Effects Of Different Fertilizer Modes On Nitrogen Losses In Vegetable Field

Today,the point source pollution has been effectively controlled.The serious problem of agricultural non-point source pollution has become increasingly prominent.And vegetable field,one of the important land utilization types,because of its short growth cycle,high multiple cropping index and large amount of fertilizer application,has caused vegetable field nitrogen non-point source pollution quite serious by unreasonable application of nitrogen.Against the water eutrophication and the groundwater nitrate pollution caused by nitrogen non-point source pollution of vegetable fields,this study,from the perspective of the different fertilization patterns,with potted soil Chinese cabbage as the research object,explore the effects of four different fertilization modes(no fertilizer,NF;organic fertilizer,OF;chemical-organic compound fertilizer,COF;chemical fertilizer,CF)on the characteristics of nitrogen surface runoff and leaching loss and nitrogen fertilizer use efficiency by artificial simulated rainfall experiment.The main results were as follows:(1)Effects of Different Fertilization Modes on Nitrogen Runoff Loss on Vegetable Field Fertilization is the main factor leading to nitrogen runoff loss on vegetable field.It is minimum risk of nitrogen runoff loss that chemical-organic compound fertilizer,which has higher environmental benefits.The concentration of total nitrogen and nitrate nitrogen decreased with time,but the concentration of ammonia nitrogen was decreased rise and fall.The risk of nitrogen runoff losses during the rainfall in the early stages of fertilization and crop growth was extremely high.The concentration of nitrogen in runoff is positively correlated with rainfall intensity.Particulate nitrogen is the main form of nitrogen runoff loss,and nitrate nitrogen is the main form of runoff loss in dissolved inorganic nitrogen.(2)Effects of Different Fertilization Modes on Nitrogen Leaching Loss on Vegetable FieldThe mode of chemical-organic fertilizer mixed lead to less leaching loss.The overall trend of total nitrogen concentration and nitrate nitrogen concentration in leaching water under three different fertilization modes was similar basically,all rising to the peak first and then decreased to flat-lined gradually.Ammonia nitrogen leaching concentration fluctuates with time but is generally more gentle.There was a positive correlation between rainfall intensity and total nitrogen,nitrate nitrogen and ammonia nitrogen concentration in leaching solution.With the increase of rainfall intensity,the peak of total nitrogen and nitrate nitrogen leaching solution of three fertilization modes appeared ahead of time.The majority of nitrogen could be leached out in the form of soluble inorganic nitrogen such as nitrate nitrogen and ammonia nitrogen.Nitrate nitrogen was the main nitrogen form of vegetable field leaching.(3)Comparison of Nitrogen Concentration in Surface Runoff and Leaching SolutionIn this conditions,the main form of nitrogen non-point loss caused by rainfall is leaching loss,and the total runoff concentration of total nitrogen,nitrate nitrogen and ammonia nitrogen is less than that in leaching solution.(4)Effects of Different Fertilization Modes on Nitrogen Use EfficiencyAll fertilization patterns promoted the accumulation of nitrogen in the plants to varying degrees.Chinese cabbage plants under the COF treatment accumulated the most nitrogen.The nitrogen fertilizer utilization rate of chemical-organic compound fertilizer was 26.03%,which was the best in three fertilization modes.In conclusion,in the short-term vegetable cultivation period,the fertilization model of chemical-organic compound fertilizer can reduce the loss of nitrogen under the condition of high nitrogen use efficiency,thus reduce the risk of nitrogen non-point source pollution,and embark on environment-friendly,safe and efficient and sustainable agriculture production road.