3308 results

Movement of a solute applied in two concentrations to an unsaturated soil via a disk permeameter

E. Borges, P. L. Libardi

01/Jun/2002

Groundwater pollution is one of the main factors justifying the study of soil solute movement and the processes of soil solute interaction. A deeper penetration than the expected of the chemicals applied to the soil surface, together with laboratory observations of the decrease of the amount of solutes in the solution passing through the soil, led researchers to consider the soil water (or solution) as having two phases: a mobile phase, θm, and an immobile phase, θim. In this paper, […]

Experimental use of ground-penetrating radar (GPR) to investigate tablelands in the northern coast of Bahia, Brazil

J. M. Ucha, M. Botelho, G. S. Vilas Boas, L. P. Ribeiro, P. S. Santana

01/Jun/2002

Nine profiles were studied along a toposequence developed on Barreiras Group sediments, in Fazenda Rio Negro, Entre Rios, Bahia, Brazil. Besides conventional analysis, an electromagnetic probe through GPR – Ground-Penetrating Radar was employed. The objective of this study was to analyze the use of this tool in the acquisition of information on features occurring underground, by comparing the radargrams and pedologic descriptions obtained in the area. The equipment used was a Geophysical Survey model, with an 80 MHz antenna. The […]

Rain erosivity and its distribution between 1989 and 1998 in the district of Lages, state of Santa Catarina, Brazil

I. Bertol, J. Schick, O. Batistela, D. Leite, D. Visentin, N. P. Cogo

01/Jun/2002

Water/Hydro-erosion comes as a result of rain erosivity and soil erodibility. Knowledge on erosivity is therefore useful as a guide for recommendations on management practices and soil conservation which have the aim to reduce hydro- erosion. Objectives of this study were the factor identification and quantification of natural rain erosivity in Lages, Santa Catarina, as well as knowledge on its temporary distribution. The study was carried out in 2000, using data on rainfall and soil loss of the period from […]

Detection of Azospirillum amazonense in roots and rhizosphere of orchidaceae and other plant families

A. Lange, F. M. S. Moreira

01/Jun/2002

Azospirillum amazonense is a widespread N2 fixing bacterium, occurring mainly in association with grasses and palm trees roots. Aiming to study its occurrence in species of other families not yet studied and the efficiency of media. Fam and LGI for its detection, these were used for rhizosphere soil counting or for enrichment cultures of rhizosphere soil, ecto and endorhizosphere. A. amazonense was detected in rhizosphere soil, ecto and endorhizosphere of many species belonging to monocotyledons, including Orchidaceae and dicotyledons with. […]

Summer legumes intercrops as a maize nitrogen source in southern Brazil

E. Spagnollo, C. Bayer, L. P. Wildner, P. R. Ernani, J. A. Albuquerque, M. M. Proença

01/Jun/2002

The use of legume cover crops contributes to soil conservation and would be an economical N source to maize. Since only winter legumes were evaluated in southern Brazil, this study was carried out to assess the effect of four intercropped summer species (Canavalia ensiformis, Cajanus cajan, Stizolobium niveum and Glycine sp.) on N supply and maize yield increase, in comparison with a control treatment, without legume cover crops. Cropping system effects on maize crop were evaluated under three mineral N […]

Iron oxidation on roots of two rice cultivars in flooded soil solution

G. Nava, H. Bohnen

01/Jun/2002

Rice cropped under waterlogged conditions may present symptoms of nutritional disorders similar to those caused by iron (Fe) toxicity. The symptoms do not occur in the same intensity in all cultivars and are more frequent in modern cultivars. The aim of our study was to evaluate the plant capacity of oxidizing reduced iron (Fe2+)on the root surface in green house conditions, comparing two rice cultivars (BR IRGA 409 and EPAGRI 108) with different degrees of susceptibility to iron toxicity and […]

Nutritional diagnosis of sugarcane in campos dos Goytacazes (RJ – Brazil)

R. A. Reis Jr., P. H. Monnerat

01/Jun/2002

The present study was conducted to evaluate the nutritional status of sugarcane in Campos dos Goytacazes, Rio de Janeiro, Brazil, by means of sufficiency range and Diagnosis and Recommendation Integrated System (DRIS). Foliar samples were collected in commercial sugarcane fields to evaluate the N, P, K, Ca, Mg, S, Cu, Mn and Zn concentrations. These foliar contents were compared to: (a) sufficiency range described in the literature, (b) average foliar concentration from a high-yielding group cultivated in Campos dos Goytacazes […]

Nitrogen application methods and their effects on nitrogen accumulation in corn plant

C. G. Bortolini, P. R. F. Silva, G. Argenta, E. L. Forsthofer

01/Jun/2002

Nitrogen accumulation in corn plant is highly influenced by N content in soil and by rate of its absorption by plant in a given growing stage. In order to compare the effects of N application methods on N accumulation and dry matter production by corn plant, an experiment was carried out in the state of Rio Grande do Sul, Brazil, over the 1998/99 growing season. Treatments consisted of two levels of water availability, one adequate to corn crop needs and […]

Incorporation of the bulk density to two models adjusted to the soil water retention curve

C. A. Tormena, A. P. Silva

01/Jun/2002

The soil water retention curve plays a fundamental role in the development of studies on the dynamics of soil water, modeling of physical soil processes and plant growth. The retention curve is usually obtained by simultaneously measuring water content (θ) and soil water potential (ψ) in a single sample. An alternative procedure is to use several samples per ψ to describe the retention curve. The use of this procedure requires that the variation factors which exist among the samples are […]

Agronomic alternative use for the biosolid generated in the Federal District. I – its effect on corn production and heavy metal incorporation in a cerrado oxisol

J. E. Silva, D. V. S. Resck, R. D. Sharma

01/Jun/2002

Brasilia’s urban growth has caused the increase of domestic sewage sludge, production generating a large volume of biosolid – a final product of sludge treatment – deposited at the Companhia de Saneamento de Brasilia (CAESB) sewage treatment plants. Although there is still a lack of technical data on health, environmental safety and economic viability, it has been used as a soil amendment and fertilizer by farmers in the neighbouring areas. The biosolid produced at one of the sewage treatment plants […]

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