Volume 25, Number 4, 2001

The spatial variability of soil water infiltration rate and A horizon thickness were studied in a Red-Yellow Podzolic soil (Kandudalf) showing erosion signs, located in Vera Cruz, SP. Field measurements were taken in regular 5 meter spacing square grid, resulting in 64 sampling points where the infiltration rate at the A, E and B horizon, and A horizon thickness were determined in coffee, pasture and natural vegetation. Statistical analysis showed high variability in the soil water infiltration rate and in […]

This study presents the use of geostatistical analyses for the design of sampling schemes, focusing specially on the anisotropy impacts on the dimensioning of sample units and image generation techniques. The attribute studied was the superficial clay content, measured during November 1998 in a Typic Hapludox, in Campos Novos Paulista (SP). Spatial variability and anisotropy of clay content were determined by examining the semivariograms, which were fit to theoretical models to obtain its parameters (variogram model type, nugget, sill and […]

Grapevine nutrition is a fundamental factor for quality production. Often, for physiological mainly nutritional reasons, problems of reduced bud break occur, reflecting in grapevine productivity. This experiment was carried out to evaluate the effectiveness of the foliar formulation of macro and micronutrients, activated with polihexose in grapevine production, during two years, in a vineyard of the cv. Merlot grafted in the rootstock R110, formed in lira system, located in Monte Belo do Sul (RS), Brazil. Eleven treatments were used, consisting […]

This study was carried out in the Western region of Minas Gerais, Brazil to evaluate the morphological changes in a Yellow-Red Latosol, after a conversion of a 20 year old Brachiaria decumbens pasture, under intensive pasture systems; a pure Brachiaria decumbens and an association of this grass with the legume Stylosanthes guianensis. Through morphological and physical characterization, it could be concluded that: (a) there were structural obstructions to radicular development in the old pasture soil; (b) the soil macrofauna played […]

Calcium deficiency and aluminum toxicity are considered to be the most important acidity factors limiting root growth. A field experiment was carried out on a dystrophic Red Latosol (Haplortox) in Ponta Grossa, Paraná, Brazil, to study the effects of surface application of lime and gypsum on root growth and nutrient uptake by soybean, cv. EMBRAPA 58, under no-tillage system. A randomized complete block design was used, with three replications, in a split-plot experiment. Dolomitic limestone was applied at rates of […]

Erosion control benefits provided by conservation tillage can be diminished if mulch fails or loses its effectiveness. A field experiment was carried out at the Agriculture Experimental Station of the Federal University of Rio Grande do Sul in Eldorado do Sul, RGS, Brazil, on a 0.105 m m-1 slope, sandy loam Ultisol, to investigate mulch failure for different forms of residue management under no-till system. Simulated rainfall (63.5 mm h-1) was applied with the rotating-boom rainfall simulator until steady-runoff rates […]

Tebuthiuron adsorption was determined in samples from 0-10 to 10-20 cm layers of three soils from the county of Ribeirão Preto (SP)-Brazil: Quartzarenic Neosol (Entisol), Red Latosol dystrofic and Red Latosol dystroferric (Oxisols). Sorption data were obtained by batch equilibrium and fitted to four adsorption models: Freundlich, linear, Langmuir and Lambert. Several statistical criteria were applied for selection among these isotherms. Freundlich model showed the best fit to the data. Kd values ranged from 0.723 to 2.573 L kg-1, and […]

This work aimed to evaluate the efficiency of two leguminous and two grass species in improving soil chemical characteristics (organic carbon, effective, and potential CEC and available levels of P, K, Ca, Mg, H and pH) as a function of the depth and position of the sample collection. The experiment design was a split plot in a factorial scheme. The plot was previously used for studies of soil losses by erosion, and the soil classified as “Nitossolo Vermelho Eutrófico”, loamy […]