ABSTRACT Coastal Tablelands are flattened areas cut by valleys, which have predominantly Argissolos Amarelos (Yellow Argisol) and Latossolos Amarelos (Yellow Latosol). In contrast to this landscape, there are depressed circular areas, known as ponds, that create new dynamics in soil formation, due to the intermittent presence of water throughout the year. The soils of these pond areas are little known, which leads to the possibility of inappropriate use and management. The objective of this study was to describe the soils […]

ABSTRACT The sustainability of conservation farming systems is closely linked to return of nutrients to the soil through decomposition of crop residues. The aim of this study was to evaluate decomposition of crop residues and nutrient mineralization in soils with different textures over a 175-day incubation period. The experimental design consisted of a 6 × 4 × 5 factorial arrangement – six treatments, composed of four crop residues (corn, brachiaria, common bean, and Stylosanthes) and two controls, both without residues, […]

ABSTRACT Exchangeable Al is normally quantified in the extract of 1.0 mol L-1 KCl, but Al does not always come solely from exchangeable forms of the element. The objective of this study was to quantify Al forms existing in acid soils in order to elucidate if all Al-KCl comes from exchangeable forms. Soils samples with different mineralogical compositions were collected from many regions of Brazil. The following Al extractants were evaluated: the traditional method (1.0 mol L-1 KCl) and some […]

ABSTRACT Rubber tree (Hevea brasiliensis) crop may accumulate significant amounts of carbon either in biomass or in the soil. However, a comprehensive understanding of the potential of the C stock among different rubber tree clones is still distant, since clones are typically developed to exhibit other traits, such as better yield and disease tolerance. Thus, the aim of this study was to address differences among different areas planted to rubber clones. We hypothesized that different rubber tree clones, developed to […]

ABSTRACT Intrinsic equilibrium constants of 17 representative Brazilian Oxisols were estimated from potentiometric titration measuring the adsorption of H+ and OH− on amphoteric surfaces in suspensions of varying ionic strength. Equilibrium constants were fitted to two surface complexation models: diffuse layer and constant capacitance. The former was fitted by calculating total site concentration from curve fitting estimates and pH-extrapolation of the intrinsic equilibrium constants to the PZNPC (hand calculation), considering one and two reactive sites, and by the FITEQL software. […]

ABSTRACT Greater nitrogen (N) cycling is sought through Integrated Crop-Livestock Systems (ICLS). The aim of this study was to evaluate the effect of early fertilization of nitrogen applied to ryegrass grazed by sheep on the nitrogen nutrition index (NNI) of summer crops in ICLS. This study was carried out in a long-term protocol managed in the winter under two stocking methods, continuous and rotational, and two grazing intensities, moderate and low, with four replications. In summer, the area was divided […]

ABSTRACT Regosols in the Agreste Meridional region of Pernambuco, Brazil, are used for various agricultural activities, and prominent among them is production of common bean. An expressive variation is perceived in common bean crop yield, possibly associated with the presence of lamellae, which make for distinct water fluxes among these soils. The objective was to analyze the macro- and micromorphological, and physical characteristics of the Regosols located in the Agreste Meridional region of Pernambuco to understand the water fluxes in […]

ABSTRACT The impact of intensive management practices on the sustainability of forest production depends on maintenance of soil fertility. The contribution of forest residues and nutrient cycling in this process is critical. A 16-year-old stand of Pinus taeda in a Cambissolo Húmico Alumínico léptico (Humic Endo-lithic Dystrudept) in the south of Brazil was studied. A total of 10 trees were sampled distributed in five diameter classes according to diameter at breast height. The biomass of the needles, twigs, bark, wood, […]

ABSTRACT Preservation of mangroves, a very significant ecosystem from a social, economic, and environmental viewpoint, requires knowledge on soil composition, genesis, morphology, and classification. These aspects are of paramount importance to understand the dynamics of sustainability and preservation of this natural resource. In this study mangrove soils in the Subaé river basin were described and classified and inorganic waste concentrations evaluated. Seven pedons of mangrove soil were chosen, five under fluvial influence and two under marine influence and analyzed for […]

ABSTRACT The combined incorporation of sewage sludge (SS) and oat straw (OS) to the soil can increase straw carbon mineralization and microbial nitrogen immobilization. This hypothesis was tested in two laboratory experiments, in which SS was incorporated in the soil with and without OS. One treatment in which only straw was incorporated and a control with only soil were also evaluated. The release of CO2 and mineral N in the soil after organic material incorporation was evaluated for 110 days. […]