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本文描述了一种常规测定土壤全N的简便方法。该法的步骤包括:(1)将土样置于硬质玻璃(pyrex)消煮管中,加入酸性重铬酸钾溶液,在预热至170℃的40管组合消煮器上消煮45分钟;(2)滴定加碱(NaOH)蒸馏消煮液释放出的NH_3-N;(3)将测定的NH_3-N值乘上校正系数计算出土壤全N量,用本方法对全N含量范围较宽而其它性质各异的14种土壤进行分析的结果表明,未校正的N回收率在88.5-92.3%之间,平均为90.5%,当将结果乘上校正系数1.1时,N回收率在97.4-101.5%之间,平均为99.6%。本方法快速精确,每个工作日可分析80个样品,仅需用凯氏法分析土壤全N的一股设备(40管组合消煮器和蒸汽蒸馏装置),用于消煮土样的酸性重铬酸钾溶液是Mebiu(?)改良法测定土壤有机碳的常用试剂,本法除了比凯氏法简便快速外,还无需使用凯氏法消煮过程中所需的花费较大的烟雾处理系统。
This article describes a convenient method for routine determination of total N in soil. The steps of the method include: (1) placing the soil sample in a pyrex digestion tube, adding an acidic potassium dichromate solution, digesting 45 in a 40-tube combined digester preheated to 170 ° C Min; (2) NH3-N released from the titration and base (NaOH) distillation retort liquor; (3) multiplying the measured NH3-N value by the correction coefficient to calculate the total N content of the soil; A wide range of other 14 different soil properties were analyzed and the results showed that the uncorrected N recovery was between 88.5-92.3% with an average of 90.5%. When the result was multiplied by a correction factor of 1.1, the N recovery Between 97.4 and 101.5%, an average of 99.6%. The method is fast and accurate. Each working day can analyze 80 samples. Only one Kjeldahl analysis device for soil N (40-tube combination digester and steam distillation unit) is used to analyze the acidity Potassium dichromate solution is Mebiu (?) Improved method for the determination of soil organic carbon common reagents, this method in addition to Kjeldahl simple and quick method, but also without Kjeldahl elimination process required spent more smoke treatment system.