Soil tillage and machinery traffic influence soil water availability and air fluxes in sugarcane fields

Intensive soil disturbance by conventional tillage and heavy machinery traffic for planting, cultivation, and harvesting operations are the main causes of soil compaction and degradation of soil physical quality in sugarcane fields. However, the adoption of conservation soil tillage practices, such as no-till and reduced tillage associated with traffic control have been proposed as a key strategy to preserve soil physical quality, enhancing water availability and air fluxes. Nevertheless, the effects of reduced tillage associated with traffic control in sugarcane fields are still not well documented. A study was carried out to quantify soil water availability and air flux indicators in two soils with contrasting textures (named Sandy Loam and Clayey soil) under conventional and reduced tillage practices associated with and without controlled machinery traffic in central-southern Brazil. Soil physical parameters such as bulk density, total porosity, air-filled porosity, air permeability, pore continuity index, and the least limiting water range (LLWR) were measured. In both soils, there was no difference between conventional and reduced tillage in bulk density, air permeability, and LLWR. However, reduced tillage with non-traffic decreased bulk density and increased macroporosity, air-filled porosity, air permeability, pore continuity, and LLWR in Sandy Loam soil. In Clayey soil, the bulk density and LLWR did not change between tillage practices, but air permeability and pore continuity index were larger under reduced tillage with non-traffic. These results highlighted that soil disturbance by conventional tillage does not improve the water availability and air permeability during the crop cycle. However, the traffic control is essential to support the adoption of reduced tillage in sugarcane fields, preserving soil water availability and air fluxes for the subsequent ratoons. Reduced tillage and traffic control are two of the most important pillars for reducing soil compaction and promoting sustainability of sugarcane production in Brazil.