Effect of stubble incorporation and nitrogen fertilization on denitrification and nitrous oxide emission in an irrigated maize soil

Acetylene inhibition method was used to study effects of stubble incorporation and nitrogen fertilization on denitrification and N2O emission in an irrigated maize soil.Stubble management was designed as stubble incorporation and stubble burn.Nitrogen fertilizer was applied with 5 rates: 0,100,200,300,400 kg/ha.Samples were taken after experiment has been set 4 years.Fresh soils were incubated at 85% WFPS(water filled pore space) with 1 kPa or no C2H2 for 8 d,and N2O emission was measured during incubation.Results from variance analysis indicated that N fertilization rate,stubble incorporation and their interaction had profound effect on denitrification rate and N2O flux.Compared with stubble burn,stubble incorporation stimulated denitrification and N2O emission at the beginning of incubation under no and low fertilization rate,which result mean N2O flux of incubation period was increased.However,the denitrification rate and N2O emission of stubble incorporation were higher than that of stubble burn under high fertilization rate.Ratio of N2O/N2 from denitrification was decreased by stubble incorporation.