流动注射法与碱解扩散法测定土壤有效氮的比较

采集全国20个地区20个土壤样品,用2 mol/L KC l浸提后,分别用流动注射分析仪和碱解扩散法测定样品的速效氮（NH4＋-N）含量及回收率。结果表明,2种方法的回收率均在95.0%~105.0%,可见,2种测定方法的精确度和精密度是一致的。但由于提取方法不一致,导致所测速效氮（NH4＋-N）含量相差很大,但是用流动注射分析仪测定速效氮也能反映土壤中氮含量的变化,其结果与作物吸收氮量和作物产量是否有很好的相关性还有待于进一步研究。

Comparison of Soil Available Nitrogen Concentration between Flow Injection Method and Alkali-diffusion Method

After 20 soil samples collected from 20 regions in China were extracted with 2 mol/L KCl,the flow injection method and alkali-diffusion method were employed to analyze the available nitrogen(NH4+-N) concentration in the soils,respectively.The results showed that the recoveries of two methods were all among 95.0%-105.0%,although these suggest that the precision and accuracy of the analysis methods were consistent,the use of different extracting methods generated the great differences of available nitrogen content,and the determination of available nitrogen content by using flow injection method could also reflect the change of N content in soil;moreover,whether there were good correlation between the results of changes in crop absorption of nitrogen and crop yield should be studied further.