Estimation of Water Available for Plants in Cuban Soils as a Function of Prevailing Texture

"The objective of this work is to determine the total soil water availability and easily usable reserve for plants as a function of predominant soil texture. That will be done from information existing for the most important Cuban soils. It will be used as a tool that facilitates efficient irrigation programming. Data were available from 131 soil subtypes and 11 soil groupings, according to the database of the Agricultural Engineering Research Institute (IAgric) of Cuba. The soil depth considered was 0.5 m and a predominant particle size value was assigned to each soil profile according to its texture. Values were adjusted with a logarithmic regression analysis of the gravimetric and volumetric soil water content corresponding to the point of field capacity (Cc) and permanent wilting point (PMP). The values of the Total Available Water in the Soil (ADP) and the Easily Usable Reserve (RFU) were also quantified. The obtained relationships allow predicting in more than 90%, the variation of the limits of these soil water reserves, based on the predominant particle size in its textural composition. The ranges of variation of these limits are higher than the ranges defined at international level for silt and clay, which is associated with the characteristics of the predominant clay in many Cuban soils. The results have a high practical value as a basis for the efficient programming of crop irrigation and allow reducing the hard field and laboratory work involved in these studies."