Sistema de avaliação da aptidão agrícola das terras aplicado a solos da planície do rio Madeira, sul do Amazonas

Abstract

Amazonian soils exhibit remarkable pedological diversity and play a fundamental role in ecosystem functioning and agricultural production. However, the intense action of weathering and leaching processes results in high soil acidity, low natural fertility, and chemical constraints that limit their land-use potential. In this context, Land Agricultural Suitability Assessment constitutes an important tool for land-use planning and the development of management strategies compatible with environmental conditions. This study aimed to evaluate the agricultural suitability of soils from the Madeira River Plain, southern Amazonas State, Brazil, using the Land Agricultural Suitability Assessment System (SAAAT) to support sustainable land use. Four representative soil profiles were evaluated and classified according to the Brazilian Soil Classification System (SiBCS) using morphological, physical, and chemical attributes obtained from a database compiled from previous studies conducted in the study area. Agricultural suitability was assessed following the methodology proposed by Ramalho Filho and Beek (1995), considering the main land-use limiting factors under different management levels, and the data were subjected to descriptive statistical analysis using the R software environment. The results revealed a predominance of strongly acidic soils with low base saturation, high aluminum saturation, and low nutrient availability, confirming their inherently low natural fertility. Particle-size analysis showed the predominance of the silt fraction and an increase in clay content in subsurface horizons, indicating the occurrence of argilluviation processes. The Latossolo Vermelho-Amarelo Alumínico típico exhibited the highest relative agricultural potential, whereas the Plintossolo Argilúvico Alumínico típico presented the greatest limitations for intensive agricultural use. It is concluded that the SAAAT is an effective tool for identifying the agricultural limitations and potential of Amazonian soils, supporting land-use planning, agro-environmental zoning, and the development of management strategies aimed at the sustainable use of land.