Study on Nitrogen Migration Law in Soil from Da′an Irrigation Area under Given Irrigation and Fertilization Conditions

In order to study nitrogen migration law of soil samples from Da′an irrigation area,soil column leaching experiment using the typical soil samples collected by the project team in the area was done.Based on the irrigation and fertilization methods utilized in the area currently,the experimental project was determined.Experimental data were analyzed by using mass fraction of nitrogen at different depth of soil samples.The results show that in the same section,when ammonium and nitrate content reached the peak,its depth migrated downward gradually with the extension of time under given irrigation and fertilization conditions.The mass fraction of ammonium nitrogen in the soil gradually decreased in the migration process of nitrogen,while the mass fraction of nitrate in the soil gradually increased.Besides,the stability of the ammonium nitrogen was higher than nitrate.According to the law of ammonium nitrogen leaching losses and the accumulation of nitrate in the soil under given irrigation and fertilization conditions,the amount of the irrigation and fertilization should be controlled so as to achieve the efficient utilization of nitrogen fertilizer.