Physical and chemical attributes of soil in ecosiste of Mombaça grass in the eastern Amazon

Abstract

Cattle raising is the production basis of the Amazon region, but the land intended for grazing is, in most cases, degraded or under degradation process due to a combination of factors: inadequate formation, inappropriate handling, low fertility of the local soil, high acidity, and high aluminum toxicity. The purpose of this research was to characterize the influence of forage formation time on the chemical and physical characteristics of Ultisol after the conversion of secondary forest into pasture of Panicum maximum cv. Mombasa grass with different formation ages. Soil samples collected at 0-7 cm and 7-15 cm depths under secondary forest and pastures with one, two and three years of formation were analyzed. The experiment was carried out at four (formation time) × two (depth) factorial arrangement with 20 replications. Among the soil chemical characteristics, only potassium was not affected by the depth and formation time of pastures; all soil physical properties were influenced by depth and in relation to changes in the systems of secondary forest and pastures with one, two and three years of formation. The conversion of forest into Mombasa grass pasture in the eastern Amazon has influenced most of the chemical and physical characteristics of the local soil. The chemical characteristics presented a slight improvement, followed by a decrease over the time of pasture area formation. The physical properties of the local soil were negatively affected by the increase of pastures handling time.