981 resultados para Cape Bounty – Soil IOrganic Matter Characterization


Relevância:

30.00% 30.00%

Publicador:

Resumo:

In Spain, large quantities of wine are produced every year (3,339,700 tonnes in 2011) (FAO, 2011) with the consequent waste generation. During the winemaking process, solid residues like grape stalks are generated, as well as grape marc and wine lees as by-products. According to the Council Regulation (EC) 1493/1999 on the common organization of the wine market, by-products coming from the winery industry must be sent to alcohol-distilleries to generate exhausted grape marc and vinasses. With an adequate composting treatment, these wastes can be applied to soils as a source of nutrients and organic matter. A three-year field experiment (2011, 2012 and 2013) was carried out in Ciudad Real (central Spain) to study the effects of wine-distillery waste compost application in a melon crop (Cucumis melo L.). Melon crop has been traditionally cultivated in this area with high inputs of water and fertilizers, but no antecedents of application of winery wastes are known. In a randomized complete block design, four treatments were compared: three compost doses consisted of 6.7 (D1), 13.3 (D2) and 20 t compost ha-1 (D3), and a control treatment without compost addition (D0). The soil was a shallow sandy-loam (Petrocalcic Palexeralfs) with a depth of 0.60 m and a discontinuous petrocalcic horizon between 0.60 and 0.70 m, slightly basic (pH 8.4), poor in organic matter (0.24%), rich in potassium (410 ppm) and with a medium level of phosphorus (22.1 ppm). During each growing period four harvests were carried out and total and marketable yield (fruits weighting <1 kg or visually rotten were not considered), fruit average weight and fruit number per plant were determined. At the end of the crop cycle, four plants per treatment were sampled and the nutrient content (N, P and K) was determined. Soil samplings (0-30 cm depth) were carried before the application of compost and at the end of each growing season and available N and P, as well as exchangeable K content were analyzed. With this information, an integrated analysis was carried out with the aim to evaluate the suitability of this compost as organic amendment.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Debido al futuro incierto de la mayor parte de los fumigantes edficos usados actualmente en la Unin Europea, que pueden implicar riesgos para la salud humana/animal y el medio ambiente, es necesario desarrollar programas de manejo integrado para el control de plagas de cultivos. Estos programas se incluyen como obligatorios en el Reglamento (EC) No. 1107/2009. De acuerdo con este Reglamento, es obligatoria la evaluacin del riesgo asociado al uso de productos fitosanitarios sobre los organismos edficos no diana y sus funciones, adems de llevar a cabo ensayos con diferentes especies indicadoras para obtener datos de toxicidad que puedan ser usados posteriormente en la evaluacin de riesgo. Sin embargo, la baja representatividad de algunas de estas especies indicadoras en el rea Mediterrnea supone una gran limitacin. En esta situacin, el Panel Cientfico de Productos Fitosanitarios y sus Residuos de la Autoridad Europea en Seguridad Alimentaria (EFSA), ha sealado la necesidad de modificar los datos ecotoxicolgicos requeridos para evaluar los efectos adversos de los productos fitosanitarios de una manera ms integrada, incluyendo criterios funcionales y estructurales mediante organismos como bacterias, hongos, protozoos y nematodos. De este modo, la EFSA ha recomendado el uso de los nematodos en la evaluacin de la funcionalidad y estructura del suelo. Los nematodos estn globalmente distribuidos y son morfolgicamente diversos; esto junto con su gran abundancia y diversidad de respuestas a las perturbaciones edficas, los convierte en indicadores adecuados del estado del suelo. Puesto que los nematodos interaccionan con muchos otros organismos que participan en diferentes eslabones de la red trfica edfica, jugando papeles importantes en procesos edficos esenciales en los agroescosistemas, la diversidad de nematodos es, a menudo, usada como indicador biolgico de los efectos de las prcticas agrcolas en el estado del suelo. En los ltimos aos, diferentes ndices basados en la comunidad nematolgica han facilitado la interpretacin de datos complejos sobre la ecologa del suelo. Los ndices de la red trfica edfica, basados en la abundancia de grupos funcionales definidos como grupos C-P y grupos trficos, permiten la evaluacin de la funcionalidad de la red trfica edfica. Por otra parte, la dificultad en la identificacin taxonmica de nematodos para explicar su uso limitado como indicadores ecolgicos, es ampliamente discutida, y existe cierta controversia en cuanto a la eficacia de los diferentes mtodos de identificacin de nematodos. Se argumenta que la identificacin morfolgica es difcil y puede llevar mucho tiempo debido a la falta de expertos especializados, y se afirma que las tcnicas moleculares pueden resolver algunas limitaciones de las tcnicas morfolgicas como la identificacin de juveniles. Sin embargo, los mtodos de identificacin molecular tienen tambin limitaciones; la mayora de las bases de datos de secuencias de ADN estn fuertemente orientadas hacia los nematodos fitoparsitos, los cuales representan slo una parte de la comunidad edfica de nematodos, mientras que hay poca informacin disponible de nematodos de vida libre a pesar de representar la mayora de los nematodos edficos. Este trabajo se centra en el estudio de los efectos de fumigantes edficos en la funcionalidad del suelo a travs del uso de diferentes indicadores basados en la comunidad de nematodos, como los ndices de la red trfica, ndices de diversidad, abundancia de los taxones ms relevantes etc. Tambin se han analizado otros indicadores funcionales relacionados con la supresividad edfica, el ciclo de nutrientes o la actividad de la microfauna del suelo. En el captulo 1, la diversidad de nematodos estudiada en una explotacin comercial de fresa y sus alrededores durante dos campaas consecutivas en el suroeste espaol, fue baja en los suelos fumigados con fumigantes qumicos ambas campaas y, aunque se observ una recuperacin a lo largo de la campaa en la zona tratada, los suelos fumigados mostraron una condicin perturbada permanente. La comunidad de nematodos estuvo ms asociada al ciclo de nutrientes en la zona sin cultivar que en los suelos cultivados, y se observ poca relacin entre la biomasa de las plantas y la estructura de la comunidad de nematodos. Los surcos sin tratar dentro de la zona de cultivo funcionaron como reservorio tanto de nematodos fitoparsitos como beneficiosos; sin embargo estas diferencias entre los surcos y los lomos de cultivo no fueron suficientes para mantener la supresividad edfica en los surcos. Los suelos tratados fueron menos supresivos que los suelos sin tratar, y se observaron correlaciones positivas entre la supresividad edfica y la estructura de la red trfica edfica y la diversidad de nematodos. En el captulo 2, se evaluaron los efectos de dos pesticidas orgnicos con efecto nematicida y dos nematicidas convencionales sobre las propiedades fsico qumicas del suelo, la diversidad de nematodos y la biomasa de las plantas en condiciones experimentales en dos tipos de suelo: suelos agrcolas poco diversos y suelos provenientes de una zona de vegetacin natural muy diversos. El mayor efecto se observ en el tratamiento con neem, el cual indujo un gran incremento en el nmero de dauerlarvas en los suelos pobres en nutrientes, mientras que el mismo tratamiento indujo un incremento de poblaciones de nematodos bactervoros, ms estables y menos oportunistas, en los suelos del pinar ricos en materia orgnica. En el captulo 3, se compar la eficacia de mtodos moleculares (TRFLP, Terminal Restriction Fragment Length Polymorphism) y morfolgicos (microscopa de alta resolucin) para la identificacin de diferentes comunidades denematodos de Espaa e Irlanda. Se compararon estadsticamente las diferencias y similitudes en la diversidad de nematodos, otros indicadores ecolgicos y de la red trfica edfica. Las identificaciones mediante el uso de TRFLP slo detect un porcentaje de los taxones presentes en las muestras de suelo identificadas morfolgicamente, y los nematodos omnvoros y predadores no fueron detectados molecularmente en nuestro estudio. Los ndices calculados en base a los nematodos micrboros mostraron ms similitud cuando se identificaron morfolgica y molecularmente que los ndices basados en grupos trficos ms altos. Nuestros resultados muestran que, al menos con la tcnica usada en este estudio, la identificacin morfolgica de nematodos es una herramienta fiable y ms precisa que la identificacin molecular, puesto que en general se obtiene una mayor resolucin en la identificacin de nematodos. En el captulo 4, se estudiaron tambin los efectos de los nematicidas qumicos sobre la comunidad de nematodos y la biomasa de las plantas en condiciones experimentales de campo, donde se aplicaron en una rotacin de cultivo juda-col durante un ciclo de cultivo. Se aplicaron dos tipos de enmiendas orgnicas con el objetivo de mitigar el efecto negativo de los productos fitosanitarios sobre la diversidad edfica. El efecto de los nematicidas sobre las propiedades del suelo y sobre la comunidad de nematodos fue ms agudo que el efecto de las enmiendas. La incorporacin de los restos de cosecha al final del ciclo de cultivo de la juda tuvo un gran efecto sobre la comunidad de nematodos, y aunque el nmero total de nematodos increment al final del experimento, se observ una condicin perturbada permanente de la red trfica edfica a lo largo del experimento. ABSTRACT Due to the uncertain future of the soil fumigants most commonly used in the EU, that might involve risks for human/animal health and the environment, there is a need to develop new integrated pest management programs, included as mandatory in the Regulation (EC) No. 1107/2009, to control crop diseases. According to this Regulation, evaluating the risk associated to the use of the plant production products (PPP) on non-target soil fauna and their function, and developing assays with different indicator species to obtain toxicity data to be used in the risk evaluation is mandatory. However, the low representativeness of some of these indicator species in the Mediterranean area is a relevant limitation. In this situation, the Scientific Panel of Plant Protection Products and their Residues of the European Food Safety Authority (EFSA) has pointed out the necessity of modifying the ecotoxicological data set required to evaluate non-target effects of PPP in a more integrated way, including structural and functional endpoints with organism such as bacteria, fungi, protists and nematodes. Thus, EFSA has recommended the use of nematodes in the assessment of the functional and structural features of the soil. Nematodes are globally distributed and morphologically diverse, and due to their high abundance and diversity of responses to soil disturbance, they are suitable indicators of the soil condition. Since nematodes interact with many other organisms as participants in several links of the soil food web, playing important roles in essential soil processes in agroecosystems, nematode diversity is often used as a biological indicator of the effects of agricultural practices on soil condition. In the last years, various indices based on soil nematode assemblages, have facilitated the interpretation of complex soil ecological data. Soil food web indices based on the abundances of functional guilds defined by C-P groups and trophic groups, permit evaluating soil food web functioning. On the other hand, the difficulty of nematode taxonomical identification is commonly argued to explain their limited used as ecological indicators, and there is a certain controversy in terms of the efficacy of various nematode identification methods. It is argued that the morphological identification is difficult and time consuming due to the lack of specialist knowledge, and it is claimed that molecular techniques can solve some limitations of morphological techniques such as the identification of juveniles. Nevertheless, molecular identification methods are limited too, since most of the DNA-based databases are strongly oriented towards plant-parasitic nematodes that represent only a fraction of the soil nematode community, while there is little information available on free-living nematodes, which represent most soil nematodes. This work focuses on the study of the effects of soil fumigants on soil functioning through the use of different indicators based on soil nematode community as soil food web indices, diversity indices, the abundance of more relevant taxa etc. Other functional indicators related to soil suppressiveness, nutrient cycling, or the activity of soil microfauna have been also studied. In chapter 1, nematode diversity assessed in a commercial strawberry farm and its surroundings for two consecutive growing seasons in southern Spain, was low in fumigated soils with chemical pesticides throughout both seasons and, although yearly recovery occurred within the treated fields, fumigated soils showed a permanent perturbed condition. The nematode community was more closely associated to nutrient cycling in the non-cropped than in the cropped soils, and the link between plant biomass and nematode community structure was weak. Non-treated furrows within the treated fields were a reservoir of both beneficial and plant-parasitic nematodes, but such difference between furrows and beds was not enough to maintain more suppressive soil assemblages in the furrows. Treated soils were less suppressive than unmanaged soils, and there was a positive and significant correlation between soil suppressiveness and soil food web structure and diversity. In chapter 2, the effects of two organic pesticides with nematicide effect and two chemical nematicides on soil physicalchemical properties, soil nematode diversity and plant biomass in experimental conditions were assessed in two types of soils: low diversity soils from an agricultural farm, and high diversity soils from a natural vegetation area. The larger effect was observed on the neem treatment, which induced a large boost of dauer juveniles in the nutrient-depleted soil, while the same treatment induced the increase of more stable, less opportunistic, populations of generalist bacterivore nematodes in the pine forest soil, rich in organic matter. In chapter 3, comparison of the efficiency of molecular (TRFLP, Terminal Restriction Fragment Length Polymorphism) and morphological (microscopy at high magnification) identification methods was carried out in different nematode communities from five sites of different land uses in Spain and Ireland. Differences and similarities on nematode diversity and other ecological and soil food web indices assessed by both methods, were statistically compared. Molecular identification with TRFLP only detected a percentage of the taxa present in the soil samples identified morphologically, and omnivores and predators were not detected molecularly in our study. Indices involving microbial feeding nematodes were more similar between identification methods than indices involving higher trophic links. Our results show that, at least with the technique used in this study, identifying nematodes morphologically is a reliable and more precise identification tool than molecular identification, since a higher taxonomic resolution is in general obtained compared to TRFLP. In chapter 4, the effect of chemical nematicides on nematode community descriptors and plant biomass was also studied in field conditions in an experimental area in which dazomet and dimethyl disulfide was applied in a bean-cabbage rotation system for a single season. Organic amendments were incorporated into the soil with the aim of mitigate the negative effect of the pesticides on soil diversity. The effect of the nematicides was much more noticeable than the effect of the amendments on soil properties and nematode community descriptors. The incorporation of bean crop residues into the soil at the end of bean crop cycle affected soil nematode community descriptors to a great extent, and although total number of nematodes increased at the end of the experiment, a permanent perturbed soil food web condition was observed along the experiment.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Biochar is a carbon-rich solid obtained by the thermal decomposition of organic matter under a limited supply of oxygen and at relatively low temperatures. Biochar can be prepared from the pyrolysis of different organic feed- stocks, such as wood and biomass crops, agricultural by-products, different types of waste or paper industry waste materials . The pyrolysis procedure of waste, i.e. sewage sludge, has mainly two advantages, firstly, it removes pathogens from waste and, secondly, biochar can reduce the leaching of heavy metals present in raw sewage sludge. This trend of the use of waste material as feedstocks to the preparation of biochar is increasing in the last years due to industrial development and economic growth imply an increase in waste generation. The application of biochar may have positive effects on soil physical properties as water holding capacity and structure or on soil biological activity and soil quality. Also, biochar can be used to remove water pollutants and can be used in multiple ways in soil remediation due to its adsorption of pesticides or metals. Also, biochar contribute to carbon sequestration due to carbon stability of biochar materials. The objective of this presentation is to review the positive effects of the biochar prepared from organic waste on soil properties.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Ca-amendments are routinely applied to improve acid soils, whilst no-tillage (NT) has been widely recommended in soils where traditional tillage (TT) has led to losses of organic matter. However, the potential interactions between the two treatments are only partially known. Our study was conducted on an annual forage crop agrosystem with a degraded Palexerult soil located in SW Spain, in order to assess if the combination of NT plus a Ca-amendment provides additional benefits to those of their separate use. To this end we analysed the effects of four different combinations of tillage and Ca-amendment on selected key soil properties, focusing on their relationships. The experimental design was a split-plot with four replicates. The main factor was tillage (NT versus TT) and the second factor was the application or not of a Ca-amendment, consisting of a mixture of sugar foam (SF) and red gypsum (RG). Soil samples were collected from 3 soil layers down to 50 cm after four years of treatment (2009). The use of the Ca-amendment improved pH and Al-toxicity down to 25 cm and increased exchangeable Ca2+ down to 50 cm, even under NT due to the combined effect of SF and RG. Both NT and the Ca-amendment had a beneficial effect on total organic carbon (TOC), especially on particulate organic carbon (POC), in the 05 cm layer, with the highest contents observed when both practices were combined. Unlike NT, the Ca-amendment failed to improve soil aggregation in spite of the carbon supplied. This carbon was not protected within the stable aggregates in the medium term, making it more susceptible to mineralization. We suggest that the fraction of Al extracted by oxalate from solid phase (AlOxa-Cu-K) and the glomalin-related soil proteins (GRSPs) are involved in the accumulation of carbon within water stable aggregates, probably through the formation of non-toxic stable Al-OM compounds, including those formed with GRSPs. NT alone decreased AlK in the 05 cm soil layer, possibly by increasing POC, TOC and GRSPs, which were observed to play a role in reducing Al toxicity. From our findings, the combination of NT and Ca-amendment appears to be the best management practice to improve chemical and physical characteristics of acid soils degraded by tillage.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Aggregates provide physical microenvironments for microorganisms, the vital actors of soil systems, and thus play a major role as both, an arena and a product of soil carbon stabilization and dynamics. The surface of an aggregate is what enables exchange of the materials and air and water fluxes between aggregate exterior and interior regions. We made use of 3D images from X-ray CT of aggregates and mathematical morphology to provide an exhaustive quantitative description of soil aggregate morphology that includes both intra-aggregate pore space structure and aggregate surface features. First, the evolution of Minkowski functionals (i.e. volume, boundary surface, curvature and connectivity) for successive dilations of the solid part of aggregates was investigated to quantify its 3D geometrical features. Second, the inner pore space was considered as the object of interest. We devised procedures (a) to define the ends of the accessible pores that are connected to the aggregate surface and (b) to separate accessible and inaccessible porosity. Geometrical Minkowski functionals of the intra-aggregate pore space provide the exhaustive characterization of the inner structure of the aggregates. Aggregates collected from two different soil treatments were analyzed to explore the utility of these morphological tools in capturing the impact on their morphology of two different soil managements, i.e. conventional tillage management, and native succession vegetation treatment. The quantitative tools of mathematical morphology distinguished differences in patterns of aggregate structure associated to the different soil managements.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The spatial complexity of the distribution of organic matter, chemicals, nutrients, pollutants has been demonstrated to have multifractal nature (Kravchenco et al. [1]). This fact supports the possibility of existence of some emergent heterogeneity structure built under the evolution of the system. The aim of this note is providing a consistent explanation to the mentioned results via an extremely simple model.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Purpose The demand of rice by the increase in population in many countries has intensified the application of pesticides and the use of poor quality water to irrigate fields. The terrestrial environment is one compartment affected by these situations, where soil is working as a reservoir, retaining organic pollutants. Therefore, it is necessary to develop methods to determine insecticides in soil and monitor susceptible areas to be contaminated, applying adequate techniques to remediate them. Materials and methods This study investigates the occurrence of ten pyrethroid insecticides (PYs) and its spatio-temporal variance in soil at two different depths collected in two periods (before plow and during rice production), in a paddy field area located in the Mediterranean coast. Pyrethroids were quantified using gas chromatography?mass spectrometry (GC?MS) after ultrasound-assisted extraction with ethyl acetate. The results obtained were assessed statistically using non-parametric methods, and significant statistical differences (p < 0.05) in pyrethroids content with soil depth and proximity to wastewater treatment plants were evaluated. Moreover, a geographic information system (GIS) was used to monitor the occurrence of PYs in paddy fields and detect risk areas. Results and discussion Pyrethroids were detected at concentrations ?57.0 ng g?1 before plow and ?62.3 ng g?1 during rice production, being resmethrin and cyfluthrin the compounds found at higher concentrations in soil. Pyrethroids were detected mainly at the top soil, and a GIS program was used to depict the obtained results, showing that effluents from wastewater treatment plants (WWTPs) were the main sources of soil contamination. No toxic effects were expected to soil organisms, but it is of concern that PYs may affect aquatic organisms, which represents the worst case scenario. Conclusions A methodology to determine pyrethroids in soil was developed to monitor a paddy field area. The use of water fromWWTPs to irrigate rice fields is one of the main pollution sources of pyrethroids. It is a matter of concern that PYs may present toxic effects on aquatic organisms, as they can be desorbed from soil. Phytoremediation may play an important role in this area, reducing the possible risk associated to PYs levels in soil.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Recent improvements in our understanding of the dynamics of soil carbon have shown that 2040% of the approximately 1,500 Pg of C stored as organic matter in the upper meter of soils has turnover times of centuries or less. This fast-cycling organic matter is largely comprised of undecomposed plant material and hydrolyzable components associated with mineral surfaces. Turnover times of fast-cycling carbon vary with climate and vegetation, and range from <20 years at low latitudes to >60 years at high latitudes. The amount and turnover time of C in passive soil carbon pools (organic matter strongly stabilized on mineral surfaces with turnover times of millennia and longer) depend on factors like soil maturity and mineralogy, which, in turn, reflect long-term climate conditions. Transient sources or sinks in terrestrial carbon pools result from the time lag between photosynthetic uptake of CO2 by plants and the subsequent return of C to the atmosphere through plant, heterotrophic, and microbial respiration. Differential responses of primary production and respiration to climate change or ecosystem fertilization have the potential to cause significant interrannual to decadal imbalances in terrestrial C storage and release. Rates of carbon storage and release in recently disturbed ecosystems can be much larger than rates in more mature ecosystems. Changes in disturbance frequency and regime resulting from future climate change may be more important than equilibrium responses in determining the carbon balance of terrestrial ecosystems.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

A tomato gene that is induced early after infection of tomato (Lycopersicon esculentum Mill.) with root-knot nematodes (Meloidogyne javanica) encodes a protein with 54% amino acid identity to miraculin, a flavorless protein that causes sour substances to be perceived as sweet. This gene was therefore named LeMir (L. esculentum miraculin). Sequence similarity places the encoded protein in the soybean trypsin-inhibitor family (Kunitz). LeMir mRNA is found in root, hypocotyl, and flower tissues, with the highest expression in the root. Rapid induction of expression upon nematode infection is localized to root tips. In situ hybridization shows that LeMir is expressed constitutively in the root-cap and root-tip epidermis. The LeMir protein product (LeMir) was produced in the yeast Pichia pastoris for generation of antibodies. Western-blot analysis showed that LeMir expression is up-regulated by nematode infection and by wounding. LeMir is also expressed in tomato callus tissue. Immunoprint analysis revealed that LeMir is expressed throughout the seedling root, but that levels are highest at the root/shoot junction. Analysis of seedling root exudates revealed that LeMir is secreted from the root into the surrounding environment, suggesting that it may interact with soil-borne microorganisms.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The Podzols of the world are divided into intra-zonal and zonal according to then location. Zonal Podzols are typical for boreal and taiga zone associated to climate conditions. Intra-zonal podzols are not necessarily limited by climate and are typical for mineral poor substrates. The Intra-zonal Podzols of the Brazilian Amazon cover important surfaces of the upper Amazon basin. Their formation is attributed to perched groundwater associated to organic matter and metals accumulations in reducing/acidic environments. Podzols have a great capacity of storing important amounts of soil organic carbon in deep thick spodic horizons (Bh), in soil depths ranging from 1.5 to 5m. Previous research concerning the soil carbon stock in Amazon soils have not taken into account the deep carbon stock (below 1 m soil depth) of Podzols. Given this, the main goal of this research was to quantify and to map the soil organic carbon stock in the region of Rio Negro basin, considering the carbon stored in the first soil meter as well as the carbon stored in deep soil horizons up to 3m. The amount of soil organic carbon stored in soils of Rio Negro basin was evaluated in different map scales, from local surveys, to the scale of the basin. High spatial and spectral resolution remote sensing images were necessary in order to map the soil types of the studied areas and to estimate the soil carbon stock in local and regional scale. Therefore, a multi-sensor analysis was applied with the aim of generating a series of biophysical attributes that can be indirectly related to lateral variation of soil types. The soil organic carbon stock was also estimated for the area of the Brazilian portion of the Rio Negro basin, based on geostatistical analysis (multiple regression kriging), remote sensing images and legacy data. We observed that Podzols store an average carbon stock of 18 kg C m-2 on the first soil meter. Similar amount was observed in adjacent soils (mainly Ferralsols and Acrisols) with an average carbon stock of 15 kg C m-2. However if we take into account a 3 m soil depth, the amount of carbon stored in Podzols is significantly higher with values ranging from 55 kg C m-2 to 82 kg C m-2, which is higher than the one stored in adjacent soils (18 kg C m-2 to 25 kg C m-2). Given this, the amount of carbon stored in deep soil horizons of Podzols should be considered as an important carbon reservoir, face a scenario of global climate change

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Determination of reliable solute transport parameters is an essential aspect for the characterization of the mechanisms and processes involved in solute transport (e.g., pesticides, fertilizers, contaminants) through the unsaturated zone. A rapid inexpensive method to estimate the dispersivity parameter at the field scale is presented herein. It is based on the quantification by the X-ray fluorescence solid-state technique of total bromine in soil, along with an inverse numerical modeling approach. The results show that this methodology is a good alternative to the classic Br determination in soil water by ion chromatography. A good agreement between the observed and simulated total soil Br is reported. The results highlight the potential applicability of both combined techniques to infer readily solute transport parameters under field conditions.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Nathaniel Freeman made entries in this commonplace book between 1786 and 1787, while he was an undergraduate at Harvard College. The book includes the notes Freeman took during three of Hollis Professor Samuel Williams' "Course of Experimental Lectures," and cover Williams' lectures on "The Nature & Properties of Matter," "Attraction & Repulsion," and "The Nature, Kind, & Affections [?] of Motion." These notes also include one diagram. The book also includes forensic compositions on the subjects of capital punishment, the probability of "the immortality of the soul," and "whether there be any disinterested benevolence." It also includes a poem Freeman composed for his uncle, Edmund Freeman; an anecdote about Philojocus and Gripus; an essay called "Character"; a draft of a letter to the Harvard Corporation requesting that, in light of the public debt, the Commencement ceremonies be held privately to lower expenses and exhibit the merits of economy; and an "epistle" to his father, requesting money. This epistle begins: "Most honored sire, / Thy son, poor Nat, in humble strains, / Impell'd by want, thy generous bounty claims."

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This layer is a georeferenced raster image of the historic, paper map entitled: Survey of the Cape of Good Hope, by Lieut. A.T.E. Vidal of H.M.S. Leven, assisted by Captn. Chas. Lechmere, R.N. Lieut T. Boteler, and Mr. H.A. Gibbons, Admlty. Midn. under the direction of Captn. W.F.W. Owen, 1822. J. & C. Walker sculpt. It was published according to Act of Parliament at the Hydrographical Office of the Admiralty, 4th March 1828. Scale [ca. 1:153,512]. Covers the Cape Peninsula region, including False Bay and Cape Town, South Africa. The image inside the map neatline is georeferenced to the surface of the earth and fit to the 'WGS 1984 UTM 34S' coordinate system. All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. This map shows coastal features such as beacons, rocks, channels, points, coves, islands, bottom soil types, anchorage points, and more. Includes also selected land features such as roads, drainage, land cover, selected buildings, towns, and more. Relief shown by contours; depths by soundings. Includes notes, table of heights, and two views. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Tese de mestrado integrado em Engenharia da Energia e do Ambiente, apresentada Universidade de Lisboa, atravs da Faculdade de Cincias, 2016

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Introduction The strong expansion of the world production of plastics caused a severe accumulation of plastic debris in the environment, which makes them one of the most important contaminants, growing as a global environmental problem. Although the production in Europe has been relatively constant in the last 10 years, world plastic production continues to increase, affecting soil biota and their functions. Objectives Thus, in order to evaluate the effects of MP in soil-dwelling organisms, earthworms (Eisenia andrei Bouch), were exposed to standard artificial soil mixed with MPs and the authors documented, using microscopic figures, the pathological lesions found in this biological model. Material and Methods Eight adult earthworms extracted from soils contaminated with different concentrations of MP (mg/kgdw) with sizes ranging between 250-1000 m, were fixed in 10% neutral-buffered formalin and processed for routine histopathological diagnosis. Results and discussion Contrary to what would be expected, MP were not found throughout the GI tube of earthworms but several lesions were found in the individuals extracted from the soils with high MP concentrations, when compared with control group, namely epithelial intestinal atrophy and evidences of inflammatory responses to this stress agent. Conclusion Earthworms have probably avoided the consumption of the biggest MPs. However, evidences point for lesions that were likely caused by the smallest MPs that were likely egested during the depuration phase.