Uso do protocolo SMAF no estudo da saúde do solo em sistemas de uso e manejo no estado do Paraná

Abstract

Healthy soil is key to increasing food production sustainably. Evaluating the capacity of the soil to function is the focus of research in soil science, making an interaction of physical, chemical, and biological indicators and their integration into a comprehensive approach to soil health. A tool that has been used to interpret and integrate indicators is the Soil Management Assessment Framework (SMAF). The objective was to verify if the SMAF is sensitive to evaluate the health of Oxisols in different uses and managements in the state of Paraná, Brazil. The sensitivity of the scores obtained by the SMAF algorithms was evaluated using nine soil health indicators: bulk density, macroaggregate stability, water-filled pore space, pH, phosphorus, potassium, soil organic carbon, microbial biomass carbon and the β-glucosidase activity. These indicators were evaluated in different land uses and managements in eight sites in the state of Paraná. At the sites there is an area under no-tillage, secondary forest and a third use. This third use was different between sites (pasture, minimum tillage, conventional tillage, area with higher machine traffic in no-tillage and time of adoption of no-tillage). The surface layer of the soil was evaluated (0-0.10 m). Differences were observed for most soil health indicators used by the SMAF tool, but not all scores obtained showed differences. It is suggested that improvements should be made to the interpretation of macroaggregate stability and soil organic carbon. Despite the secondary forest being considered a reference in soil health, soil health indices in this environment in some sites were lower than in agricultural areas. Soil under no-tillage has capacity to perform its functions between 80% and 93% in near surface, and the soil under secondary forest showed a capacity to perform its functions between 75% and 91%. Soil health under no-tillage was similar to minimum tillage and conventional tillage. In pasture areas, soil health indices were similar or superior to no-tillage, and agroforestry systems seem to be promising in improving soil health. We conclude that the SMAF can be useful in soil health assessments in the state of Paraná, but that efforts must be made to improve the interpretation of some indicators.