1,721,022 research outputs found
Impacto de agroquímicos sobre la contaminación de suelos y aguas
No full textPresentación de diapositivasEl glifosato es uno de los plaguicidas más utilizados en todo el mundo. El aumento del uso de glifosato a nivel mundial, desde finales de la década de 1990, fue impulsado por la adopción de cultivos genéticamente modificados. El uso promedio de herbicidas por hectárea aumentó constantemente desde mediados de los años noventa. La frecuencia de aparición y los niveles de glifosato están aumentando en una variedad de alimentos (Benbrook, 2016).EEA BalcarceFil: Costa, Jose Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentin
Plaguicidas en el ambiente
Full text linkPlaguicidas en el Ambiente es un documento que surge como iniciativa del Proyecto Nacional de Suelo (PNSuelo-INTA) 1134044: “Destino ambiental y degradación de los plaguicidas agregados al suelo”, para poner a disposición de los profesionales interesados el estado del arte de la problemática del uso de los plaguicidas en la Argentina.Fil: Aparicio, Virginia Carolina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Costa, Jose Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Gonzalo Mayoral, Eliana Soledad. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentin
Quality assessment of irrigation water under a combination of rain and irrigation
No full textSupplementary irrigation is one of the proposed management practices to increase the area under grain production mainly in the Humid Pampas (HP). The most common source of irrigation water in the HP comes from groundwater and is characterized by its high sodium bicarbonate content. However, the effect of the combination of irrigation and rain water on the chemical and physical properties of soils, especially when irrigation water comprises water with sodium bicarbonate, is still not well documented. The objective of the present study is to establish irrigation water suitability criteria under conditions of combined rain and irrigation. The trials were carried out on six irrigated plots and another five plots were chosen for validation purposes. Hydraulic conductivity and bulk density were measured in the field. Soil chemical analysis was performed on undisturbed soil samples. Supplementary irrigation using sodium bicarbonated water raises the soil electrical conductivity (ECe), the pH, exchangeable sodium percentage (ESP), soil sodium adsorption ratio (SARe) and cation exchange capacity (CEC) which produces an increase in bulk density (δb), reducing the overall porosity of the soil. The effect of the soil SAR on the soil hydraulic conductivity (K) was evident when the soil SAR levels were greater than 3.5. The dilution factor proposed in this study allows the classification of water for supplementary irrigation linked to the management of irrigation.EEA BalcarceFil: Costa, Jose Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Aparicio, Virginia Carolina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentin
Glyphosate Dissipation in Different Soils under No-Till and Conventional Tillage
Full text linkGlyphosate is the most used herbicide in Argentina, accounting for 62% of the commercialized pesticides in the market. It is used as a weed controller in no-till systems, and it is also applied in various genetically modified crops (e.g. soybean, corn, cotton). Though it has a high solubility in water, it tends to adsorb and accumulate in agricultural soils. The main objectives of this work were to compare the dissipation of glyphosate and the accumulation of its metabolite aminomethylphosphonic acid (AMPA) over time in three soils from agricultural areas of Argentina, under long-term management of no-till (NT) and conventional tillage (CT) practices. Forty percent of the applied glyphosate was degraded within the first three days in all soils, indicating a fast initial dissipation rate. However, the dissipation rate considerably decreased over time and the degradation kinetics followed a two-compartment kinetic model. No differences were found between tillage practices. Dissipation was not related to the microbial activity measured as soil respiration. The fast decrease in the concentration of glyphosate at the beginning of the dissipation study was not reflected in an increase on the concentration of AMPA. The estimated half-lives for glyphosate ranged between 9 and 38 days. However, glyphosate bioavailability decreases over time as it is strongly adsorbed to the soil matrix. This increases its residence time which may lead to its accumulation in agricultural soils.Fil: Okada, Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Costa, Jose Luis. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Bedmar, Francisco. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias. Departamento de Producción Vegetal; Argentin
Delineation of management zones with soil apparent electrical conductivity to improve nutrient management
Full text linkSite-specific management demands the identification of subfield regions with homogeneous characteristics (management zones). However, determining subfield areas is difficult because of complex correlations and the spatial variability of soil properties and nutrient concentrations, responsible for variations in crop yields within the field. We evaluated whether apparent electrical conductivity (ECa) is a potential estimator of soil properties and nutrients, and a tool for the delimitation of homogeneous zones. Two field sites with several soil series were studied in southeastern Cordoba Province, Argentina. Soil properties and nutrient concentrations were compared with ECa using principal components (PC)- stepwise regression and ANOVA. The PC-stepwise regression showed that soil properties (pH, EC1:2.5, CEC, SOM) and nutrients (Na+2, Mg+2, Mn+2, Cu+2, Ca+2, Zn+2, Fe+2) are key loading factors to explain the ECa (R2>0.90). In contrast, K+, P, NO3--N and SO4-2-S), content were not able to explain the ECa. The ANOVA showed that ECa measurements successfully delimited two homogeneous soil zones associated with the spatial distribution of soil properties and some nutrients (Na+2, Mg+2, Mn+2, Cu+2, Ca+2, Zn+2, Fe+2). These results suggest that field-scale ECa maps have the potential to design sampling zones to implement site-specific management strategies.Fil: Peralta, Nahuel Raúl. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires. Estación Experimental Agropecuaria Balcarce. Area de Investigación en Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Costa, Jose Luis. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires. Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin
Adsorption and mobility of glyphosate in different soils under no-till and conventional tillage
Full text linkGlyphosate (N-(phosphonomethyl) glycine) is a post-emergence, non-selective, foliar herbicide. Around 200 million. liters of this herbicide are applied every year in Argentina, where the main agricultural practice is no-till (NT), accounting for 78.5% of the cultivated land. In this work, we studied the adsorption of glyphosate in different soils under long-term management (more than 16 years) of NT and conventional tillage (CT). Samples were taken from different regions of Argentina corresponding to: Paraná soil (PAR), a silty clay loam soil (< 37% clay), Manfredi (MAN) and Pergamino (PER), both silty loam soils (< 26% clay). We found that the adsorption was very high in all the soils, and it was particularly influenced by the soil clay content and CEC and negatively related to pH and phosphorus. In general, the adsorption coefficient (Kf) was higher in the CT samples. We also studied the vertical transport of glyphosate in undisturbed columns (15 cm long) and compared the effect of NT and CT. Less than 0.24% of the applied pesticide leached in all soils. No significant difference was found between the total amount of leached glyphosate between soils or tillage practice. The highest glyphosate concentration (67.53% of the initially applied doses) was found in the top 5 cm of the columns. The strong retention of glyphosate to the soil matrix, as confirmed by the high Kf values obtained in the isotherm studies, was the dominant factor influencing glyphosate mobility through the soil profile.Fil: Okada, Elena. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Costa, Jose Luis. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Bedmar, Francisco. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Interpretación de la conductividad eléctrica aparente para la delimitación de zonas de manejo en el sudeste bonaerense
Full text linkLa variabilidad espacial de la conductividad Eléctrica Aparente (CEa) esta asociada con propiedades físicas del suelo (textura y humedad del suelo). Esta investigación tuvo como objetivo determinar la utilidad de los mapas de CEa para delimitar zonas de manejo homogéneas. Para esto se midió la CEa con el Veris 3100, estableciendo su relación espacial con las propiedades físicas del suelo en dos lotes de producción ubicados en el partido de Lobería (Fernandez) y Azul (Huesos) de la Provincia de Buenos Aires. Se realizó un análisis exploratorio de datos, un análisis de correlación de Pearson y finalmente un ANOVA entre las zonas potenciales de manejo. La medicion geo-espacial de la CEa estuvo correlacionada positivamente con el contenido de arcilla y humedad del suelo, y negativamente con el contenido de arena y permitió delimitar significativamente (p<0.05) zonas potenciales de manejo. De acuerdo con los resultados se concluye que los mapas de CEa son una fuente confiable de datos para explicar la variabilidad espacial de las propiedades físicas y delimitar zonas potenciales de manejo, brindando la posibilidad de aplicar manejo sitio-específico.Fil: Peralta, Nahuel Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Costa, Jose Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; ArgentinaFil: Castro Franco, Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin
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