Pedotransfer functions for water retention and hydraulic conductivity in soil under subsoiling

Abstract

This experiment aimed to develop pedotransfer functions, based on soil physical-hydric attributes, to estimate the water retention and hydraulic conductivity. The experiment was carried out in area with a Conilon (Coffea canephora Pierre) coffee crop irrigated and subjected to subsoiling in the row of planting. Undeformed samples were collected on the row (P1) and inter row (P2) of the crop from the layer 0 to 0.80 m, to determine the water retention curve in the soil, and soil conductivity by using Guelph permeameter. The pedotransfer functions showed underestimates for the potentials 0, -500 and -1500 kPa and -6, -10, -33 and -100 kPa, respectively in P1 and P2. In P2 the average relative error for the potential percentage was 8.42%, which is higher than the P1 (4.87%), resulting in higher error in the estimates of height of water stored in the soil. The water retention curve for the subsoiled soil may be estimated with error less than 5%, by clay, total porosity, macroporosity, microporosity and soil density attributes, and the hydraulic conductivity by soil clay fraction. For non-subsoiled soil, the retention curve may be estimated with error less than 9%, by the total pore volume and macro and micropores and the hydraulic conductivity by the coarse sand fraction.