Volume 35, Number 1, 2011

Detailed studies on hydrology and sediment production are of great value to enhance the understanding and control of the water erosion process, with a view to more continuous and effective soil and water conservation practices. The purpose of this study was to develop specific (for each treatment replication) hydrograms (instantaneous runoff discharge versus time) and sedimentograms (instantaneous sediment concentrations in the runoff and instantaneous soil loss rates versus time), associated with water erosion in a soil under different crop sequences […]

Nickel, although essential to plants, may be toxic to plants and animals. It is mainly assimilated by food ingestion. However, information about the average levels of elements (including Ni) in edible vegetables from different regions is still scarce in Brazil. The objectives of this study were to: (a) evaluate and optimize a method for preparation of vegetable tissue samples for Ni determination; (b) optimize the analytical procedures for determination by Flame Atomic Absorption Spectrometry (FAAS) and by Electrothermal Atomic Absorption […]

Adequate nutrient levels in plants vary according to the species or clone, age and management practice. Therefore, adjustments of the nutrient solution are often necessary according to the plant material for multiplication. This study aimed to evaluate the influence of NPK fertilization on production and leaf nutrient contents of eucalyptus cuttings in nutrient solution. The study was conducted from November 2008 to January 2009 in a greenhouse. The experimental design was completely randomized fractional factorial (4 x 4 x 4)1/2, […]

The definition of family settlement plots in land reform projects involves technical and social issues. These aspects are mainly related to differences in the agricultural suitability of the soil in these projects. The objective of this study was to introduce a procedure for an optimal subdivision of the land by cross-linking projects by a Genetic Algorithm (GA). The GA was tested in the rural settlement Veredas, located in Padre Paraíso, in the region of the Vale do Jequitinhonha, State of […]

An accurate estimation of hydraulic fluxes in the vadose zone is essential for the prediction of water, nutrient and contaminant transport in natural systems. The objective of this study was to simulate the effect of variation of boundary conditions on the estimation of hydraulic properties (i.e. water content, effective unsaturated hydraulic conductivity and hydraulic flux) in a one-dimensional unsaturated flow model domain. Unsaturated one-dimensional vertical water flow was simulated in a pure phase clay loam profile and in clay loam […]