Mapping of soil chemical attributes in pasture areas in the Cerrado of Piauí, Brazil

Abstract

The low natural fertility and compaction of agricultural soils in the Cerrado are the main limitations for agricultural production. Changes in management systems are necessary to optimize the use of natural resources. The objective of this study was to map and evaluate the presence of penetration resistance and its relationship with soil chemical attributes in pasture areas in the Cerrado of Piauí. The experiment was carried out in the municipality of Corrente-PI, Brazil. The area was divided into two sub-areas of 0.5 ha each: the first is remaining vegetation and the second is pasture. Fifty soil samples were collected in the 0.00-0.20 and 0.20-0.40 m layers, with a sampling grid of 10 x 10 m. The pH in water, organic matter, calcium, magnesium, and soil penetration resistance were analyzed. The introduction of animals in the pasture area increased soil compaction by 2%. Chemical attributes, pH, organic matter, calcium and magnesium vary according to soil compaction by 2%. The native forest area has soil penetration resistance at acceptable levels (<2 MPa) and availability of nutrients at adequate levels. The maps of variability of organic matter, calcium, magnesium and penetration resistance showed the heterogeneity of the areas, allowing decisions based on specific management zones, localized application of nutrients and decompaction, and recovery of areas with inefficient management.