Study On Nutrient Release Characteristics And Environmental Effects Of A New Slow-release Urea

Slow/controlled release fertilizer is a kind of new fertilizer that nutrient release basic synchronization of crop uptake of nutrients,It is relatively low production cost and good slow release effect,make it in use process can not only improve nutrient utilization,reduce nutrient loss and reduce greenhouse gas emissions,eutrophication of water bodies of the fertilization and other environmental problems,and can also be controlled by a one-time use of lower labor costs in the process of fertilization.So environmental friendly,high nutrient utilization characteristics of new type of fertilization has a broad application prospects.This study used coal gasification urea slow-release urea for preparation of functional adsorption material production technology,probe into its nutrients through indoor simulation test modal transformation of leaching of nitrogen and ammonia volatilization loss characteristics,at the same time,with the analysis of field experiment,the soil available nitrogen nutrition and yield of corn Through this study,is expected to provide reference of matrix of slow-release fertilizer research and development and application in agriculture.The main results are listed as follows:?1?In sand leaching experiment,cumulative nitrogen leaching ratio reached 98.9%at the 2nd leaching in common urea treatment,while that in matrix-based urea treatment was 62.4%.In soil leaching experiment,leached nitrogen during the 1st-3rd leaching in matrix-based urea treatment was significantly lower than that in common urea treatment?P<0.05?,and thereafter leached nitrogen in matrix-based urea treatment were generally greater than that in common urea treatment?P>0.05?;?2?The cumulative nitrogen leaching amount in matrix-based urea treatment?144.3 mg N?had no significant difference with that in common urea treatment?146.9 mg N?.Ammonia emission peaked at the 3rd day after fertilization in both common urea and matrix-based urea treatment.However,compared with common urea treatment,cumulative ammonia emission in matrix-based urea treatment was significantly decreased by 41.6%?P<0.05?;?3?The soil culture experiment showed that the modified matrix materials had no effect on nitrogen transformation.?4?Nitrogen release characteristics could be fitted using the first-order kinetic equation,i.e.,N_t = N0_1-e^-bx.Nitrogen release rate constant?b?of SRU was 67.4%-82.6%lower than that of CU,while cumulative ammonia emission of SRU was 15.8%-39.3%lower than that of CU;?5?Available nitrogen concentration in the plough layer of maize field increased with adding proportion of functional material,and then increased leaf chlorophyll content and nitrate reductase activity in maize;?6?Slow release urea increased maize biomass and grain yield.Calculation from a polynomial model showed that the greatest plant biomass(15829 kg·hm^-2),shoot biomass(164.0 g·plant^-1),root biomass(26.9 g plant^-1)and grain yield(6769 kg·hm^-2)could be obtained in SRU treatments with 5.28%,4.80%,5.24%and 4.76%functional material,respectively.