3299 results

Pedogeochemical in alteration profiles in the region of Lavras, Minas Gerais. I- major elements – main oxides

M. P. C. Lacerda, H. Andrade, J. J. G. Quéméneur

01/Mar/2002

The geochemical behavior in soil alteration profiles in Lavras (MG), Brazil, was evaluated during the process of soil formation leading to the formation of argillic horizons, in parent material ranging from acid, intermediate to mafic geochemical composition.Along each profile, from the consolidated bedrock to the solum, geochemical analyses of major elements-main oxides were performed, calculating the gains and losses through a mass chemical balance.The results showed a moderate loss of SiO2, bases leaching, and a slight relative enrichment of Al, […]

Soil chemical changes and corn growth as affected by the addition of tannery sludges

E. E. Konrad, D. D. Castilhos

01/Mar/2002

This study was carried out to evaluate chemical changes and corn growth in an Albaqualf soil.The tannery wastes used were primary sludge with Cr at the rates of 13.8 and 27.6Mgha-1 corresponding to 250 and 500mgkg-1 of Cr soil, respectively, and the sludge from liming, at the rates of 10.25 and 20.50Mgha-1. The experiment was conducted in a greenhouse during 108days.The liming sludge increased pH (4.9 to 5.8), soil Ca (0.5 to 3.2cmolcdm-3) and resulted in corn yields similar to […]

Sorption-desorption of chlorothalonil in soils with different organic matter contents

J. B. Regitano, F. Prata, N. M. P. Dias, A. Lavorenti, V. L. Tornisielo

01/Mar/2002

Pesticide kinetics and sorption allow to predict the equilibrium time of the reaction and to speculate over the reaction mechanisms involved.Therefore, their study is fundamental to understand the environmental fate of pesticides.The aim of this research was to evaluate the sorption and kinetics of the fungicide chlorothalonil in five distinct soils with different organic matter contents of the state of São Paulo (Brazil): Neossolo Quartzarênico órtico (RQo), Latossolo Vermelho distroférrico (LVdf-1 e LVdf-2), Latossolo Vermelho perférrico (LVj), and Gleissolo (G).The […]

Relationships between the isomorphic substitution of Fe for Al and the chemical and mineralogical characteristics of synthetic hematites

J. A. Sambatti, A. C. S. Costa, A. S. Muniz, E. Sengik, I. G. Souza Junior, J. M. Bigham

01/Mar/2002

Hematites were synthesized with different degrees of isomorphic substitution (IS) of Fe for Al to a maximum of 16Almol%.The minerals were characterized by X-ray diffraction, total chemical analysis, extraction of iron and aluminum soluble in ammonium acid oxalate (Feo+Alo), determination of the anion exchange capacity (AEC) and specific surface area (SSA).The results showed that the synthesis methods resulted in a minimum amount of impurities and that, in a general way, the foreseen values of isomorphic substitution were achieved.The SSA values […]

Chemical changes in argisols under irrigated grape production in the central São Francisco river valley, Brazil

R. J. Heck, H. Tiessen, M. C. Santos, I. H. Salcedo, R. J. T. Alves

01/Mar/2002

This study compares the chemical composition of the solution and exchange complex of soil in a 3-year-old irrigated vineyard (Vitis vinifera L., Red Globe cultivar) with that of adjacent clearing in the native hyperxerophyllic ‘caatinga’ vegetation. The soils are classified as Plinthic Eutrophic Red-Yellow Argisol; according to Soil Taxonomy they are isohyperthermic Plinthustalfs. Detailed physiographic characterization revealed an impermeable gravel and cobble covering the crystalline rocks; the relief of this layer was more undulating than the level surface. Significant higher […]

Effects of soil disinfestation by solar energy on arbuscular mycorrhizal fungi

O. Randig, C. A. B. Medeiros, C. A. Sperandio

01/Mar/2002

Besides its low cost, solar energy use in soil disinfestation presents no risks for human health and the environment. However, its effects on beneficial microorganisms are not well known. This study evaluated the effect of a solar collector and solarization on an indigenous population of arbuscular mycorrhizal fungi. Inoculum potential of mycorrhizae, determined by the most probable number method, decreased, respectively, 93 and 99% when soil was treated during 30days by solarization and solar collector. Mycorrhizal colonization of maize plants, […]

Chemical properties and management of acid sulfate soils in lowlands of Coruripe river valley, Alagoas state, Brazil

V. S. Souza Júnior, M. R. Ribeiro, L. B. Oliveira

01/Dec/2001

Six soil profiles were selected in a drained lowland área at Coruripe sugarmill aiming to study chemical properties of acid sulfate soils occurring in the fluvial plain of the Coruripe river valley, Alagoas State, Brazil. The soils were morphologically characterized and samples were taken from each horizon to determine chemical properties of soil and saturation extract, using dry and wet samples (field conditions). A greenhouse liming experiment was carried out with compound samples collected at the sites of two selected […]

ZN, Cu and Cd effects on the behavior of ectomycorrhizal fungi in culture medium

P. H. Grazziotti, J. O. Siqueira, F. M. Moreira, D. Carvalho

01/Dec/2001

Ectomycorrhizal fungi are able to tolerate toxic heavy-metal concentrations in host plants, although being also negatively affected by excessive metal. Isolates of Pisolithus tinctorius and Scleroderma bovinus were grown for 20 days at 28°C in a liquid medium with increasing levels of Zn, Cu and Cd sulfates in 125 mL conical flasks containing 50 mL of MMN medium, adjusted to pH 4.8. Fungi growth was inhibited by heavy metal increasing concentration, which was different for fungi and metals. The 50% […]

Aluminum effect on the growth of two forest species

A. N. Beutler, L. A. Fernandes, V. Faquin

01/Dec/2001

An experiment was carried out at the Soil Science Department of Universidade Federal de Lavras, in Lavras (MG). in November 1998, to study the effect of aluminum on the initial growth of two forest species, under greenhouse conditions using a nutrient solution. After two weeks in dilute nutrient solution to 1/3 and without aluminum, two Moringa (Moringa oleifera) and two Angico (Anandenantha peregrina) plants were transplanted to 1.5 L pots, and grown in nutrient solution. The aluminum levels were 0.0, […]

Characterization and classification of acid sulfate soils in lowlands of Coruripe river valley, Alagoas, Brazil

V. S. Souza Júnior, M. R. Ribeiro, L. B. Oliveira

01/Dec/2001

Six soil profiles were selected in a drained lowland area at Coruripe Sugarmill, aiming to characterize acid sulfate soils occurring in the lowplain of the Coruripe River Valley, in the coastal humid zone of the state of Alagoas. The soils were morphologically characterized, and samples were taken from each horizon to determine particle size distribution, bulk and particle density, total porosity, pH (H2O and KCl), organic matter, exchangeable bases and CEC, soluble sulfate and electrical conductivity of the saturation extract. […]

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