Hierarquia integrada da qualidade físico-hidráulica do solo em uma bacia hidrográfica

Abstract

To assess soil physical quality and its implications for water use and management, an experimental grid was established in the Ellert creek watershed (ECW) located in Canguçu-RS, Brazil. Disturbed and undisturbed soil samples were collected at 169 sampling points, at a depth of 0-0.20 m, where the textural fractions (clay, silt, and sand) and the physical-hydraulic properties of soil density, total porosity, microporosity, macroporosity, saturated hydraulic conductivity, organic carbon content, and soil water retention curve (SWRC) were determined. The soil in the study area is predominantly classified as Orthents. Hydraulic energy indices related to soil aeration and water retention were calculated by integrating areas under the SWRC. By combining the absolute indices of aeration and retention with drainable porosity, plant-available water, sand and clay contents, and soil density, a single soil physical-hydraulic health index (BSPHHI) was developed. Higher BSPHHI values were found in soils cultivated with native forest and silviculture, while lower values were found in soils cultivated with annual crops. A hierarchical analysis of soil physical quality indices was also performed, ranging from basic metrics such as soil density and total porosity to more complex indices of hydraulic energy and matric flow. This hierarchical approach facilitated a comprehensive analysis of soil aeration, water retention, and flow processes, providing valuable insights for the rational management of soil and water in the watershed. The BSPHHI and the hierarchical analysis of soil physical quality can assist producers in making decisions about future soil and water conservation practices in the watershed.