ABSTRACT The 1 M ammonium acetate (NH4OAc) (AA) is the most widely used method for soil-test potassium (K), but other methods have been also suggested to estimate crop available K. The accuracy of these extractants may be influenced by soil texture and clay mineralogy. This study evaluated the relationships among AA, Mehlich-3 (M3), and sodium tetraphenylboron (TPhB) methods using soils differing in texture and clay minerals from the agricultural area of Uruguay. The M3 and AA extractable K concentrations were highly correlated (R2 > 0.97) across soils, although AA extracted slightly higher amount of K than M3. The TPhB method extracted more K than AA and M3, indicating that extracted K from different pools. The slopes of the relationships between TPhB and AA or M3 varied among soils being higher in fine-textured and illitic soils than in coarse soils. These results would be useful for evaluating the feasibility of incorporating M3 into a test program using the existing calibrations of the AA method. In addition, TPhB could be considered a complementary tool to improve the interpretations of the extractants to estimate soil-test K along with other characteristics such as the texture and clay mineralogy.

中文翻译：

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醋酸铵、Mehlich 3 和四苯基硼钠作为萃取剂的比较以评估作物有效钾

摘要 1 M 醋酸铵 (NH4OAc) (AA) 是土壤测试钾 (K) 使用最广泛的方法，但也有人建议使用其他方法来估计作物有效钾。这些提取剂的准确性可能受土壤影响质地和粘土矿物学。本研究使用来自乌拉圭农业区的质地和粘土矿物不同的土壤，评估了 AA、Mehlich-3 (M3) 和四苯基硼钠 (TPhB) 方法之间的关系。M3 和 AA 可提取的 K 浓度在土壤中高度相关（R2 > 0.97），尽管 AA 提取的 K 量略高于 M3。TPhB 方法提取的 K 比 AA 和 M3 多，表明从不同的池中提取 K。TPhB 与 AA 或 M3 之间关系的斜率因土壤而异，细粒土和伊利石土高于粗土。这些结果将有助于评估使用 AA 方法的现有校准将 M3 纳入测试程序的可行性。此外，TPhB 可以被视为一种补充工具，以改进提取剂的解释，以估计土壤测试 K 以及其他特征，如质地和粘土矿物学。