The use of animal manure in agricultural systems can cause water contamination and/or pollution by nutrients, especially by consecutive applications to the same area. In view thereof, the purpose of this study was to evaluate the effect of manure and fertilizer application on NH4+, NO3–, P and K leaching. For this evaluation, undisturbed soil columns were collected from a seven-year field experiment that consisted of 12 treatments, resulting from the combinations of four doses of dairy slurry with three doses […]

The determination of As by hydride generation atomic absorption spectroscopy (HG-AAS) is a simple, sensitive, precise and low-cost method. However, this technique requires the pre-reduction of the existing As(V) species, which is obtained by the use of reducing agents such as KI. In extracts containing oxidizing agents, the pre-reduction of As is impaired, as it occurs in extracts obtained by the BCR (French acronym for Community Bureau of Reference) method for the sequential extraction of As in sediments. The objective […]

The ability of a soil to keep its structure under the erosive action of water is usually high in natural conditions and decreases under frequent and intensive cultivation. The effect of five tillage systems (NT = no-till; CP = chisel plowing and one secondary disking; CT = primary and two secondary distings; CTb = CT with crop residue burning; and CTr = CT with removal of crop residues from the field), combined with five nutrient sources (C = control, no […]

Exchangeable Al has been used as a criterion for the calculation of lime requirement in several Brazilian States. However, the laboratory method with extraction by a 1 mol L-1 KCl solution followed by indirect alkaline titration is not accurate for some Brazilian soils, mainly in the case of soils with high organic matter content. The objective of this study was therefore to evaluate the stoichiometry of H+/Al3+ in KCl soil extracts. The results suggested that organically complexed Al is the […]

With the development of agriculture, the use of new tools for the evaluation of the properties related to plant yields have become essential to improve the management of agricultural systems. The purpose of this study was to use a fuzzy model to investigate, based on soil chemical properties, the propagation of uncertainty of the acidity of a humic Red-Yellow Latosol (Oxisol) under Arabic coffee plantation. The soil was sampled at a depth of 0 – 0.2 m, in a grid, […]

Many studies have shown the importance of the soil microbial biomass, mainly as source/sink of carbon (C) and nitrogen (N) in forest stands. However, there are few studies focused on microbial P (MPH), especially in relation to the determination methods of MPH in these ecosystems. For an evaluation of the methods used to determine microbial P (MPH) in soils, three methods were evaluated: fumigation-extraction (FE); radiation with microwave-extraction (RE); and radiation by microwave-extraction with a membrane for anionic exchange (EMAE). […]

The agricultural activity can change the quantity and quality of soil organic matter (SOM), resulting in CO2 and N2O emissions from the soil. No-tillage (NT) with legume species in crop rotation is a strategy that should be considered not only to increase the SOM quantity, but also to reduce greenhouse gas emissions. The objective of this study was to determine the soil-atmosphere gas emissions with greenhouse effect (CO2 and N2O). For this purpose, an experiment was installed in Tibagi (Paraná […]

The pedogenesis of Planosolic soils, especially of the semi-arid “Agreste” region of Pernambuco State, Brazil, has n ot been properly studied. There are indications and doubts with regard to some aspects such as possible duality or differentiated reworked parent material, total of gains and losses and the relative mobility of the main constituent elements during soil evolution. Three soils with strong texture contrast were studied in a toposequence of the region. Three soils with a strong textural contrast on a […]

Si made available by Ca silicate can increase polyphenol formation, which could increase the persistence of crop residues on the soil surface. The present study evaluated the effect of silicate and lime on decomposition of different crop residues and the nutrient release for the development of common bean plants. An experimental design in randomized blocks, arranged as a 3 x 5 factorial combination, was used with four replications. Treatments consisted of three cover plant species: millet (Pennisetum americanum), brachiaria (Brachiaria brizantha), and […]

It is well-known that Amazon tropical forest soils contain high microbial biodiversity. However, anthropogenic actions of slash and burn, mainly for pasture establishment, induce profound changes in the well-balanced biogeochemical cycles. After a few years the grass yield usually declines, the pasture is abandoned and is transformed into a secondary vegetation called “capoeira” or fallow. The aim of this study was to examine how the clearing of Amazon rainforest for pasture affects: (1) the diversity of the Bacteria domain evaluated […]