Effects of nitrogen fertilizer and DCD application on nitrous oxide emission from soil during expand fruit stage and tomato yield

Effects of nitrogen fertilizer and DCD application on nitrous oxide(N2O) emission from soil during the expand fruit stage and tomato yield in greenhouse were studied with the traditional fertilization treatment as the control.The results illustrated that N2O emission flux and total N2O emissions were decreased significantly after application of DCD.During the first and second fertilization,total N2O emissions in traditional fertilization treatment were 15.30 and 48.18 kgN/hm2,respectively.However,the total N2O emissions in traditional fertilization with DCD treatments(DCD 5%,DCD 10%,DCD 15%,DCD 20%) and optimized fertilization with DCD treatment were decreased to 8.56,6.53,5.16,3.92,3.38 kg/hm2,and 36.33,26.38,11.61,12.49,7.94 kg/hm2,respectively.The N2O emission factors were 0.11% and 0.35% during the first and second fertilization in traditional fertilization treatment,while the N2O emission factors in traditional fertilization with DCD treatments(DCD 5%,DCD 10%,DCD 15%,DCD 20%) and optimized fertilization with DCD treatment were decreased to 0.06%,0.05%,0.04%,0.03%,0.02% and 0.26%,0.19%,0.08%,0.09%,0.06%,respectively.Furthermore,the application of DCD could also improve the tomato yield significantly.The tomato yields in traditional fertilization with DCD and optimized fertilization with DCD treatments were increased by 38.90% and 38.38%,respectively,which showed a better yield-increasing effect.Overall,the optimized DCD treatment not only reduced soil N2O emissions but also increased tomato yields significantly,which offered the best economic benefit and environmental benefit.