Abstract

PAZ, A. M.; CIPRIANO, D.; GONCALVES, M. C.  and  PEREIRA, L. S.. Pedotransfer functions for the soil water retention curve. Rev. de Ciências Agrárias [online]. 2009, vol.32, n.1, pp.337-343. ISSN 0871-018X.

Pedotransfer functions allow prediction of the soil hydraulic characteristics from basic soil data. In this study pedotransfer functions were developed in order to obtain three specific points of the soil water retention curve: field capacity, wilting point and maximum capacity, which were considered to be correspondent to the water held in soil against suctions of 0.25 kPa, 9.8 kPa and 1554 kPa. The basic properties of soil used were particle size distribution, organic content, bulk density, depth of the layer and the statistical variables geometric mean diameter and geometric standard deviation of the soil particles. The method for building the functions was multiple linear regression analysis with 304 measurements of soil layers from numerous soil families from different locals in Portugal. The adjusted coefficient of determination of the pedotransfer functions was higher than 0.84. The validation of pedotranfer functions was made with a regional, independent data set of 55 measurements, obtained in this study for a particular irrigation area in Alentejo. The correlation coefficient obtained between the values predicted with the pedotransfer functions and the measured ones, for water retained in the soil at 0.25 kPa, 9.8 kPa e 1554 kPa was, respectively, 0.90, 0.73 and 0.85 which were considered significant at the 0.1% probability level.

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