This paper presents a parameterisation and test of an algorithm to calculate distributions of the major nutrient cations between the solution and exchangeable phases of soil when cation exchange capacity (c) may vary. Two contrasting soils were considered: a volcanic subsoil where c is dominated by variable-charge surfaces, and an alluvial silt loam topsoil with stable c. Experimental treatments consisted of applying either water or solutions of CaCl2, KCl, MgCl2, or NaCl. Solution concentrations of Ca2+, K+, Mg2+, and Na+ varied by up to two orders of magnitude, and were simulated well, particularly when using log10-transformed data. The ratios of the solution concentrations of K+, Mg2+, and Na+ to Ca2+ also were generally simulated well. However, the algorithm’s description of soil acidity needs further checking. For the variable-charge soil, cation concentrations were strongly influenced by fitted parameters associated with anion exchange. For the alluvial soil, fitted parameters had little influence, and the cation calculations were dominated by information gathered from the initial (equilibrium) distributions between phases. The algorithm has strong potential for forecasting changes in solution concentrations of the major nutrient cations, using relatively small amounts of fitting data.

中文翻译：

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一种计算土壤溶液阳离子组成的算法。2. 参数化和测试

本文介绍了一种算法的参数化和测试，用于计算当阳离子交换容量 (c) 可能变化时土壤的溶液相和可交换相之间的主要养分阳离子的分布。考虑了两种不同的土壤：火山底土，其中 c 由可变电荷表面控制，以及冲积粉砂壤土表层土，具有稳定的 c。实验处理包括应用水或 CaCl2、KCl、MgCl2 或 NaCl 溶液。Ca2+、K+、Mg2+ 和 Na+ 的溶液浓度变化高达两个数量级，并且得到了很好的模拟，尤其是在使用 log10 转换数据时。溶液中 K+、Mg2+ 和 Na+ 与 Ca2+ 的浓度比也得到了很好的模拟。但是，该算法对土壤酸度的描述需要进一步验证。对于可变电荷土壤，阳离子浓度受到与阴离子交换相关的拟合参数的强烈影响。对于冲积土，拟合参数几乎没有影响，阳离子计算主要由相间初始（平衡）分布收集的信息决定。该算法在使用相对少量的拟合数据预测主要营养阳离子溶液浓度变化方面具有很强的潜力。