The objective of this research was to evaluate the effect of the concentration of a hydrogel polymer on the water retention characteristics of a sandy clay loam and a clay soil. Water retention curves were obtained for the two soils and for a mixture of these soils with the Terracottem® at 0.01, 0.05, 0.10, 0.15 and 0.20 dag kg-1 concentrations. The evaluation of the changes in water retention characteristics was done considering the values of the total water availability (TWA), field capacity and the wilting point. For both soils, there was no effect of the hydrogel polymer concentration on the water retention when the matric potentials were less than -1.0 MPa. However, for matric potentials higher than -1.0 MPa, the water retention increased as the concentration of the hydrogel polymer in the mixture increased. The hydrogel polymer, at 0.20 dag kg-1 concentration, increased the water retention, at the 0.03 MPa matric potential, by 41% for the sandy clay loam and 37% for the clay soils, when compared to the soils without hydrogel polymer (control treatment) and increment in the available water retention made the TWA of the two soils to increase by 123 and 135%, respectively.
hydrogel polymer; soil conditioner; water retention
