北京地区潮土表层中NO3--N的转化积累及其淋洗损失

本试验利用渗滤池设施，采用化学分析和同位素技术相结合的方法研究了北京地区潮土表层中施用氮肥后ＮＯ３＾－－Ｎ转化积累及其１３０ｃｍ土体的淋洗状况。常规分析结果表明，在春小麦和夏玉米的生育前期可以观察到氮素明显地向ＮＯ３＾－－Ｎ的转化积累，其强度随尿素施用量的增加而明显增加，而尿素、硝铵、硫铵等不同氮肥品种处理之间有差异但大多不显著。同时夏玉米期间转化积累作用比春小麦期间强烈。＾１５Ｎ标记试验结果表明

NO3--N TRANSFORMATION ACCUMULATION AND LEACHING LOSS IN SURFACE LAYER OF CHAO-SOIL IN BEIJING

In lysimeters,the transformation and accumulation of NO₃^--N in surface layer and its leaching loss out of 130cm solum column in chao soil in Beijing were studied by the routine analysis methods in combination with isotopic technique.The results showed that N transformation to NO₃^--N could be observed during the earlier growth stage.The significant differences existed among the treatments applied at 3 rates of urea but could not be found among the those with 3 kinds of N fertilizers. And the transformation to NO₃^--N was less strong during spring wheat growtk period than during summer corn growth period.Meanwhile immobilization and uncounted loss of fertilizer N could occur.NO₃^--N could be leached ont of 130cm soil body during rainy season with more than l Omg NO₃^--N/L in the fertilized lysimeters where the mean NO₃^--N content might be np to 33 mg/L.And NO₃^--N leaching loss was significantly correlated to the precipitation.However,the total leaching loss rate of fertilizer N was not high.