Arya and Paris developed a model in 1981 to predict the water retention curve of a soil from the grain size distribution and the porosity. This model was very convenient due to the simplicity of the input parameters, and because experimental measures are expensive and with no lack of uncertainties. The model was based on very simple equations but the need to discretize the grain size distribution restricted its usability. A new model is presented, preserving the physical meaning but solving this dependency and other issues and allowing a continuous expression that was not possible with the original model. The new model is very convenient and practical as expressions are easy to implement, and its predictions depend on only one parameter for which some recommended values are also included. Limitations and uncertainties of the model are also discussed.

Arya 和 Paris 在 1981 年开发了一个模型，用于根据粒度分布和孔隙率预测土壤的保水曲线。由于输入参数的简单性，并且因为实验措施昂贵且不乏不确定性，该模型非常方便。该模型基于非常简单的方程，但离散粒度分布的需要限制了其可用性。提出了一个新模型，保留了物理意义，但解决了这种依赖性和其他问题，并允许原始模型无法实现的连续表达。新模型非常方便实用，因为表达式易于实现，其预测仅依赖于一个参数，其中还包含一些推荐值。