Alterations in soil surface roughness by tillage and rainfall in relation to water erosion
01/Apr/2006
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 […]
Oxisol toposequences developed from basaltic rocks in Paraná State, Brazil. II – relationship between clay fraction mineralogy and physical soil properties
01/Apr/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 […]
Absorption, translocation and utilization of zinc, copper and manganese in grafted seedlings of Coffea arabica
01/Apr/2006
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 […]
Microbial biomass and light organic matter in soils under organic and conventional systems in the Chapada da Ibiapaba – CE, Brazil
01/Apr/2006
Several studies reveal that the substitution of native vegetation by agricultural systems results in decreases in the C and N soil organic matter pools. Aiming to test the hypothesis that management practices favoring organic residue inputs promote increases in the most sensitive organic matter pools, the present study intended to study areas of an organic management system of acerola fruit production and a conventional cultivation area cropped with carrot and beet in crop rotation with corn. These areas belong to […]
Preliminary evaluation of acid mine drainage in Minas Gerais State, Brazil
01/Apr/2006
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 […]
Decomposition and nutrient release of perennial herbaceous legumes intercropped with banana
01/Apr/2006
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 […]
Phosphorus deficiency symptoms in soybean
01/Apr/2006
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 […]
Heavy metals availability for corn cultivated in a Latosol sucessively amended with sewage sludges
01/Apr/2006
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 […]
Inoculant and foliar fertilizer in soybean under no-tillage cultivated in areas with established Bradyrhizobium populations
01/Feb/2006
This study was carried out in 1996/97, 1997/98 and 2000/01 crop seasons in Cruz Alta, state of Rio Grande do Sul, Brazil, aiming at evaluating the efficiency of commercial inoculant formulations, isolated and in combination with Mo and Co foliar fertilizer in an area that has been under no tillage for eight to twelve year and where Bradyrhizobium had already been established. In the 1996/97 crop year, the treatments were: non-inoculated control; 200 kg ha-1 of nitrogen fertilizer, split twice […]
Soil physical attributes and citrus root system distribution as indicators of cohesive layers in soils of coastal table lands in the state of Bahia, Brazil
01/Feb/2006
The physical characterization of two typical Coastal Tableland soils (Yellow Latosol-YL and Gray Argisol-GL) of the State of Bahia, Brazil, was carried out in 2001 and the citrus root system in such soils was evaluated in order to determine attributes that best identify the cohesive layer. The first four horizons in each soil were sampled for analysis of particle size distribution, soil bulk density, total porosity, macroporosity, microporosity, and saturated hydraulic conductivity. Soil resistance to penetration and critical humidity of […]
