Volume 37, Number 2, 2013

On the soil surface, rainfall modifies the soil surface structure promoting crust development. This study evaluated the dynamics of soil crusting, through description and micromorphological analysis of thin sections in 2009 and 2010. In 15 x 30 m plots, the management systems conventional tillage (CT), reduced tillage (RT) and no tillage (NT) were assessed. Within the plots, 1 x 1 m micro-plots were installed to test different levels of simulated rainfall (0, 27, 54, and 80 mm) at an intensity […]

Soil water infiltration modeling is an important tool to predict soil water redistribution, soil erosion, aquifer recharge and aquifer contamination. This paper presents a model to simulate soil water infiltration (GAML-c), based on the Green-Ampt-Mein-Larson (GAML) model that provides a description of the geometry and advance of the wetting front in the soil. Experimental infiltration tests were performed in Red-Yellow Oxisol (LVA). GAML-c was evaluated in four scenarios: considering hydraulic conductivity (K0) equal to the stable infiltration rate (Tie) and […]

Is it possible to build predictive models (PMs) of soil particle-size distribution (psd) in a region with complex geology and a young and unstable land-surface? The main objective of this study was to answer this question. A set of 339 soil samples from a small slope catchment in Southern Brazil was used to build PMs of psd in the surface soil layer. Multiple linear regression models were constructed using terrain attributes (elevation, slope, catchment area, convergence index, and topographic wetness […]

Paddy rice fields may contribute to methane (CH4) emission from soil due to anaerobic conditions after flooding. Alternatives to continuous flooding irrigation in rice have been developed to mitigate CH4 efflux into the atmosphere. This study aims to investigate the effects of irrigation managements in the CH4 efflux during the rice growing season. An experiment was carried out at in Santa Maria, Rio Grande do Sul State, Brazil, during 2007/08 and 2009/10 growing seasons. The treatments were continuous flooding and […]

In addition to the more reactive forms, metals can occur in the structure of minerals, and the sum of all these forms defines their total contents in different soil fractions. The isomorphic substitution of heavy metals for example alters the dimensions of the unit cell and mineral size. This study proposed a method of chemical fractionation of heavy metals, using more powerful extraction methods, to remove the organic and different mineral phases completely. Soil samples were taken from eight soil […]

Considering nitrogen mineralization (N) of soil organic matter is a key aspect for the efficient management of N fertilizers in agricultural systems. Long-term aerobic incubation is the standard technique for calibrating the chemical extraction methods used to estimate the potentially mineralizable N in soil. However, the technique is laborious, expensive and time-consuming. In this context, the aims of this study were to determine the amount of soil mineralizable N in the 0-60 cm layer and to evaluate the use of […]

Common bean is traditionally grown on small farms in Brazil, where animal wastes are often used as soil fertilizer. Since this is a short-cycle species, nutrients must be available soon after seed germination, which is not always the case when supplied in the form of organic fertilizers. This study was carried out to evaluate the efficiency of different poultry litters in comparison with mineral fertilizers to increase dry matter yield and nutrient release to beans. The experiment was conducted in […]

Phosphorus (P) applications to vineyards can cause P accumulation in the soil and maximize pollution risks. This study was carried out to quantify the accumulation of P fractions in sandy soils of vineyards in southern Brazil. Soil samples (layers 0-5, 6-10 and 11-20 cm) were collected from a native grassland area and two vineyards, after 14 years (vineyard 1) and 30 years (vineyard 2) of cultivation, in Santana do Livramento, southern Brazil, and subjected to chemical fractionation of P. Phosphorus […]

The use of phosphite as a fungicide or supplementary source of phosphorus (P) has been intensified in recent years, however, little is known about its effects on important crops such as common bean. This work aimed to evaluate the effect of phosphite on growth and phosphate nutrition of bean plants. Two experiments in an completely randomized design were conducted in nutrient solution in a green house, from January to March 2008. In the first experiment, the treatments consisted of a […]

The no-tillage (NT) management is widely used in the Cerrado region, but some questions remain unanswered, for example about the need of liming and adequate nitrogen rates for commercial crops when preceded by cover crops. Our objective was to evaluate the effect of precedent cover crops on the maize demand for nitrogen fertilization and forms of liming preceding the adoption of no-tillage management (NT) in different growing seasons. The experiment was arranged in a randomized block factorial design 5 x […]