Volume 29, Number 3, 2005

This study was carried out from 1994 to 1998 in the Agronomy experimental area at the University of Cruz Alta – UNICRUZ, Cruz Alta, State of Rio Grande do Sul, Brazil to evaluate the influence of five soil management systems on bulk density, porous space (total porosity, macro and microporosity) of an clayey Rhodic Hapludox, as well as their effect on soybean, wheat and corn yield. The experiment had a completely randomized block design with four replications. The following management […]

Tillage and plant species that compose the soil management and crop rotation systems have a pronounced effect on soil physical quality, especially on aggregate stability. This study aimed to evaluate the degree of aggregate stability of a soil cultivated under reduced tillage (RT) and conventional tillage (CT) using distinct summer cover crops. Two experiments were carried out in Chapecó, State of Santa Catarina, Brazil on a Hapludox under RT (1993-1998) and CT (1994-1998). Five crop systems were evaluated in each […]

Soil tillage and crop systems have significant influence on the soil structure, affecting water and air flow. The objective of this study was to evaluate the effects the management has on the soil properties of a Hapludox cultivated with maize intercropped with summer cover crops. Two experiments were carried out in Chapecó, State of Santa Catarina, Brazil under reduced tillage (RT) from 1993 to 1998 and conventional tillage (CT) from 1994 to 1998. Three cropping systems were evaluated under each […]

In the conventional tillage system the soil is mobilized, incorporating and distributing crop residues and fertilizers in the arable layer. In no-tillage systems, however, where no soil mobilization occurs, lime and fertilizers are applied on the soil surface, which combined with the maintenance of crop residues cover favor the formation of a gradient of nutrient and organic matter concentration in the superficial soil layer. In the present study it was evaluated the effect of these two tillage systems on the […]

The shear tension and soil cohesion are important soil physical properties. They are affected by management systems and the content of Fe, Si and Al oxides in the soil. The effects of different sugarcane management systems on the shear tension, angle of internal friction, soil cohesion, and the contents of Fe, Si and Al oxides in a Cohesive Yellow Argisol were studied in four areas of the Triunfo mill in Alagoas State, Brazil. The treatments consisted of an area cultivated […]

The suitability for reforestation of parts of the North Slope of the Tijuca neighborhood not covered by buildings, the Mangue and Cunha watersheds, was studied. The plan was to subsidize the “Mutirão” Reforestation Program of the Environmental Department of Rio de Janeiro Municipality. Nutrient deficiency, water deficiency, erosion susceptibility and management impediments were considered in the evaluation of land suitability. The limitation degrees were evaluated for the components of soil survey units, considering soil and landscape information from the available […]

The alteration of spatial distribution of plants is an option to increase the grain yield. For high-yielding materials more information about the influence of nitrogen fertilization is needed. Thus, the influence of row spacing, population densities and nitrogen rates on the leaf nitrogen concentration, estimated concentration of chlorophyll, number of grains per ear, mass of thousand grains, grain yield, and protein content were evaluated. This study was carried out in the 2000/2001growth season; the treatments were two row spacings (0.60 […]

The production of short-chain organic acids is favoured by anaerobic conditions in flooded soil during rice cultivation and they can be toxic for the crop. However, the amount of acids formed depends on the system used for the rice cultivation. In order to measure the amount and type of organic acids formed in three different systems (conventional tillage, no tillage and pre-germinated planting), soil solution samples were collected from two depths (2.5 and 5.0 cm) after 3, 5, 9, 11, and […]

The Amazon banana plant is of great socio-economical importance, despite its requirement for high agricultural input in order to obtain good yields. An association with arbuscular mycorrhizae fungi could minimize the crop’s nutritional needs in the poor soils of the Amazon. The present study aimed at verifying how the plant-fungus mycorrhizal symbiosis influences nutrient concentration in five varieties of adult banana plants cultivated in an acid Amazon Oxisol under field conditions. The banana plantation was defficient in macro (Ca, Mg […]