a strong correlation among the amount of rainfall, fertilization and the Nitrogen loss. On this basis, the rules and characteristics of NO3--N and NH4+-N loss with rainfall changes is analysied. Taking the amount of fertilization and the impact of rainfall on the whereabouts of Nitrogen into consideration, the combined effects of rainfall on Nitrogen loss was concluded by reasonable data analysis. The result of this paper can bring some reasonable basis and help to the control of agricultural nonpoint source pollution and farmland rational fertilization.