有机无机肥配施对城郊设施甜玉米地N2O排放的影响

本文以长沙近郊设施菜地为研究对象，设置不施肥（CK）、常规施肥（CON）、30%牛粪有机肥氮+70%无机肥氮（CM）、30%鸡粪有机肥氮+70%无机肥氮（NM）4个处理，采用静态暗箱—气相色谱法监测甜玉米（Zea mays var. rugosa Bonaf.）生长季土壤氧化亚氮（N2O）的排放通量，同时测定土壤铵态氮、硝态氮、可溶性有机碳（DOC）含量和作物产量及吸氮量，探讨有机肥与化肥配施对甜玉米季N2O排放的影响。结果表明，甜玉米季表现出较高的N2O排放量，为24.6~33.6 kg/hm2。与CON处理相比，CM处理单位面积N2O累积排放量显著减少了26.9%，而NM处理减排不显著；CM和NM处理单位产量N2O排放量分别减少了35.7%和19.0%。与CON处理相比，CM和NM处理土壤铵态氮含量分别减少60.7%和50.1%，NM处理土壤硝态氮含量显著减少了40.4%， 而CM和NM处理土壤DOC含量无显著变化。随机森林模型和主成分分析结果表明，N2O排放通量与土壤铵态氮、硝态氮和DOC含量呈显著正相关，表明化肥配施有机肥能通过降低土壤无机氮供给，减少N2O产生。另外，较CK处理而言，CON、CM和NM处理的玉米产量分别增产了156.5%、191.8%和188.2%，且CM、NM处理较CON处理分别增加了13.8%和12.4%，CM的氮肥利用率相较于CON处理提高了15.2%。综上，30%有机肥+70%化肥能有效降低甜玉米地N2O排放和增加产量，且牛粪较佳。

Effect of combined application of organic and inorganic fertilizers on N2O emissions from a peri-urban protected vegetable field with sweet corn planting

To investigate the effect of combined application of organic and chemical fertilizers on N2O emissions, a typical peri-urban protected vegetable field with sweet corn planting was chose as the research object, and a field experiment was conducted with four treatments, including no fertilizer (CK), conventional fertilizer (CON), 30% cow dung organic nitrogen fertilizer + 70% inorganic nitrogen fertilizer (CM), and 30% chicken dung organic nitrogen fertilizer + 70% inorganic nitrogen fertilizer (NM). The N2O emission fluxes were measured by the static opaque chamber-gas chromatography method during the growing season, with soil ammonium nitrogen, nitrate nitrogen, and soluble organic carbon (DOC) contents as well as crop yield and nitrogen uptake also measured. Results show that the cumulative N2O emissions were much high during the sweet corn (Zea mays var. rugosa Bonaf.) season, ranging from 24.6~33.6 kg/hm2. The N2O emissions per unit yield were reduced by 35.7% and 19.0% for the CM and NM treatments, respectively, in comparison to the CON treatment. The CM treatment demonstrated a significant reduction in cumulative N2O emissions per unit area by 26.9%, while the NM treatment did not reduce N2O emissions significantly. The soil nitrate nitrogen content was significantly reduced by 40.4% in the NM treatment compared to the CON treatment, and the soil ammonium nitrogen content was reduced by 60.7% and 50.1% in the CM and NM treatments, respectively. The soil DOC contents in the CM and NM treatments did not show significantly change. N2O emissions fluxes were significantly and positively correlated with soil ammonium nitrogen, nitrate nitrogen, and DOC contents. This suggests that replacing chemical fertilizer with organic fertilizer could reduce N2O emissions by reducing the amount of available inorganic nitrogen in the soil. Furthermore, the yield of CON, CM, and NM treatments increase 156.5%, 191.8%, and 188.2%, respectively, compared to the CK treatment. The yield of CM and NM treatments increase 13.8% and 12.4%, respectively, compared to the CON treatment. Moreover, the nitrogen fertilizer use efficiency of the CM treatment increased by 15.2% compared to the CON treatment. In conclusion, the combined application of 30% organic fertilizer and 70% chemical fertilizer proved effective in reducing N2O emissions and increasing yields in sweet corn fields. Additionally, the use of cattle manure was found to be more effective.