Effects of urea-formaldehyde fertilizer(UF) on N_2O emission and nitrogen balance in soil

【Objective】The effects of urea-formaldehyde fertilizer(UF)on N_2O emission and N fate and balance in soil were studied to improve its practical application.【Method】In September to December2013,micro-lysimeter and static closed chamber was adopted to study the effects of UF on N_2O emission,leaching loss,nitrogen(N)residual in soil,N uptake and other apparent losses under three rotations of continuous plant of different leaf-vegetables(Chinese cabbage,flowering cabbage,and mustard).The treatments included three UF levels(UF1,UF2,and UF3 with active indexes(AI)of 50.8%,67.4%,and83.3%),urea and UF blended with urea,splitting application of urea,and no nitrogen treatment.【Result】Compared with one-time application of urea,one-time application of UF,UF blended with urea,and splitting application of urea significantly reduced N_2O emission peak values and cumulative values.Gaseous nitrogen losses from N_2O emission were in the order of urea(one-time application)UF blended with urea(one-time application)urea(splitting application)and UF(high AI,one-time application)UF(medium and low AI,one-time application).Gaseous nitrogen losses from N_2O emission of UF treatments were 2.32 to 4.40g/m2,which were 33.1%to 62.9%of the corresponding data of the urea treatment.The N residual in soil of UF treatments was more than 45% of total N applied,32.1% to 34.0% higher than the urea treatment.The N leaching losses and the other apparent N losses of the UF treatments were decreased by32.6%to 54.0% and 52.4% to 83.9%,respectively.Plant N uptake with one-time application of UF equaled to that with urea splitting application,but was significantly greater than that with one-time application of urea.【Conclusion】The application of UF significantly increased N uptake and N residual in soil and reduced N leaching loss,N_2O emission,and other N losses.Utilization of UF is an effective measure to protect environment and increase nitrogen use efficiency.