Consulta: subjectFacets:"Aggregates"
Registros recuperados: 10
Data/hora: 01/06/2024 09:55:15

Impacto de las prácticas antrópicas en los suelos del distrito de riego "Los Insurgentes", México.
Provedor de dados: 32
Autores: Reséndiz Paz, Ma. de la Luz.
Los suelos del distrito de riego “Los Insurgentes”, Estado de México, fueron diagnosticados como salinos durante su establecimiento en 1976, además reciben las aguas residuales no tratadas de la ciudad de México. Sin embargo, el paisaje actual es predominantemente agrícola. Con la finalidad de conocer las estrategias que permitieron la rehabilitación de estos suelos y su impacto en las propiedades edáficas, clasificación y calidad agrícola, se llevó a cabo la presente investigación. Se realizó un levantamiento etnoedafológico con el que se obtuvieron: a) las estrategias que permitieron recuperar los suelos, y b) un mapa con las clases de tierras locales que se utilizó como base para identificar perfiles modales para la clasificación de los suelos y para...
Palavras-chave: Antrosoles; Levantamiento etnoedafológico; Clasificación de suelos; Aguas residuales; Calidad agrícola edáfica; Sodicidad; Agregados; Mineralogía del valle de México; Anthrosols; Etnopedological survey; Soil classification; Untreated wastewater; Agricultural soil quality; Sodicity; Aggregates; Mineralogy of the valley of Mexico; Edafología; Doctorado.
Ano: 2012
URL: http://hdl.handle.net/10521/721

Suspended sediments in a macrotidal estuary: comparison and use of different sensors
Provedor de dados: 5
Autores: Lunven, Michel; Gentien, Patrick.
Measurements made using an in situ particle-sizer (PSA) were compared to those of an optical backscatter sensor (OBS) in a macrotidal estuary. Both estimate the total volume of particles. After comparison with dry weight of suspended matter sampled in the study area, the different measurements were converted into dry weight. In three different kinetic energy regimes, times series were coherent for most of the observations. Discrepancies of suspended sediment concentrations estimated by both sensors appeared under specific hydrodynamic conditions: they were related to occurrences of definite particle populations. Overestimations and underestimations of measurements by the instruments depend on the optical principles of the sensors (backscatter and...
Tipo: Text
Palavras-chave: Particle size; Suspended particulate matter; Aggregates; Taille de particule; Matières en suspension; Agrégats.
Ano: 2000
URL: http://archimer.ifremer.fr/doc/2000/publication-521.pdf

Interactions between polystyrene microplastics and marine phytoplankton lead to species-specific hetero-aggregation
Provedor de dados: 5
Autores: Long, Marc; Paul-pont, Ika; Hegaret, Helene; Moriceau, Brivaela; Lambert, Christophe; Huvet, Arnaud; Soudant, Philippe.
To understand the fate and impacts of microplastics (MP) in the marine ecosystems, it is essential to investigate their interactions with phytoplankton as these may affect MP bioavailability to marine organisms as well as their fate in the water column. However, the behaviour of MP with marine phytoplanktonic cells remains little studied and thus unpredictable. The present study assessed the potential for phytoplankton cells to form hetero-aggregates with small micro-polystyrene (micro-PS) particles depending on microalgal species and physiological status. A prymnesiophycea, Tisochrysis lutea, a dinoflagellate, Heterocapsa triquetra, and a diatom, Chaetoceros neogracile, were exposed to micro-PS (2 μm diameter; 3.96 μg L−1) during their growth culture...
Tipo: Text
Palavras-chave: Polystyrene; Microplastic; Aggregates; Microalgae; Marine; Phytoplankton.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00389/50016/50735.pdf

Construction Minerals in the Baltimore-Washington Metropolitan Area: A Land Management Analysis
Provedor de dados: 31
Autores: Wernstedt,   Kris; Cummings,   Amy Mcabee.
The patchwork of government influences that shape the protection and management of construction mineral resources--sand, gravel, and crushed stone--includes statutes, regulations, guidance documents, and court decisions at the federal, state, and local level. Across the Washington-Baltimore metropolitan area, both these influences and the experiences that the counties have had in managing construction mineral resources range widely. Our principal objective in this study is to discuss the mechanisms that counties use to manage such resources; the level and source of concern that local residents have with respect to construction mineral extraction operations; officials' perceptions about trends in the supply and demand for mineral resources; and the level of...
Tipo: Working or Discussion Paper
Palavras-chave: Construction minerals; Aggregates; Land use planning; Baltimore-Washington; Land Economics/Use; Q24; Q38; R52.
Ano: 1999
URL: http://purl.umn.edu/10731

A note on the environmental costs of aggregates
Provedor de dados: 31
Autores: Berck,   Peter.
The opening of a new site for the production of aggregates has both direct and indirect impacts on the environment. The indirect impacts include changes in the environmental costs of hauling aggregates and possible changes in the level of construction activity. In this note, we show that the most likely effect of a new aggregate site is to reduce the truck miles used for aggregate hauling, which is an environmental benefit. We also show that the change in construction activity induced by a new site is likely to be extremely small.
Tipo: Working or Discussion Paper
Palavras-chave: Aggregates; Building materials; Costs; Environmental aspects; Environmental Economics and Policy.
Ano: 2005
URL: http://purl.umn.edu/43918

Mineralogy of the clay fraction of alfisols in two slope curvatures: IV - spatial correlation with physical properties
Provedor de dados: 90
Autores: Camargo,Livia Arantes; Marques Júnior,José; Pereira,Gener Tadeu.
Although the influence of clay mineralogy on soil physical properties has been widely studied, spatial relationships between these features in Alfisols have rarely been examined. The purpose of this work was to relate the clay minerals and physical properties of an Alfisol of sandstone origin in two slope curvatures. The crystallographic properties such as mean crystallite size (MCS) and width at half height (WHH) of hematite, goethite, kaolinite and gibbsite; contents of hematite and goethite; aluminium substitution (AS) and specific surface area (SSA) of hematite and goethite; the goethite/(goethite+hematite) and kaolinite/(kaolinite+gibbsite) ratios; and the citrate/bicarbonate/dithionite extractable Fe (Fe d) were correlated with the soil physical...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Aggregates; Mineral crystallinity; Density; Porosity; Penetration resistance; Cross-semivariogram.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832013000200002

Labile and stable fractions of soil organic matter under management systems and native cerrado
Provedor de dados: 90
Autores: Figueiredo,Cícero Célio de; Resck,Dimas Vital Siqueira; Carneiro,Marco Aurélio Carbone.
Soil organic matter can be analyzed on the basis of the different fractions. Changes in the levels of organic matter, caused by land use, can be better understood by alterations in the different compartments. The aim of this study was to evaluate the effect of different management systems on the labile and stable organic matter of a dystrophic Red Latosol (Oxisol). The following properties were determined: total organic C and total N (TOC and TN), particulate organic C and particulate N (POC and PN), organic C and N mineral-associated (MOC and NM) and particulate organic C associated with aggregate classes (POCA). Eight treatments were used: seven with soil management systems and one with native Cerrado as a reference. The experiment was designed to study...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Fractioning; Particulate organic carbon; Aggregates; No-tillage; Pasture.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832010000300032

Physical properties of soils under intensive agricultural management
Provedor de dados: 63
Autores: Soares,Jorge Luís Nascimento; Espindola,Carlos Roberto; Pereira,Walcylene Lacerda Matos.
Pedologic alterations after long-term sugar cane (Saccharum officinarum) cropping cycles under traditional soil management systems were studied on a farm in Bariri, SP, Brazil. A toposequence was established to evaluate the effects of the soil position in the relief in changing soil physical attributes. Morphological field descriptions and laboratory analyses were carried out on vertical profiles of the upper, middle and lower thirds of a Typic Haplorthox slope. Soil bulk density and macroporosity changed along the toposequence reflecting on soil hydrodynamics, especially in the lower slope parts. At sites with high clay levels, empty spaces were filled forming block shaped structures together with the micro-aggregate structure. The intensive cultivation...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Soil management; Toposequence; Aggregates; Soil micromorphology.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162005000200012

Gold phytoextraction and mining-degraded soil reclamation
Provedor de dados: 109
Autores: Ramírez Pisco,Ramiro; Gómez Yarce,Juan Pablo; Guáqueta Restrepo,Juan José; Gaviria Palacio,Daniel.
Abstract Gold phytoextraction is a technology used to obtain this metal (Au) throughout plants. Some of the benefits of this technology are the mitigation of the environmental impact, the fact that it does not imply the constant use of pollutants, and has the ability to promote soil reclamation. The aim of this research was to determine if Brachiaria decumbens has the potential to improve soil physical properties while had achieved a gold extraction. For this purpose, Helianthus annuus and Brachiaria decumbens, were used in a completely randomized design with four replicates. To induce gold uptake, ammonium thiocyanate was applied to plants. The statistical analysis was performed using the R-Studio software. Finally, it became evident that B. decumbens is...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Absorption; Aggregates; Transpiration; Roots.
Ano: 2017
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-28122017000400574

Análise micromorfométrica de agregados de um LATOSSOLO VERMELHO Distroférrico em diferentes sistemas de manejo - DOI: 10.4025/actasciagron.v31i1.6640
Provedor de dados: 1
Autores: Cremon, Cassiano; UNEMAT; Rosa Júnior, Edgard Jardim; UFMS; Serafim, Milson Evaldo; UFMS; Ono, Fábio Benedito; UFLA.
O objetivo deste trabalho é caracterizar micromorfometricamente os agregados de um Latossolo submetido a diferentes formas de manejo do solo. O trabalho desenvolveu-se em um LATOSSOLO VERMELHO Distroférrico, de Dourados, Mato Grosso do Sul. O delineamento experimental utilizado foi o de blocos casualizados com quatro repetições e os tratamentos foram arranjados em parcelas sub-subdivididas. Os tratamentos consistiram de dois sistemas de manejo (convencional e plantio direto), duas doses de gesso (zero e 2 t ha-1) e a utilização de duas culturas de verão (soja e milho). Os agregados foram coletados, nas profundidades de 0 a 10 e 10 a 20 cm, utilizando-se, nos procedimentos experimentais, os retidos no intervalo de diâmetro de 9,52 e 4,76 mm, após...
Palavras-chave: 5.02.01.07-7 Solos Florestais plantio direto; Imagens digitais; Agregados. no-tillage; Digital images; Aggregates.
Ano: 2009
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAgron/article/view/6640