Study On Agricultural Non-point Pollution Impact Of Different Fertilization Management In Maize Continuous Cropping Area In Northeast China

To explore the agricultural sustainable path of guaranteeing crop yield, improving fertilizer use efficiency and decreasing non-point pollution is the urgent requirement of national food security and ecological environment security. Optimized fertilization management not only can guarantee the crop yield, increase income, but also can enhance fertilizer efficiency and protect the environment. Different fertilization management have important effect on crop yield and ecological environment. In order to understand the fertilization effect on crop and mechanism on non-point pollution of different fertilization management, and further clarify the impact of different fertilization management on ammonia volatilization, nitrogen and phosphorus loss of runoff and leaching, nitrogen balance in soil- crop systems, one year(2014) outdoor and indoor simulation experiment of ammonia volatilization, two years(2013-2014) outdoor simulation experiments of nitrogen and phosphorus loss in nature rainfall condition and six years field experiment(2004-2009) were conducted with six different fertilization management : no fertilizer(CK), farmers conventional fertilization(F), soil testing and formula fertilization(R), straw returned(S), organic fertilizer mix(M) and the new type of fertilizer- controlled release fertilizer(C), on continuous maize cropping system on Black soils Northeast China. The effect of different fertilization management on maize yield, fertilizer utilization ratio and the influence law of non-point source pollution were studied, and total impact on environment pollution was evaluated by LCA model in order to find and establish optimized fertilization management with stable yield, higher efficiency, and friendly environment, furthermore, to provide theoretical basis for solving non-point pollution problem on continuous maize cropping system on Black soils Northeast China. The results were following:1. The results of different fertilization management effect on ammonia volatilization by outdoor simulation experiment in 2014 showed that in the same climate and soil conditions, the ammonia volatilization accumulation of farmer conventional fertilization was the highest, which reached 26.1 kg N/hm~2; that of straw returning fertilization and controlled released fertilization was 24.2 N kg/hm~2 and 23.88 N kg/hm~2 which were reduced by 7.1% and 8.5%, respectively, compared with farmer conventional fertilization. The ammonia volatilization accumulation of organic fertilizer mix treatment was 21.7 N kg/hm~2 which lower 16.9% than farmer conventional fertilization; that of no fertilization treatment was the smallest, reached 8.48 N kg/hm~2。It showed by indoor incubation experiment that soil moisture and temperature have significant effect on ammonia volatilization; controlled release fertilization could remarkably reduce ammonia volatilization with low temperature and soil moisture. Straw returning fertilization, controlled release fertilization and organic fertilizer mix could guarantee crop yield and decrease ammonia volatilization into the environment, compared with farmer conventional fertilization.2. The results of different fertilization management effect on nitrogen and phosphorus loss by outdoor simulation experiment in 2013 showed that the sediment amount of fertilizer application treatment was less 6%-10% than that of no fertilizer treatment; nitrogen and phosphorus loss in sediment was 7 times and 16 times than that in runoff solution. Total nitrogen load sequence of different fertilization management on the entire growth period by runoff and leaching was farmer conventional fertilization > organic fertilizer mix>straw returning>soil testing and formula fertilization, and 18.27 kg/hm~2,15.79 kg/hm~2,15.13 kg/hm~2 and 14.24 kg/hm~2, respectively, fertilizer loss rate was 2.64%,1.61%,1.33% and 1.16%, respectively. Total phosphorus load sequence of different fertilization management on the entire growth period by runoff and leaching was organic fertilizer mix>no fertilizer> farmer conventional fertilization>soil testing and formula fertilization>straw returning, 3.61 kg/hm~2,3.21 kg/hm~2,3.17 kg/hm~2,2.94 kg/hm~2 and 2.70 kg/hm~2, respectively. Soil erosion is the main reason resulting in the loss of phosphorus. Various concentration of nitrogen and phosphorus of fertilization management in runoff and leaching water samples were beyond than level of surface â…£water standard. Dissolved nitrogen(DN) is the main formation of nitrogen losses in surface runoff and leaching; Phosphorus mainly exists in the form of particulate matter. Soil testing and formula fertilization can ensure crop yield, reduce the loss of nitrogen and phosphorus, improve the utilization rate of fertilizer in high rainfall year.3. The results of different fertilization management effect on nitrogen and phosphorus loss by outdoor simulation experiment in 2014 showed that there was no soil erosion phenomenon because of less rainfall in the whole growth period. Total nitrogen load sequence of different fertilization management on the entire growth period by runoff and leaching was farmer conventional fertilization > straw returning>organic fertilizer mix> controlled release fertilization, were 3.46 kg/hm~2,3.29 kg/hm~2,2.85 kg/hm~2å'Œ 2.21 kg/hm~2, respectively, fertilizer loss rate was 0.97%,0.90%,0.71%å'Œ0.45%, respectively. Total phosphorus load sequence of different fertilization management on the entire growth period by runoff and leaching was straw returning>organic fertilizer mix > farmer conventional fertilization>controlled release fertilization>no fertilizer, were 51.45 g/hm~2,33.87 g/hm~2,33.57 g/hm~2,25.83 g/hm~2 and 9.47 g/hm~2, respectively.Nitrogen and phosphorus losses load of different fertilization management were significantly reduced compared with higher flow year(2013), the main reason is that there are no soil erosion phenomenon. The concentration of nitrogen and phosphorus in runoff and leaching solution were overweight. Dissolved nitrogen are mainly accounted for about 80-90% of the total nitrogen, in which organic nitrogen and nitrate are the main ingredients; particles phosphorus is mainly phosphorus form, inorganic phosphorus is main ingredients in the soluble phosphorus, account for about 10-30% of total phosphorus. Controlled release fertilization can ensure crop yield, reduce the loss of nitrogen and phosphorus in day year.4. The result of different fertilization management effect on crop yield, nitrogen uptake, nitrate accumulation in soils and nitrogen balance in soil-crop system by 6 years field experiment in continuous cropping system showed that, compared with farmer conventional fertilization, nitrogen use efficiency of nitrogen reduction management increased 37.9%, nitrate accumulation in soils decreased 16.2 kg/hm~2,inorganic nitrogen residue in soils reduced 19.6%, nitrogen loss and nitrogen surplus decreased 47.4% and 43.4%, respectively; moreover, nitrogen use efficiency of controlled release fertilization management increased 50%, nitrate accumulation in soils decreased 27.2 kg/hm~2,inorganic nitrogen residue in soils reduced 32.8%, nitrogen loss and nitrogen surplus decreased 75.3% and 69.3%, respectively. Both of fertilization management have no significant effect on crop yield.5. The result of assessment on different fertilization management on continuous six years maize cropping system on Black Soils by nitrogen loss estimation model and LCA analysis method showed that, optimized nitrogen reduction management could reduce ammonia volatilization, nitrous oxide, nitrogen leaching and nitrogen runoff by 17.6%, 33.7%, 44.4% and 37.7%, compared with farmer conventional fertilization, in the nitrogen loss estimation model. Total nitrogen loss of optimized nitrogen management decreased 220.4 kg/hm~2 in 6 years. Producing 1t maize, optimized management decreased energy consumption, greenhouse effect, eutrophication and acidification potential by 26.2%, 22.8%, 32.6% and 30.2%, compared with farmer conventional fertilization management. Therefore, optimized nitrogen management, which could guarantee the crop yield, reduce the impact on environment, is a kind of green and sustainable fertilizer application management.