Comparison Of Active Nitrogen ?N₂O,NH₃,NO₃^--N? Losses Among Different New Nitrogen Fertilizers Treatments In Cropland

In order to solve the problem lying in food demand,resources shortage and environment protection,we need to reduce the nitrogen loss and environment risk while improving nitrogen use efficiency and ensuring high crop productivity in the current agricultural sustainable development.The focus about the research of new type nitrogen fertilizer,currently as the key point of future study and marketing is on how to improve nitrogen use efficiency and the research of nitrogen loss in a single way.The synchronization research of nitrogen loss through different ways about new type of nitrogen fertilizer applied in farmland is rarely reported,especially system comparison about the loss of reactive nitrogen from different types of new nitrogen fertilizer under the same soil and climate conditions.Thus it is necessary to conduct the related research and to understand the nitrogen loss characteristics of different types of active fertilizer;the results will helps to provide data support for the reasonable application of nitrogen fertilizer and the popularisation of new type of fertilizer in China's farmland,and also helps to provide scientific basis for the policy decision about how to mitigate soil acidification,water eutrophication and greenhouse gas emission.To investigate the effects of nitrogen fertilizer on ammonia?NH₃?volatilization,nitrous oxide?N₂O?emissions,nitrate?NO₃^--N?leaking and NO₃^--N runoff from the summer maize,direct-seeded rice and winter wheat field,a series of field experiment were conducted in this study.Seven treatments included a control without fertilizer?CK?,conventional fertilization?compound fertilizer + urea,CF?and five new varieties of nitrogen fertilizers such as urea ammonium?UA?,stability urea with dicyandiamide and hydroquinone?UHD?,sulfur coated urea?SCU?,urea formaldehyde compound fertilizer?UF?and organic fertilizer?OF?.The nitrogen release characteristics of different nitrogen fertilizers were different.This determined the difference of N losses after application in different ways.During the maize growing season,in addition to SCU,no significant difference was found with regard to N₂O-N emission,NH₃-N volatilization,nitrate leaching and runoff among all fertilizers treatments?p>0.05?.In the mean level,all new types of nitrogen fertilizer treatments except for UA decreased the NH₃-N volatilization in comparison with CF,while all treatments had no significant difference in N₂O-N emissions?p>0.05?.For nitrate leaching,only OF reduced nitrate loss.However,only UA significantly reduced nitrate runoff?p<0.05?.We concluded that the application of nitrogen fertilizers could cause N losses through N₂O-N emission,NH₃-N volatilization,nitrate leakage and runoff.The total nitrogen loss rate of different treatments was 18.7%?31.7%.During the direct-seeded rice growing season,the other nitrogen fertilizers had no significant effect on N₂O-N emission in comparison with CF?P>0.05?,only UA and SCU treatments decreased by 6%and 11%of the value.In addition to UA and OF,UHD,SCU and UF treatments could significantly reduce the farmland NH₃-N volatilization by 18%?36%?p<0.05?.Compared with CF treatment,nitrate leaking had no significant difference among all treatments?p>0.05?.The total nitrogen loss rate of N₂O-N emission,NH₃-N volatilization and nitrate leakage from different treatments was 10.0%-18.6%,which resulted from nitrogen fertilizers application in rice season.During the wheat growing season,only CF significantly decreased the N₂O-N emission when compared to CF treatment?p<0.05?,while application of other nitrogen fertilizers had no significant effect on N₂O-N emission?p>0.05?.Besides,UHD,SCU,UF and OF treatments had significant reduction effect on NH₃-N volatilization?p<0.05?.However,UA treatment had no significance on NH₃-N volatilization in comparison with CF treatment?p>0.05?.The total gaseous nitrogen loss rate of NH₃-N volatilization and N₂O-N emission which caused by nitrogen fertilizers application in wheat season was 9.0%?15.4%.To further calculate the nitrogen losses and yield indicated that UHD and UF showed priorities in reducing nitrogen losses and increasing economic benefit in rice/wheat planting among all treatments.