Procedimento experimental combinando infiltrômetros de anel simples e de aspersão: interpretação hidrodinâmica em solos sob agroecossistemas do Sertão do Pajeú

Abstract

The knowledge of the hydrodynamic properties of the soil is of fundamental importance for the simulation of hydrological processes, contributing to the resolution of problems associated with the conservation of the environment, agriculture, and water resources. The removal of the natural vegetation of the Caatinga, linked to the extended periods of drought, results in a scenario of degradation of the semi-arid soils. Agroforestry systems (SAFs) emerge as alternatives to minimize soil degradation in this region. In this context, it is essential to understand the functioning of different soil management systems during periods of water limitation in order to analyze their recovery capacity. In this way, we propose to evaluate the influence of three types of soil cover (pasture, Caatinga, and agroforestry) on a set of hydrodynamic parameters inherent to water infiltration in soils, such as hydraulic conductivity (Ks) and sorptivity (S), and others that help in the description of retention curves θ(h) and hydraulic conductivity K(θ), essential to the analysis of physical quality and understanding of water dynamics in these soils. Experiments with a single ring and sprinkler infiltrometers made it possible to interpret the values of Ks and S. The semi-physical method called Beerkan, based on infiltration measurements and soil particle size distribution, makes it possible to characterize the parameters that describe the θ(h) and K(θ) curves, according to the van Genuchten and Brooks & Corey models, respectively. Most of the results expressed differences in the physical-hydric quality of the soils, with greater emphasis on the areas of Caatinga and the agroforestry system. The agroforestry system proved to be resilient, showing potential for recovering degraded areas in a short time.