Volume 30, Number 2, 2006

Soil structure (type, size and development) defines the total soil porosity and macro and microporosity distribution, and is considered to be one of the most important agricultural soil properties. The aim of this work was to study the effect of the clay fraction mineralogy, including the crystallographic mineral characteristics, in the soil physical properties of two Oxisols developed from the basaltic rocks, in different landscape positions (toposequence) in Paraná State, Brazil. With this objective, the soil profile was morphologically described […]

Evaluating the decomposition of cover crop residues added to the soil allows improving the comprehension of appropriate nutrient supply for commercial crops. This study was carried out under field conditions aiming to evaluate the decomposition and nutrient release from the shoots of perennial herbaceous legumes. The treatments were green cover crops intercropped with banana: groundnut (Arachis pintoi Krapov. & W.C. Gregory.), tropical kudzu (Pueraria phaseoloides (Roxb.) Benth.), siratro (Macroptilium atropurpureum (Sessé & Moc. ex DC.) Urb.) and spontaneous vegetation (mainly […]

Both soil conservation and crop productivity may negatively be affected by changes caused to soil characteristics by management techniques. The objective of this study was to evaluate the influence of soil tillage on soil physical attributes and organic carbon contents. The experiment was carried out over a period of 17 years in Eldorado do Sul County (RS) in a loamy Acrisol under different management systems: conventional tillage, reduced tillage and no-tillage, using vetch-maize in crop succession. An area of native […]

Although being temporary, the presence of tillage-induced surface roughness in the soil is an important requirement in conservation tillage systems. The reason is that surface roughness increases both surface retention and surface infiltration of water in the soil, reduces runoff velocity and volume, and traps eroded sediments, thus reducing water erosion damages. With this in mind, this study was developed with the objective of evaluating modifications in soil surface roughness by tillage and rainfall actions related to water erosion, in […]

This study carried out in order to evaluate the effect of sewage sludge (from Barueri: industrial and residential sewage, and Franca (SP) State: residential sewage) doses on soil heavy metal contents and their availability to corn. Three successive experiments were installed in a Latosol at the Experimental Field of Embrapa Environment, in Jaguariúna (SP), from 1999 to 2001. The treatments investigated consisted of: control (without sewage sludge); mineral fertilization (NPK) recommended for corn; and application of both sewage sludge sources […]

Mining in the State of Minas Gerais-Brazil is one of the activities with the strongest impact on the environment, in spite of its economical importance. Amongst mining activities, acid drainage poses a serious environmental problem due to its widespread practice in gold-extracting areas. It originates from metal-sulfide oxidation, which causes water acidification, increasing the risk of toxic element mobilization and water resource pollution. This research aimed to evaluate the acid drainage problem in Minas Gerais State. The study began with […]

There are complexes feedback mechanisms involving the relationship rootstock/scion, whick can positively or negatively affect the plant nutrient efficiency use. The goal of the present work was to evaluate the efficiency of uptake, translocation and utilization of Zn, Cu and Mn in coffee seedlings. The experiment was carried out in a greenhouse over 170 days using circulating nutrient solution in pots with sand medium. Four Coffea arabica L. genotypes were used as grafts: Catuaí Vermelho IAC 15 and Oeiras MG […]

It was observed in an experimental soybean field in Botucatu County (SP), Brazil, that leaves presented yellowish color with purple shades in the leaflets and petioles at grain filling. These symptoms, although not described in soybean, were compatible with general descriptions of phosphorus deficiency. An experiment was conducted in pots with washed sand and nutrient solution to reproduce these symptoms in controlled conditions. Three soybean plants were grown per pot, in an uncontrolled environment. Phosphorus deficiency symptoms were first observed […]