| 摘要: |
| 用田间原位密闭气室法和乙炔抑制原状土柱培养法，研究了蔬菜地不同施氮量下N2O的逸出量。结果表明，在一定施氮量范围内，N2O通量随施肥量的增加而上升；除最高施肥量（N450）外，N2O占（N2＋N2O）的比率随施肥量的增加而增加。在施肥水平低时，氮素的损失以N2为主，当施肥量高于300kg/hm2后，则以N2O为主。2m土体中NO3-N分析结果表明，试验结束时对照和N450处理土壤剖面中有NO3-N累积，其余各个处理氮素都存在一定程度的损失，其中损失量最大的是N150处理，与N2O逸出量的趋势相一致。N2O逸出量占肥料N总用量的0.15％～0.66％，肥料逸出量占土壤N2O总逸出量的39.0％～70.3％，且在施氮水平低于N300以下时，N2O逸出量有随施肥量增加而上升的趋势。 |
| 关键词: N2O逸出量 氮肥施用量 氮素损失 |
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| 基金项目:中国瑞典国际合作项目资助；农业部重点科研计划项目(95农-03-01-03)；西北农林科技大学重点资助项目 |
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| N2O losses from vegetable field of applying different amounts of NO3-N |
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| Abstract: |
| By using inclosed chamber method and C2H2 inhibition intact soil cores method,the field experiment and lab incubation test were carried out on the fallow vegetable field after applying different amount NO3-N to study N2O losses.The results show that N2O flux increases with the increase of applying NO3-N amount except for the treatment N450,the ratio N2O/(N2O+N2) also has the same trendency.At the lower NO3-N rates,gaseous nitrogen losses will be N2.Whereas for the higher NO3-N amount,the losses will be N2O.The highest N losses will take place at N150 lever.Both the field results and caculation of NO3-N losses from 2 m soil profile have the similar conclution.N2O emission amount is only about 0.152%-0.655% of total applied N,and the emission from fertilizer is about 39.0%-70.3% of total soil emission.The natural N2O emission of test soil is 1.876 kg/(hm2·a). |
| Key words: N2O flux N application amount N losses |
