Pedotransfer functions for predicting water content in Oxisols and Ultisols from Brazil

Abstract

The objective of the study was to develop pedotransfer functions (PTF) to predict soil water content in the -33 (field capacity) and -1,500kPa (permanent wilting point) potentials and available water content, from granulometric data, bulk density, and organic carbon from soil profiles. The soil database used in the study comprised 682 horizons from Yellow Oxisols and Ultisols, developed from Barreiras Formation and similar sediments, from different Brazilian localities. The PTF were developed using the backward stepwise selection method. Evaluation prediction efficiency of each pedofunction was obtained on the basis of determination coefficient (R²), the estimate standard error (ESE) and graphic interpretation. The developed equations presented good determination coefficients, indicating that they could be used for prediction of water content at the –33 and -1,500kPa potentials in Oxisols and Ultisols. Water availability variable shows high percentage of factors not explained by the equation variables. The PTF for the water availability variable underestimates the values higher than 0.10 kg kg^-1.