819 resultados para Herbicidas - Biodegradação
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In 2001, it was estimated that pesticide used worldwide exceeded 2.27 billion kilograms, over 35%, of which, were herbicides. Brazil is considered one of the leaders in the production of sugarcane and mainly ethanol as fuel. The monoculture of sugarcane requires the usage of a range of pesticides, among these, the herbicides diuron and tebuthiuron. The degradation products most studied (DCA and DCPU) are diuron's, especially for toxicological characteristics of this herbicide that is identified as carcinogen and suspected to be endocrine disruptor in mammals. After optimization of the chromatographic separation using HPLC-UV, the analytical curve was constructed in solvent and subsequently in the matrix (surface water). The extraction method contains the usage of SPE (solid phase extraction) (Strata-X, 200 mg/6 mL), applicating 1L of sample and elution with 5 mL of acetonitrile / methanol (50:50, v/v). Analysis by HPLC/UV was performed in gradient mode, acetonitrile/water (70/30-74/26 by 1 min, 74/26 - 78/22 till 3.2 min, returning to initial conditions and remaining this way until 10 min), 018 column (Phenomenex, 4.6 mm diameter, 250 mm long and 5pm particle size) and detection at 254 nm. Tests F and t were performed to verify the presence of the matrix effect. There was matrix effect to all analytes, ranging from -33% (DCA) and 38% (tebuthiuron). Thereby the method was optimized and validated for analysis of diuron, tebuthiuron, and DCPU DCA in surface water using HPLC/UV. The data obtained show that in order to assure the analytical reliability desired the use of the analytical curves in the matrix for the quantification of these analytes in water is required.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Agronomia - FEIS
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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Pós-graduação em Agronomia (Produção Vegetal) - FCAV
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Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV
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Pós-graduação em Agronomia (Produção Vegetal) - FCAV
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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This paper has two main objective the study of the productive space circuit of fertilizers in Brazil. For this, we study the company's operations Vale Fertilizers SA More specifically, the production and consumption of fertilizers in Brazil. In the current globalization the Brazilian countryside know new ways of doing (SANTOS, 1994). This, with less roughness, adopts the Green Revolution package, and introduces inputs to the soil, such as seeders, combines, tractors, herbicides, fungicides and fertilizers (Santos & Silveira, 2001). The examination of the Brazilian case as the agricultural modernization reveals the great vulnerability of modern agricultural regions in the face of globalizing modernization (Santos, 2000: 92). The places that receive capital reproduction of imperatives gain a new medium, is the formation of informational scientific technical means, are the bright spots corresponding to other places (Santos, 1994). Thus, the productive circuits are no longer confined to the environment, but establish connections with distant places (Santos, 1986; Frederick & CASTILLO, 2004). What's more, the policy is now made in the market (Santos, 2000, p.67) and the adoption by the Brazilian government's neoliberal policies, the Brazilian state-owned companies related to fertilizer production circuit are privatized, thereby Brazil makes It is further more dependent on inputs used in the field, including fertilizers
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Pós-graduação em Agronomia (Ciência do Solo) - FCAV
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Under conservation tillage systems is critical to maintaining plant residues from previous crops on the soil surface. A technique called Hormesis aims to increase the amount of straw and also cause a delay in straw decomposition. Therefore, this study aimed to evaluate the agronomic characteristics of corn under no-tillage system subjected to Hormesis. The experiment was carried out at UNESP campus in the city of Botucatu, SP . The experimental was design in completely randomized blocks. The treatments based on the technique of Hormesis were : control (no application) , sub Gliphosate low dosage (12.5 g.ai.ha - 1 ) , sub Gliphosate average dosage (25 g. ai.ha - 1 ) , sub Gliphosate high dose (50 g. ai.ha -1 ), 2,4-D under low dose (100 g. ai.ha -1 ), 2,4-D sub average dosage (200 g. ai.ha -1 ) 2,4- D under high dosage (300 g. ai.ha -1 ) sub Verdict low dose (0.625 g. ai.ha -1 ) sub Verdict average dosage (1.25 g. ai.ha -1 ) , sub Verdict high dosage (2.5 g. ai.ha - 1 ) . In addition, the following characteristics were evaluated: plant height, first ear growth, stem diameter , ear length , number of rows per cob, cob diameter , , percentage of grains on the cob , mass of plant dry matter, and yield. The results showed that all the treatments showed no statistical difference, the maize was not affected with sub doses of herbicides applications under the field and weather conditions in which the experiment was conducted.
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The objective was to evaluate the influence of intervals without rain after the application of mixtures of carfentrazone-ethyl and glyphosate in the effectiveness of control on Commelina benghalensis. The experimental design was completely randomized with 11 treatments, with two rates of the mixture carfentrazone + glyphosate, 30 + 960 (with sequential application at 21 DAA of the mixture 20 + 960 g ha-1) and 50 + 960 g ha-1 of a.i. and five intervals of precipitation 0, 3, 6, 12 and 24 hours after application (HAA), with four repetitions, being an absolute check. The mixture was applied in post-emergence, then was carried out simulations of rain in the predetermined intervals. Were assessed the effectiveness of visual control (0 to 100 %) at 7, 14, 21, 28, 35 and 42 DAA. The results were compared by t test, with 10 % level of probability. It was observed that the application of the herbicides carfentrazone + glyphosate in the evaluated rates and even in the sequential application did not have control of C. benghalensis. The results with the second application are greater than the single application, and the best absorption of the mixture carfentrazone + glyphosate by C. benghalensis when there is a bigger interval between application and rainfall occurrence, and is necessary a minimum interval of 6 HAA for intermediate control of C. benghalensis.