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对陕西关中不同地区农田土壤测定结果表明 ,微生物体氮是土壤有机氮库的重要组成部分 ,占土壤全氮的 0 .38%～ 2 0 .55%,平均为 6.80 %。土壤微生物体氮具有显著的分异性 ,表现为不仅具有显著的水平变异性 ,也存在明显的垂直分异性 :随着土层深度增加 ,微生物体氮下降 ,层次间的这种差异十分显著。在耕层 ,土壤微生物体氮与土壤有机质间有密切的正相关关系 ,而在下层它们之间的相关性并不明显 ,这一结果表明 ,耕层土壤有机质是影响土壤微生物体氮的一个主要因子 ;而在耕层以下 ,可能还存在着比有机质更显著影响微生物体氮的其它因子
The results of soil test in different areas of Shaanxi Guanzhong showed that microbial nitrogen was an important component of soil organic nitrogen pool, accounting for 0.38% ~ 20.55% of the total soil nitrogen, with an average of 6.80%. Nitrogen of soil microbial biomass was significantly different, showing not only significant horizontal variability but also obvious vertical differentiation. With the increase of soil depth, microbial nitrogen decreased and the difference between layers was significant. In topsoil, there is a close positive correlation between soil microbial biomass nitrogen and soil organic matter, but the correlation between them is not obvious. The results show that soil organic matter in topsoil is one of the main factors affecting soil microbial nitrogen Factor; and below the tillage, there may be other factors that affect the nitrogen of the microorganism more significantly than the organic matter