Chemical of Soils With Histic Horizon of Lakes and Riparian of the Savanna, Northern Amazonia, Brazil

The savanna of the northern Amazon of Brazil is an ecosystem that presents lakes and riparian of buriti (Mauritia flexuosa L.) in its landscape. Although these ecosystems are protected by law, they are subject to changes by anthropization in their surrounding areas. The soils of lakes and on the banks of the buriti riparian of the savanna of Boa Vista, Northern Amazonia, are hydromorphic and, although they are important ecosystems for the environmental sustainability, they are little studied. Thus, the purpose of this work was to characterize the chemical composition of these soils and relate the results to the type of anthropization. Samples were collected at the margins of five riparian and three lakes in the 0.0-0.1, 0.1-0.2, 0.2-0.3, 0.3-0.4, and 0.4-0.5 m depth layers. Soil samples, in each environment, were taken from three points equidistant at 100 m. For soil characterization, pH in water, H + Al, Al3+, P, K+, Mg2+, Ca2+, and total organic C (TOC) were determined. The soils of lakes and buriti riparian are of high acidity, low natural fertility, and high toxicity by Al. Buriti riparian presented the highest levels of TOC but were also the environments most susceptible to the effects of anthropization, in which Bom Intento presented values of available P from medium to high by the interference of agricultural activities.