Propiedades físicas y conductividad hidráulica efectiva en el transcurso de una rotación trigo/soja

Abstract

Agricultural farming generate changes in the soil physical properties, which are not normally considered in runoff and erosion models. The objectives of this work are: 1) Determine temporal changes of various surface soil physical properties in a vertic Argiudoll under no tillage, in three stages corresponding to a wheat /soybean rotation. 2) Estimate the matric suction at the wetting front (Ψ) in two different ways and calibrate the effective hydraulic conductivity of the Green-Ampt infiltration model (Ke) by two different methods from field infiltration tests, determining most appropriate estimation methods for such parameters. 3) Using a runoff model, determine if the Ke calibrated in small plots changes through scales. Different soil physical properties were determined and rain simulation tests were performed in three moments of a wheat/soybean rotation. The study was performed in a field of the Faculty of Agronomy, National University of Rosario (Sta. Fe, Argentina). Ke was calibrated by two procedures and Ψ in two ways was also estimated. There were no significant differences in the various properties analyzed between the three stages of the trial. The Ψ estimate was more efficient from the equation that considers only soil texture and porosity. The Green-Ampt infiltration model was more effective to calibrate Ke, compared to that which calculate time to ponding. The properties derived from infiltration process had more spatial variability than temporal heterogeneity. Ke calibrated at small plots was higher by 66 to 100% compared to a greater area.