土壤速效氮测定方法的改进

摘要

From three aspects, sodium hydroxide concentration, distillation rate and adding agent or not, to optimize the method to measure soil available nitrogen of kay type nitrogen determination apparatus and compared precision with diffusion dish method currently used. The results showed that: in the case of 3.5 mol/L sodium hydroxide solution, 60% of the distillation efficiency, and not adding reductant, the results of two methods is similar, and closes to the value of soil reference materials. But the precision of the kjeldahl definition is higher. Therefore, it is feasible to measure soil available nitrogen by the kjeldahl nitrogen determination apparatus, and it is more convenient and quicker than diffusion method.%从氢氧化钠浓度、蒸馏速率和添加还原剂与否3个方面优化了凯式定氮仪测定土壤速效氮的方法,并与目前常用的扩散皿法进行精密度比较.结果表明:采用3.5 mol/L的氢氧化钠溶液、60%的蒸馏效率,在不添加还原剂的情况下,土壤速效氮的测定值与扩散皿法相差不大,均与土壤标准物质的标准值接近.但凯氏定氮仪测定土壤速效氮的精密度相对较高.因此,采用凯氏定氮仪测定土壤速效氮是切实可行的,并且比扩散皿法更方便、快捷.