【摘要】 在长期定位施氮试验条件下研究了不同施肥处理的土壤Ｎ素平衡、土壤Ｎ库容量、ＮＨ３挥发量、ＮＯ３Ｎ淋溶量以及Ｎ素循环强度的变化。从５ａ（年）１０茬蔬菜的Ｎ素施入及携出累计量计算，除对照外，Ｎ素平衡强度最高为２６９．６％（Ａ１Ｂ１），最低为４９．４％（Ａ３Ｂ３），平均为１６２．５％。Ｎ素的盈亏量与Ｎ库容量相关显著（ｒ＝０．６５９９）。土壤的ＮＨ３挥发量及ＮＯ３Ｎ淋溶量随施Ｎ量的增加而加大。连续多年施用高量有机肥和Ｎ素化肥条件下，ＮＨ３挥发和ＮＯ３Ｎ淋溶几乎是两条同等重要的Ｎ素损失途径，Ｎ素循环强度高；连续多年施用大量Ｎ素化肥而不施有机肥条件下，ＮＨ３挥发是Ｎ素损失的主要途径，ＮＯ３Ｎ淋溶损失次之，Ｎ素循环强度低；长期不施肥的处理Ｎ素循环强度极低，土壤中Ｎ素严重亏缺。高投入、高输出的高肥菜田Ｎ素损失多，土壤中Ｎ素富集量增多，应控制Ｎ素化肥用量，适当降低Ｎ素循环强度；低投入、低输出的瘠薄菜田需增加有机及无机Ｎ素的投入，增强Ｎ素循环强度，以提高蔬菜产量。更多还原

【Abstract】 Under experiment of long term,fixed position N application nitrogen balance,capacity of N reservoir in soil,amount of NH 3 volatilization and NO 3 N leaching and intensity of N cycle were investigated. By calculating sum total of profit and deficit to determine intensity of N balance,the maximum N balance intensity was 269.6%{A 1B 1},the minimum was 49.4%{A 3B 3},average was 162.5%. There was significant corre llation between amount of profit and deficit of N and capasity of N reservoir{r=0.6599 *}. The amount of NH 3 volatilization and NO 3 N leaching in soil were increased in accordence with amount of N application. They were main ways of N loss when large amount of organic and inorganic fertilizer were applied yearly,intensity of N cycle was high while the loss of NH 3 was primary and the NO 3 N leaching secondarily under continual yearly application of N chemical fertilizer without applying organic fertilizer,intensity of N cycle was low. There was serious N deficient in non fertilizing treatment,intensity of N cycle was very low. It is recommended to control the amount of N application in ‘high input and high output’ vegetable field,where a large amount of N was accumulated the intensity of N cycle decreased. Both organic and inorganic N fertilizer should increase in ‘low input and low output’ vegetable field in order to increace yield of vegetable crops and intensity of N cycle.更多还原