Encouraged by the state's rural extension service, many farmers now keep their fields covered with living or dead biomass during the fallow and planting seasons, in order to protect the soil from the direct impact of rain drops, excessive sunshine and wind. The adoption of cover crops has been accompanied by the emergence of minimum tillage, which limits to a narrow strip of 10-50 cm the area of soil that is disturbed in land preparation. The advantage of these practices includes reduction in soil losses, labour requirements and production costs, and more flexibility in the timing of sowing. Direct sowing must be considered as a system, and not merely as a method of land preparation. For the system to be successful, it is necessary to introduce crop rotation, i.e. the use in time and space of a sequence of species.
Crop rotation is the basis for the sustainability of direct-sowing systems.