1,721,105 research outputs found
Soil preference and burrow structure of an endangered tarantula, Brachypelma vagans (Mygalomorphae: Theraphosidae)
No full textM, Salima Machkour, Rabet, Hénaut, Yann, Sepúlveda, Alejandra, Rojo, Roberto, Calmé, Sophie, Geissen, Violette (2007): Soil preference and burrow structure of an endangered tarantula, Brachypelma vagans (Mygalomorphae: Theraphosidae). Journal of Natural History 41 (17-20): 1025-1033, DOI: 10.1080/00222930701384547, URL: http://dx.doi.org/10.1080/0022293070138454
Figure 2. Principal components 1 and 2 in Soil preference and burrow structure of an endangered tarantula, Brachypelma vagans (Mygalomorphae: Theraphosidae)
No full textFigure 2. Principal components 1 and 2 extracted from the analysis of the tarantula densities and soil characteristics (squares) at seven sites (circles). See ''Methods'' for codes.Published as part of M, Salima Machkour, Rabet, Hénaut, Yann, Sepúlveda, Alejandra, Rojo, Roberto, Calmé, Sophie & Geissen, Violette, 2007, Soil preference and burrow structure of an endangered tarantula, Brachypelma vagans (Mygalomorphae: Theraphosidae), pp. 1025-1033 in Journal of Natural History 41 (17-20) on page 1029, DOI: 10.1080/00222930701384547, http://zenodo.org/record/522879
Wind erosion processes and related glyphosate transport in the loess pampean region of Córdoba province, Argentina
Full text linkFil: Bento, Célia P. M. Wageningen University. Soil Physics and Land Management; Países Bajos.Fil: Geissen, Violette. Wageningen University. Soil Physics and Land Management; Países Bajos.Fil: Riksen, Michel. Wageningen University. Soil Physics and Land Management; Países Bajos.Fil: Mol, Hans. Wageningen University. Research Centre. RIKILT Institute of Food Safety; Países Bajos.Fil: Murialdo, Raquel. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales; Argentina.Fil: Ritsema, Coen. Wageningen University. Soil Physics and Land Management; Países Bajos.Fil: Reyna, Santiago. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales; Argentina.The results of this experiment will provide: Insight on glyphosate and AMPA concentrations in wind-eroded sediment; Valuable information on the losses of glyphosate and AMPA to off-site environments due to wind erosion; A strong contribution to the Argentinean decision makers, stakeholders and the international community in the knowledge of glyphosate/AMPA transport by wind erosion, and its potential impact to the environment and human health.Fil: Bento, Célia P. M. Wageningen University. Soil Physics and Land Management; Países Bajos.Fil: Geissen, Violette. Wageningen University. Soil Physics and Land Management; Países Bajos.Fil: Riksen, Michel. Wageningen University. Soil Physics and Land Management; Países Bajos.Fil: Mol, Hans. Wageningen University. Research Centre. RIKILT Institute of Food Safety; Países Bajos.Fil: Murialdo, Raquel. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales; Argentina.Fil: Ritsema, Coen. Wageningen University. Soil Physics and Land Management; Países Bajos.Fil: Reyna, Santiago. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales; Argentina.Otras Ingeniería del Medio Ambient
Figure 3 in Soil preference and burrow structure of an endangered tarantula, Brachypelma vagans (Mygalomorphae: Theraphosidae)
No full textFigure 3. Structures of the burrows of Brachypelma vagans. (A) Burrow with four chambers; (B) burrow with two chambers; (C) prototype of single chamber burrow; (D) prototype of burrow without chamber. a, Entrance diameter of the burrow; b, length of the tunnel; c, depth of the burrow; d1–d4, length of chambers; e1–e4, width of chambers; f1–f4, height of chambers.Published as part of M, Salima Machkour, Rabet, Hénaut, Yann, Sepúlveda, Alejandra, Rojo, Roberto, Calmé, Sophie & Geissen, Violette, 2007, Soil preference and burrow structure of an endangered tarantula, Brachypelma vagans (Mygalomorphae: Theraphosidae), pp. 1025-1033 in Journal of Natural History 41 (17-20) on page 1030, DOI: 10.1080/00222930701384547, http://zenodo.org/record/522879
FTIR hyperspectral image of microplastics extracted from a soil sample
No full textGeneral description
The upload presents an uFTIR hyperspectral image of microplastics extracted form a soil sample taken with an Agilent Cary 620 FTIR spectrometer. The image was used to perform the benchmark test of an R package: uFTIR (https://CRAN.R-project.org/package=uFTIR).
Microplastic extraction
The sample comes from a previous study (Corradini et al, 2019) from which we take a sample testing 1.4 plastics particles per gram of soil by Zhang et al (2018) method reported in (Corradini et al, 2021a). The soil sample was suspended in ZnCl2, stirred, centrifuged, and vacuum-filtered three times. At the end of the preparation process, a filter (Whatman(R) Anodisc Inorganic Membranes) that collected all buoyant particles was ready for the image acquisition.
Image acquisition
The FTIR analysis was performed in transmission mode with a spectral resolution of 8 cm-1 through a spectral range of 3500 - 1300 cm-1 and 8 co-added scans. Data was recorded in absorbance (%). The microscope magnification was x4 with a pixel size resolution of 20.6 m. The image comprises 64 single shots and 12Gb.
Accompanying data
We included a second folder that holds 4 images of 4 films made of 4 different plastic polymers that we took under the same conditions. We used this data to validate the accuracy of the software. The polymer films correspond to one polyethylene bag, two plastic cups ---one made of polypropylene and the other made of polystyrene---, and a polystyrene standard film (VARIAN P/N 883-9120).
Further reading
For a closer description of the soil sample and sample preparation see Corradini et al (2021a). For a detailed description of the software see (Corradini et al, 2021b), and visit the CodeOcean computer capsule at https://doi.org/10.24433/CO.5579643.v1. The software itself is available at R-CRAN repository (https://CRAN.R-project.org/package=uFTIR).
If you reuse this image please cite
Corradini, F, N Berriot, E Huerta-Lwanga, V Geissen. 2021. uFTIR: an R package to process hyperspectral images of environmental samples captured with FTIR microscopes. SoftwareX,
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References
Corradini et al. 2021a. 2021. Microplastics occurrence and frequency in soils under different land uses on a regional scale. Science of the Total Environment, 752, 141917. 10.1016/j.scitotenv.2020.141917
Corradini et al. 2021b. uFTIR: an R package to process hyperspectral images of environmental samples captured with FTIR microscopes. SoftwareX, 16, 100857. 10.1016/j.softx.2021.100857
Corradini et al. 2019. Usefulness of an opportunistic data analysis approach to evaluate if environmental regulations aim at relevant applications. Geoderma, 351, 261-269. 10.1016/j.geoderma.2019.05.007
Zhang et al. 2018. A simple method for the extraction and identification of light density microplastics from soil. Science of the Total Environment, 616-617, 1056-1065. 10.1016/j.scitotenv.2017.10.213This work was supported by Comisión Nacional de Investigación Cientı́fica y Tecnológica, CONICYT [grant 72170044
Impacts of agricultural management practices on soil quality in Europe and China - insights from the EU iSQAPER project
Full text linkPlastic mulch and pesticides residues in intensive agriculture
Full text link[SPA] En la década de 1960, la “revolución verde” agrícola trajo nuevas tecnologías y una gran mecanización en los campos. Estas tecnologías aportaron respuestas rápidas para aumentar los rendimientos de los cultivos y mejorar la seguridad alimentaria. En estas tecnologías encontramos aplicaciones de pesticidas y de acolchado plástico. Desde entonces, la comunidad científica y el público en general se preocuparon por las consecuencias de estas soluciones a corto plazo. De hecho, el acolchado plástico y los pesticidas dejan residuos que se acumulan en el suelo y son potencialmente peligrosos para algunos organismos. Con esta tesis doctoral tratamos de describir el riesgo de la acumulación de residuos de plástico y de pesticidas en agricultura. Este trabajo está organizado en siete capítulos que se describen a continuación. En la introducción, presentamos los varios beneficios del uso de pesticidas y plásticos en agricultura. Los muchos servicios que ofrecen explican por qué se usan abundantemente en todo el mundo. Sin embargo, tanto el plástico como los pesticidas tienen el potencial de acumularse en el suelo. Con respecto a el plástico, hicimos la diferencia entre fuentes directas (p. ej., acolchado plástico, fertilizantes recubiertos con plástico) e indirectas (p. ej., lodos de depuradora, compost). Explicamos los procesos de degradación de los residuos plásticos en microplásticos y, al final, en agua y CO2. Diferenciamos entre microplásticos primarios (~prístinos) y secundarios (~degradados). Nos focalizamos en el uso de acolchado plástico, ya que se usa abundantemente en todo el mundo y que se reconozca como una fuente importante de desechos plásticos. Presentamos tres tipos de plástico diferentes: Polietileno de baja densidad (LDPE), acolchados que contienen aditivos prooxidantes (PAC) y biodegradables (BIO). Finalmente, presentamos las amenazas que representan los residuos de plástico y pesticidas y la necesidad de más investigación. Elaboramos seis preguntas principales que se abordan en los siguientes cinco capítulos de investigación. El objetivo de esta evaluación de campo fue medir los residuos de plásticos y pesticidas en los suelos agrícolas y sus efectos en el microbioma del suelo. Para eso, tomamos muestras de suelo (0-10 cm y 10-20 cm) de 18 parcelas de 6 huertas del sureste de España. Las fincas estaban bajo manejo orgánico o convencional, donde se había usado acolchado plástico por más de 25 años. Medimos el contenido de desechos plásticos de densidad micro y macro, los niveles de residuos de pesticidas y una variedad de propiedades fisicoquímicas. También llevamos a cabo la secuenciación del ADN de las comunidades fúngicas y bacterianas del suelo. Se encontraron residuos plásticos en todas las muestras y se encontraron de 4 a 10 residuos de pesticidas diferentes en todos los suelos en manejo convencional. En general, el contenido de pesticidas fue ~100 veces menor en manejo orgánico, mientras que no se observaron diferencias significativas en el contenido de plástico entre manejos. Las comunidades fúngicas y bacterianas eran específicas de cada finca y estaban relacionadas con diferentes parámetros fisicoquímicos y contenido de contaminantes en el suelo. En cuanto a los contaminantes, las comunidades bacterianas respondieron al total de residuos de pesticidas, al fungicida Azoxystrobin y al insecticida Clorantraniliprol, así como al total del área de plástico. El fungicida Boscalid fue el único contaminante que influyó en la comunidad fúngica. Demostramos que los residuos de plástico y pesticidas estaban presentes juntos en el suelo, por lo que nos preguntamos hasta qué punto podría haber absorción de pesticidas en los residuos plásticos. El objetivo de esta investigación fue de medir la sorción de las sustancias activas de los pesticidas en acolchados de LDPE, PAC y BIO plástico y comparar la descomposición de las sustancias activas en presencia y ausencia de desechos plásticos. Para eso, se incubaron 38 sustancias activas de 17 insecticidas, 15 fungicidas y seis herbicidas comúnmente aplicados con acolchado plástico en el sureste de España con una pieza de acolchado plástico de 3 × 3 cm2 (LDPE, PAC y Bio). La incubación se realizó en una solución de 10% acetonitrilo y 90% agua destilada a 35 °C durante 15 días en oscuridad. La sorción dependió tanto del pesticida como del tipo de acolchado plástico. En promedio, el porcentaje de sorción fue de ~23 % en LDPE y PAC y ~50 % en BIO. La descomposición de las sustancias activas en presencia de plástico fue ~30 % menor que la descomposición de las sustancias activas en solución sola. Investigamos si los residuos plásticos encontrados en el suelo en el capítulo 2 podrían modificar las propiedades fisicoquímicas del suelo. Probamos el impacto de residuos plásticos de tamaño macro (~5 mm) y micro ( 25 years. We measured the macro and micro light density plastic debris content, the pesticide residue levels, and a range of physiochemical properties. We also carried out DNA sequencing on the soil fungal and bacterial communities. Plastic debris was found in all samples and 4-10 different pesticide residues were also found in all conventional soils. Overall, pesticide content was ~100 times lower in organic farms, whereas no significant difference in plastic content was observed between organic and conventional farms. The fungal and bacterial communities were farm-specific and related to different soil physicochemical parameters and contaminants. Regarding contaminants, bacterial communities responded to the total pesticide residues, the fungicide Azoxystrobin and the insecticide Chlorantraniliprole as well as the total plastic area. The fungicide Boscalid was the only contaminant to influence the fungal community. We proved that plastic and pesticide residues were present together in the soil so we wondered to which extend there could be sorption of pesticides on plastic debris. The aim of this research was to measure the sorption pattern of active substances from pesticides on LDPE, PAC and Bio plastic mulches and to compare the decay of the active substances in the presence and absence of plastic debris. For this purpose, 38 active substances from 17 insecticides, 15 fungicides and six herbicides commonly applied with plastic mulching in South-east Spain were incubated with a 3 × 3 cm2 piece of plastic mulch (LDPE, PAC and Bio). The incubation was done in a solution of 10% acetonitrile and 90% distilled water at 35 °C for 15 days in the dark. The sorption behaviour depended on both the pesticide and the plastic mulch type. On average, the sorption percentage was ~23% on LDPE and PAC and ~50% on Bio. The decay of active substances in the presence of plastic was ~30% lesser than the decay of active substances in solution alone. We investigated whether the plastic debris found in the soil in chapter 2 could modify the soil physicochemical properties. We tested the impact of macro (around 5 mm) and micro (< 1 mm) sized plastic debris from LDPE and one type of starch-based Bio mulch film on soil physicochemical and hydrological properties. The bulk density, porosity, saturated hydraulic conductivity, field capacity and soil water repellency were altered significantly in the presence of the four kinds of plastic debris, while pH, electrical conductivity and aggregate stability were not substantially affected. The type, size and content of plastic debris as well as the interactions between these three factors played complex roles in the variations of the measured soil parameters. We expanded the focus of our work from the soil to living being walking on it by investigating the question: Do sheep ingest the plastic debris when they are grazing in contaminated fields? To give an answer, we collected sheep faeces from 5 different herds and analysed the light density microplastic content. We found ~103 particles∙kg-1 in the faeces. The data showed that livestock ingested plastic, in the form of microplastics and/or macroplastics. Further studies should focus on: assessing how much of the plastic found in faeces is coming directly from plastic mulching, estimating the plastic degradation in the guts of sheep and understanding the potential effects of these plastic residues on the health of livestock. In a final mesocosm experiment, we replicated field conditions to test if plastic mulch and pesticide residues could affect the plant production. We tested three plastic mulches and three pesticides commonly used by farmers. Low density polyethylene (LDPE), Pro-oxidant Additive Containing (PAC) and biodegradable (BIO) mulches were laid in a field for four months, shredded into micro- and macro- plastics and added to the soil with pesticides. Plastic and pesticides were left in the mesocosm to incubate for a year in field condition before lettuces seedlings, Lactuca sativa, were planted. After 14 weeks growing periode, we measured the basal diameter, number of leaves, leaf area, fresh shoot biomass, dry shoot biomass and shoot water content. We observed a decreased leaf area, fresh shoot biomass and dry shoot biomass in plants growing in soil where BIO plastic was present compared to the control. These results add up to previous studies in a call for more detailed test before approval of BIO mulches for agriculture on the market. The main findings of the thesis were summarized in the last chapter. We compared our results with existing literature and discussed the links between the chapters. We explored the limitations of current plastic and pesticide residues detection. More specifically, the detection of small plastic debris, microplastics and nanoplastics, in soil remains a challenge and a diversity of methods are being developed. We suggested that the diversity of methods is required to describe the diversity of plastic types, sizes and shapes and the methods need to be adapted to the specific objective of the study. We also discussed the current levels of plastic and pesticides residues in soil and which concentrations should be used to assess their potential impacts. Finally we explored different options to control the impacts of plastic and pesticides residues in agriculture. No ‘one-fits-all’ approach can be suggested as agricultural systems are very diverse and face many challenges. Nevertheless best practices are recommended to limit the accumulation of residues in the environment: use stronger plastic mulch for a more efficient removal and recycling or use biodegradable plastic tested in field conditions; be mindful of the climate conditions when applying pesticides and take into account their specific residence time in soil. We conclude that plastic and pesticides use are artificial inputs which affect natural processes in some detrimental manner while many natural processes are beneficial to crop production. We need more investigation and initiatives to tailor agricultural management to their specific conditions and challenges.Escuela Internacional de Doctorado de la Universidad Politécnica de CartagenaPrograma de doctorado en Tecnología y Modelización en Ingeniería Civil, Minera y AmbientalUniversidad Politécnica de Cartagen
Evaluación del efecto de la incorporación de dos tipos de plásticos (biodegradable y convencional) y la actividad de lombrices en suelos arenosos en trigo (Triticum aestivum L.)
No full text38 p.Películas plásticas como polietileno de baja densidad (PEBD) y biodegradables en la agricultura surgen como alternativa para la protección del suelo, cultivo y agua. El conocimiento de estos plásticos en el ecosistema terrestre es escaso. Los objetivos fueron evaluar en el desarrollo de las plantas de trigo: i. El efecto de la incorporación de plástico biodegradable y convencional en suelos arenosos, ii. El efecto del tamaño de los macro y micro plásticos y iii. El efecto de las lombrices (Lumbricus terrestris). El estudio se realizó en una cámara climatizada en la Universidad Wageningen, Holanda. Se usaron dos películas plásticas, dos tamaños de partículas (5 – 10 mm y <1 mm), presencia y ausencia de lombrices, en un diseño DCA y cinco repeticiones (P ≤0.05). Se evaluaron en plantas semanalmente altura y número de hojas y al corte diámetro de tallo, biomasa aérea y radicular, hojas vivas y muertas, área foliar y macollamiento, pH y conductividad del suelo y mortalidad y peso de lombrices. La incorporación del plástico biodegradable en una concentración de 1% p/p en suelo retarda el desarrollo del trigo, baja la conductividad eléctrica en el suelo y no afecta el pH, mientras que el PEBD en el suelo no causa efecto en crecimiento pero genera mayor área foliar. Los micro plásticos retrasan el crecimiento del trigo. Las lombrices bajaron el pH del suelo, incrementaron la biomasa, el número de hojas, macollamiento y área foliar pero no tuvieron efecto en la altura y diámetro del tallo; su mortalidad incrementa en presencia de plástico biodegradable
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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