Research Of Nitrogen Fertilizer Whereabouts And Balance In Winter Wheat And Summer Maize Rotation System

Nitrogen isotope tracer technique was used to research influence of the different nitrogen application on nitrogen absorption and utilization, nitrogen retention and nitrogen loss, the balance of nitrogen in soil, maize and wheat yield. The aim was to reveal the rule of nitrogen whereabouts and determine reasonable fertilize application. At the same time, in order to promote application of new type fertilizers, increase crop yield and reduce environmental pollution, the research explored effects of humic acid nitrogen fertilizer on corn and wheat yield, nitrogen absorption and utilization, and nitrogen distribution and loss in soil, and the balance of nitrogen in soil. The main results were as follows:1. Application of nitrogen fertilizer can significant improve corn and wheat yield. When application of N112.5 kg/ha-N337.5 kg/ha, the corn yield increased by 10.5%-30.1%, and wheat yield increased by31.2%-89.6%, when application of N225kg/ha, corn and wheat yield were highest. The nitrogen utilization efficiency of corn and wheat were 16.7%-32.3% and20.8%-30%, respectively.2. In corn, the nitrogen absorbtion amounts from the fertilizers occupied by 18.7%-25.5%, in wheat, the nitrogen absorbtion amounts from the fertilizers occupied by 29.1%-46.4%. When application of N112.5 kg/ha-N337.5 kg/ha, in corn, Fertilizer nitrogen and soil nitrogen ratio were 0.23-0.34, in wheat, Fertilizer nitrogen and soil nitrogen ratio were 0.41-0.87, and with the increase of nitrogen fertilizer, the nitrogen amounts from the fertilizers increased gradually.3. In corn season, nitrogen fertilizer residual ratio in soil were 31.6%-48.5%, in wheat season, nitrogen residual ratio in soil were38.4%-54%, and with the increase of nitrogen fertilizer, Soil inorganic nitrogen content significantly increased, the main residual was in 0-20 cm soil, then was in 40-60 cm.4. In corn season, nitrogen fertilizer loss rate was 19.2%-51.7%, and when nitrogen fertilizer increased N112.5kg/ha, nitrogen fertilizer loss rate would increase 16.3%. In wheat growing period, nitrogen fertilizer loss rate was 16.6%-40.8%, when nitrogen fertilizer increased N112.5kg/ha, nitrogen fertilizer loss rate would increase 12.1%. nitrogen leaching and other ways were the main way of all nitrogen lost way, then was the ammonium nitrogen volatilization. In corn season, ammonium nitrogen volatilization was mainly concentrate in first 11 days after fertilization; in wheat season, after first fertilization, ammonium nitrogen volatilization was mainly concentrate in first 10 days, the second fertilization, ammonium nitrogen volatilization was mainly concentrate in first 7 days.5. In a year, nitrogen fertilizer residual ratio in soil was 35.0%-51.3%, crop absorption ratio was 18.8%-30.9% and other nitrogen fertilizer were lost in different way. When we fertilization soil total nitrogen content would significantly increase in 0-20 cm. When amount of nitrogen fertilization was 675kg/ha, soil total nitrogen content would significantly increase in 0-60 cm. When we increased nitrogen fertilization, soil nitrogen surplus quantity would increase, significantly, meanwhile, Nitrogen fertilizer could significantly increase the amount of soil nitrogen mineralization, but it was reduced when we increase nitrogen fertilization. In this experiment, we were fitting some best fertilizer amount, in corn season it was 248.4 kg/ha, in wheat season, it was 265.0 kg/ha and the whole year of the best environmental protection fertilizer rate were 382.0 kg/ha-510.0 kg/ha.6. In same amount of nitrogen fertilizer, the yield of corn of urea activated humic acid fertilizer and conventional mixing humic acid fertilizer were increased by26.8% and 12.7%, respectively, the yield of wheat increased by50.5% and 19.2%, respectively; fertilizer utilization ratio of corn was increased 10.8% and 6.8%, respectively, fertilizer utilization ratio of wheat was increased by22.7% and 8.6%, respectively. Application of the activated humic acid fertilizer and conventional mixing humic acid fertilizers compared with common urea: in corn season, nitrogen fertilizer residue ratio increased by12.5% and 7.5%, respectively, in wheat season, there no significant increase, in corn season, nitrogen loss ratio was reduced by18.3% and 10.9%, respectively, in wheat season, nitrogen loss ratio was reduced by20.0% and 6.3%, respectively. Humic acid fertilizer can significantly increase ammounium nitrogen volatilization, but can significantly reduce nitrogen leaching and retard nitrogen fertilizer move to deeper soil layer, humic acid can increased crop absorption soil nitrogen. Active humic acid fertilizer would be better than conventional humic acid fertilizer.7. In a year, the same amount of nitrogen fertilizer, nitrogen fertilizer retention ratio of urea activated humic acid fertilizer and conventional mixing humic acid fertilizer were increased by4.9% and 2.8%, respectively, nitrogen fertilizer utilization ratio were increased 14.3% and 6.0%, respectively, nitrogen fertilizer loss rate were reduced by19.1% and 8.6%, respectively. Application of humic acid can significant increase soil nitrogen surplus and soil nitrogen mineralization.