Potential of Amazonian Dark Earth for agricultural use in the Middle Urubu River, Itacoatiara, Amazonas

Abstract

In the Brazilian Amazon, the Urubu River is a typical blackwater river in Amazonas where anthropic soils are frequently found along its banks, where family units also reside and basically survive from the agricultural use of these areas. The aim of this research was to analyze morphological, physical, and chemical attributes, as well as the forms of use, of an Amazonian Dark Earth (ADE) located on the left bank of the middle Urubu River in Itacoatiara, Amazonas. Geographic information was collected for the construction of land use maps, as well as soil samples, which were analyzed for color and for physical and chemical attributes. The results showed small variations in the color of the ADE with depth, with a predominance of very dark brown color. The textural composition was silty loam, while in the adjacent soil, yellower colors and clay content above 50% predominated. In the ADE, chemical analysis indicated higher levels of organic matter and nutrients, especially calcium (Ca) and phosphorus (P), compared to the adjacent soil. The changes promoted by human activity in the Amazon resulted in anthropic soils with a higher amount of macronutrients when compared to non-anthropic soils.