目的 研究滴灌追氮管理对宿根蔗田土壤氮组分和N2O排放的影响，揭示影响土壤N2O通量的土壤因子。方法 以二代宿根蔗Saccharum officinarum为研究对象，在移动防雨棚内进行2个滴灌灌水量[田间持水量的70%~80%(W0.8)和田间持水量的80%~90%(W0.9)]及3种滴灌追氮比例(等氮量250 kg·hm?2，其中，N0为用作追肥的氮肥全部施用到土壤中，N5为50%土施追氮、50%用滴灌系统施用，N7为30%土施追氮、70%滴灌追氮)的田间试验。在甘蔗生长的各个时期测定蔗田土壤N2O通量、pH和氮组分含量，并分析土壤N2O通量与土壤pH和氮组分含量的关系。结果 土壤N2O通量在施用氮肥和灌水后2 d较高，其中，分蘖后期和成熟期W0.9N5处理的土壤N2O通量显著低于其他处理。W0.9条件下，分蘖后期N5处理的土壤N2O累积排放量分别比N0和N7低47.3%和11.8%，伸长后期N5处理的土壤N2O累积排放量比N7低21.5%。相同滴灌追氮比例下，土壤硝态氮含量表现为W0.9>W0.8，随着灌水量的增加，土壤硝态氮含量有所增加。在伸长初期和成熟期，W0.8 N5处理的土壤铵态氮含量比W0.8 N0高56.4%和71.8%、比W0.8 N7高68.5%和160.3%。在分蘖后期，相同滴灌灌水量下，土壤微生物量氮含量表现为N5>N7>N0，W0.8和W0.9两种灌水量下，N5处理的土壤微生物量氮含量分别较N0处理高120.0%和100%。土壤N2O通量与铵态氮含量之间呈正相关关系(r=0.313)，与硝态氮含量之间呈负相关关系(r= ?0.391)。结论 W0.9N5处理可以降低土壤N2O排放，且土壤铵态氮和硝态氮含量影响土壤N2O通量，即土壤铵态氮含量越高，土壤N2O通量越高，而土壤硝态氮含量越高，土壤N2O通量却越低。
Objective To study the effects of drip irrigation nitrogen (N) chasing management on soil N fraction and N2O emission in host cane fields, and reveal the soil factors affecting soil N2O fluxes.Method Two water drip irrigation levels of W0.8 (70%?80% of field water holding capacity) and W0.9 (80%?90% of field water holding capacity) and three drip irrigation N chasing ratios (250 kg·hm?2 of equal N) were carried out in a mobile rain-proof shelter with the second generation host cane (Saccharum officinarum) as the research object. N0 was all the N fertilizer applied to the soil (referred to as soil-applied N); N5 was 50% soil-applied N and 50% applied by drip irrigation system (referred to as drip-applied N); N7 was 30% soil-applied N and 70% drip-applied N in the field trials. Soil N2O flux, pH and nitrogen fraction content were measured at each period of sugarcane growth, and the relationship between soil N2O flux and soil pH/nitrogen fraction content was analyzed.Result Soil N2O flux was higher after two days of applying N fertilizer and water irrigation, and the soil N2O flux of W0.9N5 was significantly lower than other treatments at the late tillering stage and maturity stage. Under W0.9, the cumulative soil N2O emissions in N5 at the late tillering stage were 47.3% and 11.8% lower than those of N0 and N7, and 21.5% lower than those of N7 at the late elongation stage. Soil nitrate N content showed W0.9 > W0.8 for the same drip irrigation N rate, and increased with the increase of water irrigation. At the early elongation and maturity stage, the soil ammonium N content of N5 under W0.8 was 56.4% and 71.8% higher than those of N0, was 68.5% and 160.3% higher than those of N7. At the late tillering stage, soil microbial biomass nitrogen showed N5 > N7 > N0 under the same water drip irrigation level, and soil microbial biomass nitrogen of N5 was 120.0% and 100% higher than N0 under both water irrigation rates, respectively. There was a positive correlation between soil N2O flux and ammonium N content (r=0.313) and a negative correlation with nitrate N (r=?0.391).Conclusion W0.9N5 treatment can reduce soil N2O emissions, and soil ammonium N content and nitrate N content affect soil N2O flux, i.e., higher soil ammonium N content is associated with higher soil N2O flux, while higher soil nitrate N content is associated with lower soil N2O flux.