The importance of an alternative for sustainability of agriculture around the periphery of the Amazon rainforest.

The unsustainable use of the soil of the deforested area at the Amazonian border is one of the greatest threats to the rainforest, because it is the predominant cause of shifting cultivation in the region. The sustainable management of soils with low natural fertility is a major challenge for smallholder agriculture in the humid tropics. In the periphery of Brazilian Amazonia, agricultural practices that are recommended for the Brazilian savannah, such as saturating soils with soluble nutrients do not ensure the sustainability of agroecosystems. Improvements in the tilled topsoil cannot be maintained if deterioration of the porous soil structure is not prevented and nutrient losses in the root zone are not curtailed. The information gleaned from experiments affirms that in the management of humid tropical agrosystems, the processes resulting from the interaction between climatic factors and indicators of soil quality must be taken into consideration. It must be remembered that these interactions manifest themselves in ways that cannot be predicted from the paradigm established in the other region like the southeast of Brazil, which is based only on improving the chemical indicators of soil quality. The physical indicators play important role in the sustainable management of the agrosystems of the region and for these reasons must be considered. Therefore, alley cropping is a potential substitute for slash and burn agriculture in the humid tropics with both environmental and agronomic advantages, due to its ability to produce a large amount of residues on the soil surface and its effect on the increase of economic crop productivity in the long term. The article presents some promising patents on the importance of an alternative for sustainability of agriculture.