This field study had the following objectives: to determine the most appropriate micronutrient extractor to evaluate manganese bioavailability in soils under no-tillage; to evaluate the interaction of soil manganese with humic acids in soils under no-tillage with and without manganese deficiency through electronic paramagnetic resonance (EPR); and to evaluate manganese fractions (exchangeable, organic, oxides and residual) after manganese addition in soils under no-tillage with and without previous manganese deficiency for soybean. Four sites (I to IV) were selected to study […]

The no-tillage system improves the structural soil quality. However, machinery traffic can cause surface soil compaction. In this situation, soil tilling for lime incorporation not only corrects soil acidity problems, but also decreases possible negative effects of soil compaction. The effects of tilling or not tilling the soil at the moment of lime reapplication on physical attributes in the soil profile and crop yields under different soil management systems were therefore evaluated. A long-term experiment was conducted on a Rhodic […]

The effects of soil fertility levels, root pruning and localized fertilization on root and shoot growth in ‘Catuaí’ coffee plants were studied in a greenhouse experiment. Sub-superficial (30-70 cm) samples of a Red-Yellow Latosol (Oxisol) were packed in PVC columns consisting of three 15 cm high rings of 20 cm diameter. Four treatments with three fertility levels [low (FB), medium (FM) and high (FA), and medium without root pruning with only two rings (FM2)] were installed before planting by adding […]

Maize genotypes with contrasting genetic variability have different yield potential. This distinct yield potential may be partially caused by differences in the root system morphology or in the nutrient uptake kinetics parameters. This study aimed to assess such morphological and physiological plant attributes of three maize genotypes with different genetic bases. A single-cross hybrid (P32R21), a double-cross hybrid (Traktor) and an open-pollinated variety (BRS Planalto) were studied. The uptake kinetics parameters (maximum influx – Imax, Michaelis-Mentem constant – Km, and […]

Acid drainage is an environmental problem, not exclusive, but commonly associated to coal mines. It arises from the oxidation of sulfides, like pyrite, in overburden and mining tailings. The use of ashes from coal combustion is still limited in Brazil, but such residues have a potential use as neutralizing agent for acid mine drainage. This study intended to evaluate the interaction between the use of coal ash and CaCO3 to neutralize acid drainage from pyrite oxidation in coal mining overburden […]

The use of pig slurry in no-tillage systems is relatively recent in South Brazil, so it is important to evaluate the decomposition of pig slurry as well as its effects on the cover crop residue decomposition in this system. The objective of this study was to evaluate the pig slurry decomposition and its influence on the decomposition rate of black oat straw in a soil under no-tillage. Two experiments were carried out under field conditions in an experimental area of […]

This study was carried out in 1996/97, 1997/98 and 2000/01 crop seasons in Cruz Alta, state of Rio Grande do Sul, Brazil, aiming at evaluating the efficiency of commercial inoculant formulations, isolated and in combination with Mo and Co foliar fertilizer in an area that has been under no tillage for eight to twelve year and where Bradyrhizobium had already been established. In the 1996/97 crop year, the treatments were: non-inoculated control; 200 kg ha-1 of nitrogen fertilizer, split twice […]

The physical characterization of two typical Coastal Tableland soils (Yellow Latosol-YL and Gray Argisol-GL) of the State of Bahia, Brazil, was carried out in 2001 and the citrus root system in such soils was evaluated in order to determine attributes that best identify the cohesive layer. The first four horizons in each soil were sampled for analysis of particle size distribution, soil bulk density, total porosity, macroporosity, microporosity, and saturated hydraulic conductivity. Soil resistance to penetration and critical humidity of […]

The biodegradability and distribution of pesticides in the environment determine their pollution potential. The risk of contamination with atrazine herbicide was studied in an Ultisol under field conditions and complemented with a microcosm system study. This system allowed the use of 14C-atrazine under controlled conditions and to determine of the volatilization (0.33%), mineralization (0.25%) and leaching (4 to 11%) parameters, which are difficult to evaluate in the field. Ninety percent of the radioactivity remained in the soil, with 75% in […]

Little is known about chemical and mineralogical attributes of soils from the upper Amazon, compared with well-studied soils from the middle and lower Amazon. In the well-drained uplands of Upper Amazon, due to the Andes Cordillera proximity, soils are expected to be chemically richer. This work aimed to increase the knowledge of soils from the upper Amazon, by means of studying three soils along a typical topossequence at Benjamin Constant, near the Brazilian-Peruvian Border. These soils range from the uplands, […]