This study was conducted in order to verify the influence of induced chemical properties in standard kaolinite and samples of three soils from the State of Paraná, Brazil – Hapludox Haplohumox and Tropohumults – on the spectral reflectance obtained in laboratory using a spectroradiometer, adjusted from 400 to 2500 nm. The samples were treated with solutions of calcium acetate, sodium acetate and incubated with calcium carbonate and sodium bicarbonate. Higher spectral reflectance was observed in the samples treated with calcium […]

The objective of this study was to evaluate the influence of different agricultural uses on alterations in the attributes of a medium-textured Latosol, in the region of cerrado and, in turn, on the formation of compacted and/or dense layers in the subsurface. In April, 1994, six sites were selected in the counties of Uberlândia and Monte Alegre de Minas, State of Minas Gerais, Brazil, where the soil was sampled in trenches: CC (Canadá Farm, cerrado vegetation); CP ( Canadá Farm, […]

One of the alternatives to diminish the urban waste volume to be discarded is the composting process, whose final product – the compost – can be used in agriculture. However, these composts may present toxic substances for humans, i.e. heavy metals. The aim of this study was to evaluate the chemical composition of waste composts from six Brazilian capitals. Samples of cattle manure, lime, ordinary phosphate, potassium chloride, and urea were analysed to compare with the waste compost. Determinations of […]

Acid phosphatase activity was evaluated in leaf extracts of four year old peach palms (Bactris gasipaes Kunth) in January, 1995. Plants from four progenies were field-grown under the combination of two levels of phosphorus (P1 = 0 and P2 = 200 kg ha-1 year-1 of P2O5) and two levels of nitrogen (N1 = 0 and N2 = 400 kg ha-1 year-1 of N). Potassium was applied at a rate of 200 kg ha-1 year-1 of K2O. The results of acid […]

Responses to phosphate fertilizing by vernalized garlic (Allium sativum, variety Roxo Perola de Caçador) were studied. To determine the calibration curve for phosphorus extracted with ion exchange resin, five soils of different textural groups, with and without organic fertilizer, were utilized. Two experiments, placed in 16 L pots, were carried out under greenhouse conditions, in the county of Botucatu, State of São Paulo, Brazil, from May to October, 1995 and 1996. Each of these experiments consisted of five soils at […]

An experiment was carried out in January of 1994, in the greenhouse of the Crop Science Department of the Universidade Federal de Viçosa, located in the Zona da Mata, State of Minas Gerais, Brazil (651 meter mean altitude) to evaluate the effect of aluminum on growth and development of nine coffee genotypes. Coffee plants with two pairs of fully expanded leaves were submitted to 0 and 0.296 mmol L-1 of aluminum in nutrient solution with pH 4.0 for 115 days. […]

This study was carried out using soil samples collected from a Podzol grown with orange trees, at Estação Experimental de Umbaúba, Umbaúba-SE (CPATC-EMBRAPA), to evaluate the acid and alkaline phosphatases activities from a coastal tableland soil submitted to different base saturation values (32, 45, 68 and 76.6%) and the relationships between soil characteristics and these activities. Positive responses to the increment of base saturation were observed for pH, organic matter content, available phosphorus and acid and alkaline phosphatases activities, in […]

The rates and the application time of nitrogen (N) may influence the agronomic characteristics of irrigated wheat (Triticum aestivum L.) and, consequently, grain yield. Two experiments were conducted at the Experimental Station of the Universidade Federal de Viçosa, located in Coimbra-MG, Brazil, during the years 1995 and 1996. The treatments consisted of a combination of four rates of N (30, 60, 90 and 120 kg ha-1), four rates of parceling (total rate at 20 days after emergence (DAE); ½ at […]

The effects of continuous sugarcane cropping on the properties of a clayey Yellow Latosol were studied in the region of the Low Coastal Tablelands of Alagoas State, Brazil. Four sites were selected at Caeté mill, São Miguel dos Campos, AL, involving a native forest (Tn) and sugarcane fields cultivated for periods of two (T2), eighteen (T18) and twenty-five (T25) years. The soils were morphologically characterized and undisturbed samples of the A, AB, and BA horizons of each profile were collected […]

The best measures of crop residue quality for soil protection against erosion are the percentage of soil cover and its persistence on the soil surface. These two variables, in turn, may be strongly affected by soil tillage. This study was carried out in Rio Grande do Sul State, Southern Brazil (30°06’S; 51°39’W). Crop residue mulch persistence was evaluated over a fallow period, following the harvest of a soybean crop. Three conservation tillage methods (chiseling, disking, and no-till) were used as […]