运用四苯硼钠法准确测定土壤有效钾素变化的初步探讨

Accurate Quantification of Variation of Available K in Soil with NaBPh_4 Extraction Method

通过室内实验探讨了四苯硼钠法用来测定土壤有效K素变化的效果及其提取条件。结果表明,四苯硼钠法提取的土壤K量因四苯硼钠浓度、提取时间以及提取温度而有显著的变化。选择较高的四苯硼钠浓度、较长的提取时间或较高的提取温度均会显著促进四苯硼钠对土壤中非交换性K的提取。研究初步提出的一种土壤有效K素变化的测定方法,从12种土壤中提取的K量分别为各土壤常规缓效K值的2.3～7.4倍。当土壤添加100～2500mg/kg的外源K后,12种土壤中用该法测定的K素变化的回收率绝大多数在90%～110%之间,平均为101.9%±8.2%,说明改进后的四苯硼钠法将可以用来测定土壤中的有效K素变化。

The possibility of using NaBPh4 for accurate quantification of variation of available K in soil was discussed, Results of the laboratory test on 12 soils showed that soil K extraction with NaBPh4 was significantly influenced by the concentration of NaBPh4 used, duration, and temperature of the extraction, Higher concentration of NaBPh4, longer duration or higher temperature resulted in higher amount of soil K extracted by NaBPh4. A modified NaBPh4 extraction method was proposed for determination of variation of K in soil, With the modified method, the amount of K extracted with NaBPh4 was 2.3 to 7,4 times as high as that extracted with 1 mol/L boiling HNO3, When 100 to 2500 mg/kg K was added, the recovery rate of added K varied from 90% to 110%, and averaged at 101.9% ± 8.2%, suggesting that the modified method could be used for determination of variation of available K in the soils.