Potential land availability for agricultural expansion in the Brazilian Amazon

The Amazon hosts one of the largest stocks of arable land in the world. However, little is known about the available extent of agricultural land in conformity with legal, agronomical and environmental requirements. This study aims to identify and quantify potentially available areas for agricultural expansion in the Brazilian Amazon considering the extent of: (i) legally available forested lands, (ii) previously converted lands with suitable productive capacity and (iii) previously converted lands free of land use conflicts. This analysis was carried out by integrating georeferenced information on land use, soil fertility, terrain slope, biomass, protected areas and land use policies (e.g. Brazilian Forest Code) into a conditional decision support procedure, based on Boolean inference techniques. Our results showed that 11.69% (493,103.03 km2) of the Brazilian Amazon would be potentially available for agricultural expansion in the year 2010. This area was essentially dominated by forests (59.37%), followed by previously converted lands (40.63%). The extent of this area was equivalent to 75.86% of the total cultivated area in Brazil in 2010. However, the effective usage of these areas would have direct political and environmental implications. First, it is expected that the effective usage of available forests would detract recent achievements of the Brazilian Action Plan for Prevention and Control of Deforestation in the Amazon, which has reduced deforestation by 79% from historical rates. Moreover, the conversion of these areas could result in a committed emission of 13 ± 1 Pg CO2eq to the atmosphere which is equivalent to the total emissions from land cover change registered in Brazil during the 2000-2010 period. Therefore, the compensation of environmental liabilities stands as the most consistent destination for the available forests mapped in this study. To minimize environmental impacts, agricultural expansion in the Brazilian Amazon should be restricted to already converted areas. This land cover class totalizes 200,000 km2, which could support agricultural expansion without promoting the advance of deforestation.