The sustainability of irrigated rice (Oryza sativa L.) in lowland soils is based on the use of crop rotation and succession, which are essential for the control of red and black rice. The effects on the soil properties deserve studies, particularly on soil compaction. The objective of this study was to identify compacted layers in an Albaqualf under different cultivation and tillage systems, by evaluating the soil bulk density (Ds) with Gamma Ray Computed Tomography (TC). The analysis was carried […]

The porosity of the clay fraction is very important for the understanding of the physicochemical phenomena which are relate to the specific surface area of solid particles. The specific surface area (SBET) and porosity of clay fractions of two Rhodic Ferralsols in the state of Mato Grosso do Sul, Brazil, natural kaolinite (KGa2), synthetic goethite (Gt) and hematite (Hm) were evaluated through adsorption and desorption isotherms of N2.. Results concerning SBET and particle porosity were related to the maximum P […]

Peat bogs are Organosols formed under ideal ecological conditions in terms of the accumulation of organic material, controlled by geomorphological and geological processes and climate. The physical, chemistry and biological constitution of peat bogs is largely unknown. In this study the peat bogs of the Southern Serra do Espinhaço (Minas Gerais, Brazil) were described and sampled from three profiles at 1,250 m (P1), 1,350 m (P4) and 1,800 m (P2) above sea level. The three profiles were characterized morphologically, the […]

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 […]