The inadequate use of soils induces alterations, exhausting the productivity, and resulting in growing areas of degraded soil. This study had the objectives of a) studying alternatives to promote the formation of the A horizon of a degraded soil through the use of green manure, sewage sludge, and cultivation of a native tree species; and b) selecting soil quality indicators to detect the alterations in the surface layer. Evaluations were executed annually. The experimental design was in random blocks with […]

Different physical properties are used to evaluate the soil physical quality. In this context, soil tensile strength and friability are indicators of the soil physical and structural quality. The objective of this study was to quantify the tensile strength and friability of an Oxisol under different soil use systems: forest, fallow and cultivated. Soil samples were collected from three contiguous areas of an Experimental Farm of the State University of Maringá. Two areas were cultivated: one with annual crops under […]

Manganese (Mn) toxicity may be a constraint for crop production in acid soils of tropical regions. However, variations of Mn concentrations in plant tissues are also related to the genotypic differences. A greenhouse experiment was carried out to evaluate Mn tolerance of three soybean cultivars [Glycine max (L.) Merrill]. Cultivars Santa Rosa, IAC-15 and IAC-Foscarin 31 were evaluated under five Mn rates (2, 100, 150, 200, and 250 µmol L-1) in nutrient solution (pH 5.0). The experiment in randomized blocks was a 5 x 3 factorial […]

Planter machines, responsible for the correct placing of seeds and fertilizer in the ground, have dosing mechanisms set in motion by the drive wheels, as they rotate in function of the contact with the ground surface. This contact is influenced, among other factors, by tire pressure. The objective of this work was to study the performance of a planter as affected by soil tillage, machine speed and planter tire pressure. The following variables were evaluated: traction force and drawbar pull, […]

The objective of this study was to evaluate the physical, chemical, mineralogical and micromorphological characteristics of cohesive red, yellow and grayish soils in a toposequence of the Coastal Tablelands region in southern Bahia and northern Espirito Santo states. It was also sought to understand the mechanisms promoting their cohesion and fragipan formation. Therefore, the routine physical analyses, determination of the coarse clay/fine clay ratio, specific surface by BET-N2 and water vapor adsorption, magnetic susceptibility, scanning-electron microscopy analyses and the micromorphology […]

The content and shap of clay minerals are important in the definition of soil structure morphology. To evaluate the clay mineralogy and chemical properties of different aggregate size-classes of Latosols (Red-Yellow – LBd and Dusky Red – LVdf) derived from basalt in the state of Paraná, Brazil, soil samples of the Bw1 and Bw2 horizons were collected in four LBd and three LVdf profiles, distributed across two distinct toposequences. Dried and undisturbed soil samples were separated into six size-classes (2-4; […]

The chlorophyll meter (SPAD-502, Minolta) is a portable device that measures the relative chlorophyll index (RCI) in a simple, fast and non-destructive way in the field. This index is correlated with leaf N concentration in several crops, and allows the correction of N deficiency, optimizing fertigation. The objective of this study was to test RCI as an indicator of the nitrogen status in coffee trees to adjust fertigation during the development cycle. The experiment was carried out in Botucatu, state […]

The use of electrochemical attributes has been suggested by a number of authors to characterize the colloidal soil compound and to serve as evaluation indices of certain properties related to plant fertility and nutrition and to pedogenesis, underlying regional soil differentiation. In this study, the relations between the point of null saline effect (PESN) and chemical properties of three Oxisols of a toposequence in the microbasin Chico Nunes, Mato Grosso were evaluated. Surface and subsurface samples were submitted to chemical, […]

In this study the distribution of lipid compounds was evaluated in sediment samples of an archaeological site Rio do Meio, Santa Catarina Island, Brazil. In the total lipid extracts, analyzed by gas chromatography and mass spectrometry (GC and GC-MS), saturated fatty acids and alcohols were predominant. At least two sources of organic matter were detected, an older and a more recent one. In the old deposit, the most abundant lipids were short-chain fatty acids (< Ac20:0), followed by a minor composition […]

It is necessary to evaluate the soil physical and chemical attributes in studies that explore grazing systems intensively. In this work the variation in physical and chemical attributes of an Alfissol cultivated with Panicum maximum Jacq. cv. IPR-86 Milênio under grazing were evaluated from October 2001 to May 2002, in the fifth year of consecutive N application at rates of 0, 150, 300, and 450 kg ha-1. After five successive applications of 450 kg ha-1 N, the OM content increased 5 g dm-3, which resulted in […]