Highly weathered tropical soils have low P plant availability and very high inorganic phosphorus (Pi) adsorption capacity. Therefore, maintenance of organic sources able to supply P by mineralization is essential for P availability under highly weathered conditions. Organic matter cycling and tolerance to low P soil concentration of the plant community may guarantee sustainability in natural ecosystems. The aim of this study was to evaluate organic phosphorus (Po) content and labile P fractions in the soils of three sites. The […]

Liming is a common practice to raise soil pH and increase phosphorus (P) bioavailability in tropical regions. However, reports on the effect of liming on P sorption and bioavailability are controversial. The process of phosphorus desorption is more important than P sorption for defining P bioavailability. However few studies on the relationship between soil pH and P desorption are available, and even fewer in the tropical soils. The effects of soil pH on P sorption and desorption in an Ultisol […]

The aim of this work was to evaluate the nutrient input through litterfall, in one area degraded by soil remotion, replanted with ten-year-old nitrogen-fixing legume trees Acacia auriculiformis (acácia), Gliricidia sepium (gliricídia), and Mimosa caesalpiniifolia (sabiá) and another neighbor area with a secondary growth Atlantic forest (“capoeira”) fragment. The experiment was carried out at the Embrapa – Agrobiologia research station, Km 47, Seropédica, State of Rio de Janeiro, Brazil. The litterfall was quantified in litter traps with an area of 0.25 m2; […]

This study analyzes homogenous stands of Eucalyptus grandis and Pinus caribaea var. hondurensis in different growth stages as well as fragments of natural vegetation of “Cerrado” and Atlantic Forest. The climatic, edaphic and floristic conditions of the chosen areas are representative of the native forests and forest plantations established at the Western plateau of the state of São Paulo. Soil samples (0-15 cm) were incubated under aerobic and anaerobic laboratory conditions by successive periods of 3, 3, 4, 4, 6 […]