Sorption of phosphate by soils is an important determinant of fertiliser efficiency. Its extent and rate differ between soils. This paper considers both how these differences can be described and how they can be explained. Published data on the rate of reaction of soil with phosphate are assembled. There are 88 soil samples from five continents, as reported in six publications. In almost all cases, sorption (S) was related to solution concentration (c) and time (t) by: S = a c^b1t^b2 – qt^b3. The term after the minus sign describes the rate of desorption; its value is affected by soil phosphate status. The “a” parameter reflects the amount of adsorbing surfaces present plus their affinity for phosphate. The b₁ parameter, which describes the curvature of the sorption plots, reflects the composition of the adsorbing surfaces and their phosphate status. Large values are obtained for soils with a small range of electric potentials of their reacting surfaces and a low phosphate status, as is common for Australian virgin surface soils. The greatest influence on the b₂ parameter, which describes the curvature of the plots against time, is the method of measurement. Large values were observed when soil and solution were shaken together and are probably an artefact caused by mutual abrasion of the soil particles. When this problem was avoided, large values of b₂ were associated with very phosphate‐deficient soils; small values of b₂ often occurred when b₁ was also small, suggesting surfaces of varying potential were present. If the substances present included components such as kaolin, that might explain both the range in potentials and limited penetration.

中文翻译：

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使用现有的观测资料描述和解释土壤与磷酸盐的反应

土壤对磷的吸附是肥料效率的重要决定因素。它的范围和速率因土壤而异。本文考虑了如何描述这些差异以及如何解释它们。汇总了有关土壤与磷酸盐反应速率的公开数据。据六份出版物报道，有来自五大洲的88个土壤样品。在几乎所有情况下，吸附量（S）与溶液浓度（c）和时间（t）的关系如下：S = ac ^{b 1} t ^{b 2} – qt ^{b 3}。负号后的术语表示解吸速率；其价值受土壤磷酸盐状况的影响。“ a ”参数反映存在的吸附表面的数量及其对磷酸盐的亲和力。在b ₁参数，其描述了吸附曲线的曲率，反映了吸附表面和它们的磷酸盐状态的组合物。对于其反应表面的电位范围较小且磷酸盐状态较低的土壤，可得到较大的值，这在澳大利亚原生表面土壤中很常见。对b ₂的最大影响测量方法是描述曲线随时间变化的曲率参数。当土壤和溶液一起摇动时，观察到较大的值，这可能是由于土壤颗粒相互磨损引起的假象。当避免这一问题时，大量的b ₂与磷酸盐含量极低的土壤有关。当b ₁也很小时，经常会出现b _2的较小值，这表明存在变化电位的表面。如果存在的物质包括高岭土等成分，则可能解释了电位范围和有限的渗透率。