Preconsolidation pressure, soil water retention characteristics, and texture of Latosols in the Brazilian Cerrado

Abstract

In the Brazilian Cerrado Biome, Latosols (Oxisols) predominate on gently sloping areas and are highly suitable for the development of mechanised agriculture. However, inappropriate management may lead to reduced crop yields and environmental degradation. We examined the relationships between compression behaviour and texture of Latosols to support decisions on the sustainable use and management of agricultural land. We collected soil samples in 10 Latosols with variable textures under native vegetation and determined the oxide content, bulk and particle density, total porosity, water retention curves, and preconsolidation pressure at different water potentials to develop preconsolidation pressure models. Our results showed that soil texture influenced soil physical properties, that is, an increase in the clay content enhanced the total porosity and water retention and decreased bulk density. Consequently, the susceptibility of these soils to compaction increased with an increase in the clay content. Considering the characteristics of the machinery used in intensive Brazilian agriculture, the compaction risk of these soils was considered high, despite the differences in resistance of the soils. In clayey and very clayey soils, some additional compaction is almost inevitable, even when the water content is low. Thus, caution is required in the evaluation of structural changes after mechanised field operations.