Research On The Creation And Application Of New Efficient Nitrogen Fertilizer

In recent years,under the guidance of China’s weight-loss policy,the utilization rate of nitrogen fertilizer has increased from about 25%to about 43%,but it is still far lower than the European and American levels（54%in Europe,65%in the United States,68%in Canada）and the world average level（58%）.At present,the application of enhanced nitrogen fertilizer is one of the effective ways to improve the efficiency of nitrogen fertilizer in agricultural production at home and abroad.NBPT and NPPT are the most widely used urease inhibitors.However,there are still some problems in the application of NBPT and NPPT,such as fast degradation rate,low effectiveness and uneven addition.Therefore,in this study,wet sandizing process was adopted to prepare a new formulation of microcrystalline suspension agent with urease inhibitors n-butylphosphotriamine（NBPT）,n-propyl phosphotriamine（NPPT）and additives as materials.New type of efficient nitrogen fertilizer has been prepared,such as NBPTSC,NPPTSC and NBPTSC+NPPTSC（7:3）,combined with large-particle urea.Through fertilizer preparation experiment,laboratory culture experiment and field verification experiment,the stability of fertilizer was clarified,the nitrogen transformation characteristics of new efficient nitrogen fertilizer under different soil types were clarified,and the mechanism of increasing yield and improving nitrogen utilization rate of maize on black soil was also clarified,which provided a theoretical basis for the development and rational application of new efficient nitrogen fertilizer.The main research results are as follows:（1）Through the determination and analysis of the performance of the new synergistic nitrogen fertilizer,the fertilizers of each treatment have good stability.The wet sanding process should be more than 8 hours to grind the NBPT to less than 5 microns homogeneous dispersion system;The mixed use of a+b will obtain better dispersion effect,which is conducive to the film forming stability of fertilizer.The degradation rate of NBPT was 44.6%on the 30th day of the new efficient nitrogen fertilizer stored at room temperature,while that of the traditional coating treatment was 56.9%on the 7th day,which effectively slowed down the degradation of NBPT in the fertilizer and theoretically could achieve the expected effect of slow nutrient release.（2）The new synergistic nitrogen reduces the conversion of amide nitrogen to ammonium nitrogen in soil by inhibiting urease activity for a long time.The treatment of different fertilizers can further reduce the content of nitrate in soil by inhibiting the concentration of NH₄⁺,inhibit the hydrolysis of urea by controlling the proportion of inorganic nitrogen in soil,and improve the utilization rate of fertilizer.The urease activity of new nitrogenous fertilizer treatment was significantly lower than that of urea treatment,and the inhibitory rate of urease activity was0.25%（NBPT+NPPT）>0.50%NBPT>0.25%NBPT.（3）The new efficient nitrogen fertilizer could significantly increase the yield of maize.Through the analysis of two years of experiments,under each nitrogen application treatment,the number of grains per ear in urea treatment was significantly higher than that in urea treatment in terms of yield and composition,and showed a positive correlation with the concentration of urease inhibitor,corn yield increased by 19.9%-24.01%.（4）The new efficient nitrogen fertilizer can significantly improve the nitrogen use efficiency.The analysis of ammonia volatilization data showed that adding urease inhibitors could significantly reduce the accumulation of ammonia volatilization.By inhibiting the hydrolysis of urea,that is,the conversion of amide nitrogen to ammonium nitrogen,the concentration of NH₄⁺in soil was lower.The analysis of the accumulation of inorganic nitrogen shows that the low concentration of NH₄⁺in soil will lead to the decrease of NO₃^-concentration,and the leaching effect of soil will be reduced.As a result,plant nutrient uptake increased and plant nitrogen uptake increased by 26.5-40.6kg·hm^-2.The application of enhanced nitrogen fertilizer containing urease inhibitor significantly increased the nitrogen utilization rate by 9.5-13.9%.To reduce nitrogen loss and residue by 13.1-15.7%.