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酸性土壤交换性金属阳离子总量的测定,杰克逊推荐用平衡pH法,即用1N醋酸置换法来测定土壤的交换性金属阳离子总量,小心测出所引起的pH变化对照醋酸的pH标准滴定曲线,从而求出溶液中H~+的减少数量。这个方法需要极精密的酸度测定,要求pH准确到0.01—0.02 pH单位,这点对于一般的实验室来讲,是比较不容易做到的。本文在条件试验的基础上拟订的溴酚蓝光度法测定,克服了这一困难。实验结果表明,样品回收率在98.3—103％之间相对标准偏差在1.4％以内,方法的准确度和精密度良好。
Determination of the total amount of exchangeable metal cations in acidic soils, Jackson recommends the equilibrium pH method, which uses 1 N acetic acid displacement method to determine the total amount of exchangeable metal cations in the soil, and carefully measures the resulting change in pH. The standard acetic acid pH titration curve , To find the solution to reduce the number of H ~ +. This method requires extremely accurate acidity determination, requiring pH to be accurate to 0.01-0.02 pH units, which is less easy for a typical lab. This article overcomes this difficulty by the bromophenol blue photometric method developed on the basis of the condition test. The experimental results show that the relative standard deviation of sample recovery within 98.3-103% is within 1.4%, and the accuracy and precision of the method are good.