The production and emission of N2O and influential factors in the corn growing season of loess soil

Chinese. 采用土壤平衡气室法和密闭气室法，对玉米生长期对照（不施氮肥）和施氮处理（180 kg/hm2N）黄土区土壤剖面中N2O浓度和土壤表面N2O排放通量的变化及其影响因子进行了研究。结果表明，在玉米生长期，土壤剖面中N2O主要产生于7月和8月，且60 cm土层的N2O浓度最高，10 cm土层最低；施用氮肥不仅增加了土壤剖面中N2O的浓度，而且增加了土壤表面N2O的排放通量，玉米生长期对照和施氮处理的土壤表面N2O平均排放通量分别为(10.95±4.13)和(22.41±8.69) μg/(m2•h)。对照和施氮处理土壤剖面中N2O浓度和土壤表面N2O排放通量的变化趋势相同，但施氮处理土壤剖面中N2O浓度和N2O排放通量均明显高于对照。土壤温度、水分以及土壤NO3--N 含量是土壤N2O产生和排放的主要影响因子。

English. By using soil probes and enclosed chamber methods, N2O concentration in the soil profile, N2O fluxes on soil surface and influential factors of control treatment (no fertilizer added) and fertilized treatment (applied 180 kg/hm2 N) were studied during the corn growing season of loess soil. The results showed that during the corn growing season, both N2O concentrations in soil profiles and N2O fluxes on the soil surface were mainly produced in July and August. The highest N2O concentration in the soil profile existed in the 60 cm soil layer while the lowest in the 10 cm for both treatments. The application of nitrogen fertilizer not only could increase N2O concentration in the soil profile but also raise N2O fluxes on the soil surface. The average N2O flux for control treatment and fertilized treatment were (10.95±4.13) and (22.41±8.69) μg/(m2•h) during the whole corn growing season respectively. The variation of N2O concentration in the soil profile and N2O fluxes on the soil surface for control and fertilized treatment were similar, but the values of the fertilized treatment were obviously higher than that of the control treatment. Soil temperature, soil moisture content and NO3--N contents were main factors affecting both N2O production and emission.