An alternative continuous form of Arya and Paris model to predict the soil water retention curve of a soil

•A new model, ACAP, has been developed, based based on Arya and Paris, 1981, but overcoming some previous detected problems.•A simple physic-empirical continuous expression is reached to estimate the water retention curve of a soil.•The resulting expression use of one only parameter β, for a selected scaling parameter D0.•The inputs for the new expression are basic soil properties: the grain size distribution and porosity.