The economic development of Brazil is governed by the increasing agricultural production, associated with the conservative practices. The no-tillage system (NT) is the soil management practices that bring together the broadest set of precepts for conservation agriculture. Areas under NT, however, have shown two completely different soils layers: a surface, around 0-0.07 m, with physical and chemical conditions favorable for root development; and a sub-surface layer, around 0.07-0.20 m, with lower permeability, high penetration resistance and low soil fertility. These conditions restrict the root growth to the surface layer, reducing plant productivity by water deficit. This problem extends over 30 million hectares of cultivated areas under NT in Brazil, endangering the agricultural exuberant projections in the country. Therefore, this requires research activities. This project aims to study the factors that promote soil physical and chemical stratification in NT cultivated areas. Among the factors that may cause soil degradation will be evaluated: (i) excessive surface limestone application, increasing the soil pH beyond the PCZ and the electronegative potential, causing clay dispersion in the surface layer; (ii) insufficient biomass supply and acceleration of mineralization by biological activation, caused by liming and fertilization, may decrease the aggregate stability promoting clay eluviation; and (iii) over-application of fertilizer with high salt content, which may favor the clay dispersion with subsequent migration of these to the subsurface layer. A better understanding of these factors will help define strategies to improve the NT in the country and, thus, enable increased agricultural production coupled with conservatism.
News published in Agência FAPESP Newsletter about the scholarship: