秸秆还田对灌溉玉米田土壤反硝化及N_2O排放的影响

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

运用乙炔抑制技术研究了不同施氮水平下秸秆还田对灌溉玉米田土壤反硝化反应和氧化亚氮(N2O)排放的影响。结果表明,土壤反硝化速率及N2O的排放受氮肥施用、秸秆处理方式及其交互作用的显著影响。与秸秆燃烧相比,不施氮或低施氮水平时,秸秆还田可刺激培养初期反硝化反应速率及N2O排放,增加培养期间N2O平均排放通量;高施氮水平时,秸秆还田可降低反硝化反应速率及反硝化过程中的N2O排放。秸秆还田可降低反硝化中N2O/N2的比例。

Acetylene inhibition method was itrification and N2O emission in an irrigated used to study effects of stubble incorporation and nitrogen fertilization on denmaize 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.