Abstract

The estimation of the amount of available water for plants through water retention curve under laboratory conditions is impeded by the high spatial and temporal variability of hydraulic properties of soils derived from volcanic ashes. The aim of this study was to estimate the water retention curve through pedotransfer functions (FPTS) in a soil derived from volcanic ash under a blueberry crop. The disturbed and undisturbed samples were taken from 5, 20 and 50 cm depth from an Acrudoxic Hapludand. The water retention curve was measured and then adjusted to the equation proposed by van Genuchten (1980). Besides, the organic matter, texture, bulk density, field capacity and permanent wilting point, were used in pedotransfer functions to estimate the air capacity and the plant available water using the Rosetta program. Although the van Genuchten model did not provide a perfect estimation of the bimodal nature of the water retention curve of the Andisol, the pedotransfer functions performed a good estimation of the plant available water. The FPT that showed the best estimation of the water retention curve was that based on both soil texture and bulk density