中文摘要：

以亚热带湿热地区红壤性旱地（SU），灌丛（GB），林地（QF）为研究对象，通过在30℃和60％WHC水分条件下，35d的培养试验，研究了外源铵态氮输入对土壤N2O排放的影响。结果表明，对于pH较高的土壤Su（pH=6．27），施用硫铵、尿素和碳酸氢铵后，硝态氮累积量和N2O排放量均高于未施氮的处理，且随施N量增加而增加。对于酸性土壤GB（pH=4．82）和QF（pH=4．46），施用硫铵明显地抑制硝化作用，但却极大地促进N2O排放；施用尿素和碳酸氢铵对硝化作用有微弱的促进作用或无明显的影响，N2O的排放则略低于对照或无明显差异。酸性土壤中，加入不同类型的氮肥后，N2O排放量与硝态氮含量的比例与加入氮肥后测定的土壤pH具有显著的负相关关系。氮肥品种影响N2O排放量与硝态氮产生量比例的机理值得进一步研究。

英文摘要：

Effect of application of ammonium-based N （NH4^＋ ） on N2O emission was investigated in typical subtropical soils in China. Soil samples, collected from upland crop field （SU） , brush-land （GB） and forestland （QF）, were incubated with temperature kept at 30℃ and soil moisture at 60% of the water hold capacity （WHC） for 35 days after addition of ammonium sulphate, urea, and ammonium bicarbonate, separately. Each type of N fertilizer had three different application N rates 0, 100, and 250 mg kg^-1. Results indicate that in SU soil （pH = 6.27）, both nitrification and N2O emission were stimulated by addition of ammonium sulphate, urea and ammonium bicarbonate. Net nitrification and N2O emission increased with the fertilizer application rate. In acid GB （pH = 4. 82） and QF soils （pH = 4.46） , addition of ammonium sulphate inhibited nitrification, but dramatically stimulated N2O emission; addition of urea and ammonium bicarbonate slightly stimulated nitrification, but slightly inhibited N2O emission or showed no effect on both. Significant negative correlation was observed between the ratio of N2O emission to net nitrification in acid soils treated with different forms of N fertilizers and the soil pH measured immediately after addition of N fertilizer. Mechanisms of the effects of different forms of N fertilizers on ratio of N2O emission to net nitrification need to be further investigated.