-The technology that employs genetic modifications brought a significant increase in the utilization of glyphosate. Transgenic soybean has been suffering injury, even though it possesses a resistance mechanism to glyphosate. Currently, there are only a few studies on the dynamics of glyphosate in transgenic soybean planted in soils with different textures interacting with phosphorus concentrations. This study focused on assessing the effects of glyphosate in transgenic soybean plants on different types of soil and at different phosphorus levels. The experimental design was completely randomized, in factorial design: 2 x 6 x 3, that being 2 soil types, 6 doses of glyphosate and 3 levels of phosphorus, and four replications. Plants were cultivated for thirty days in pots with two types of soil, one being clayey (RedYellow Latosol) and the other sandy (Quartzarenic Neosol). They received one, two, and three times the maintenance dose of fertilization of phosphorus, corresponding to: 170, 250 and 330 kg of P 2 O 5 ha
A B S T R A C TTo increase the efficiency in the control of weeds, it is common the use of a mixture of the herbicides glyphosate and 2,4-D in the desiccation. This paper aimed to evaluate the residual effect of these two herbicides on the development of maize plants, in soils of different textures. The experiment was conducted in a greenhouse, in 2015, in a completely randomized design in a 2 x 2 x 7 factorial scheme, corresponding to two soils (Red Yellow Latosol and Quartzarenic Neosol), two herbicide application times (5 and 10 days before maize sowing) and seven doses of herbicides (recommended dose of glyphosate, recommended dose of 2,4-D; mixing the recommended doses of glyphosate and 2,4-D; two, ten and fifty times the recommended doses in admixture; and one control), with 4 replicates. After emergence of maize plants, the following variables were evaluated: phytotoxicity, plant height, chlorophyll a and chlorophyll b, shoot fresh and dry matter and root dry matter. In general, there was lower residual effect on the Red Yellow Latosol at all the doses of the herbicides and in the interval of 10 days between the desiccation and sowing.Efeito residual da mistura glifosato e 2,4-D em milho "safrinha" em solos de diferentes texturas R E S U M O Para aumentar a eficiência no controle de plantas daninhas é comum o uso em dessecação da mistura dos herbicidas glifosato e 2,4-D. Objetivou-se, neste trabalho, avaliar o efeito residual da aplicação desses dois herbicidas sobre o desenvolvimento de plantas de milho em solos de diferentes texturas. O experimento foi conduzido em casa de vegetação, no ano de 2015, em delineamento inteiramente casualizado, no esquema fatorial 2 x 2 x 7, sendo dois solos (Latossolo Vermelho Amarelo e Neossolo Quartzarênico), duas épocas de aplicação dos herbicidas (5 e 10 dias antes da semeadura do milho) e sete doses dos herbicidas (dose recomendada de glifosato; dose recomendada de 2,4-D; mistura das doses recomendadas de glifosato e 2,4-D; duas, dez e cinquenta vezes as doses recomendadas em mistura e uma testemunha), com quatro repetições. Após a emergência das plantas de milho foram avaliados os seguintes parâmetros: fitotoxicidade, altura de plantas, clorofilas a e b, massa fresca e seca da parte aérea e massa seca da raiz. Em geral, ocorreu menor efeito residual no Latossolo Vermelho Amarelo em todas as doses dos herbicidas e no intervalo de 10 dias entre a aplicação e a semeadura.
The practice of liming may influence the leaching of herbicides in soils, especially those with weak acid character, such as picloram. The study on leaching, preserving soil structure, is an important factor when one intends to understand the dynamics of herbicides and environmental impacts. Thus, the effect of liming on picloram leaching in a dystrophic Red Yellow Latosol under field conditions was studied using a bioindicator plant. The experiment was set up in a completely randomized design (CRD), in split-plot scheme, with factorial in the plot. The factors of the plot corresponded to two soil conditions (presence and absence of liming) and 5 picloram concentrations (0; 384; 768; 1152; 1536 g ha-1), and the factor of the subplot was 5 soil depths (0-8, 8-16, 16-24, 24-32 and 32-40 cm), with four replicates. Pipes were introduced into the soil and, in part of the treatments, limestone was applied superficially. After ninety days, the different doses of picloram were applied on the surface of each pipe and these pipes were withdrawn after an accumulated rainfall of 128 mm, to perform the bioassay using cucumber plants (Cucumis sativus). Evaluations of plant development (phytotoxicity and shoot biomass) were carried out 21 days after sowing. It was concluded that picloram showed high leaching rate under all studied conditions and liming increased picloram leaching at doses lower than 768 g ha-1.
RESUMO Estudos sobre compostos orgânicos voláteis (COVs) produzidos por fungos conidiais sapróbios da Amazônia (FCSA) ainda são inexistentes. Assim, verificou-se a produção de COVs de FCSA e, seu potencial no controle de fitopatógenos in vitro. Utilizou-se os FCSA Beltrania rhombica, Brachysporiella sp., Dictyochaeta sp., Gonytrichum sp. e avaliou-se a produção de COVs através da germinação e viabilidade de esporos dos fitopatógenos e, crescimento micelial, conforme metodologias de (2) e (10), com adaptações. Houve redução de germinação de esporos de Colletotrichum musae (63,56%) frente à exposição a B. rhombica, Brachysporiella sp. (86,66%), Dictyochaeta sp. (79,68%) e Gonytrichum sp. (85,71%). Os fitopatógenos C. truncatum, C. musae e Fusarium sp. quando expostos a COVs de Brachysporiella sp., Dictyochaeta sp. e Gonytrichum sp. apresentaram esporos inviáveis após 3 e 7 dias de exposição. Os COVs dos FCSA reduziram o índice de velocidade do crescimento micelial e inibiram o crescimento micelial de Sclerotinia sp. e S. sclerotiorum; bem como redução da produção de escleródios na exposição aos COVs de B. rhombica, B. gayanaa e D. fertilis. Conclui-se que os FCSA estudados apresentam produção de COVs, com potencial para o controle biológico de doenças de plantas.
The waste application of swine activities is a common practice in many regions; however, there are uncertainties about the risks associated with applications for agriculture. This study presents the assimilable nitrogen transport in lysimeters submitted to reuse water rates and irrigation rates, with cauliflower crop (Brassica oleracea L.), Verona CMS variety from August to October 2014. Three swine water reuse rates were applied (0, 50 and 150 m 3 ha -1 ) and three irrigation rates (100%, 125% and 150% of potential evapotranspiration of culture -ETc) with three repetitions. Leached samples were collected at 10, 20, 30 and 40 days after the application of reuse water (DAAR). The total Kjeldahl nitrogen (TKN) leaching increased with increasing irrigation rates in the lysimeters without water reuse, with averages of 7.84 to 22.78 mg L -1 . Other forms of nitrogen as nitrite (NO2 -) and nitrate (NO3 -) showed a higher concentration to 40 DAAR. However, there was a reduction in the leaching of these elements with increasing irrigation rates. The irrigation rates 125 and 150% and the rate 150 m 3 h -1 transported NO3in lower concentrations. Keywords: evapotranspiration, swine waste, cauliflower. PEDROSA, T. D.; SCHNEIDER, R. M.; WOLF, G.; SOUZA, A. P.; LIMA, W. H. S.; ANDRADE, E. A. TRANSPORTE DE NITROGÊNIO EM FUNÇÃO DA APLICAÇÃO DE ÁGUA DE REUSO E LÂMINAS DE IRRIGAÇÃO 2 RESUMO A aplicação de resíduos de atividades suinícolas é uma prática que vem ganhando espaço em alguns países, todavia, persistem incertezas quanto aos riscos associados a aplicações com fins agrícolas. Neste trabalho apresenta-se o transporte de nitrogênio assimilável em lisímetros submetidos a taxas de água de reuso e lâminas de irrigação, com cultivo de couve-flor (Brassica Oleracea L.) variedade Verona CMS no período de agosto a outubro de 2014. Foram aplicadas 638 Nitrogen transport due... Irriga, Botucatu, v. 23, n. 4, p. 637-648, outubro-dezembro, 2018três taxas de água de reuso da suinocultura (0, 50 e 150 m 3 ha -1 ) e três lâminas de irrigação (100%, 125% e 150% da evapotranspiração potencial da cultura -ETc), com três repetições. Foram coletadas amostras do lixiviado aos 10, 20, 30 e 40 dias após a aplicação da água de reuso (DAAR). A lixiviação de nitrogênio total Kjeldahl (NTK) foi crescente com o aumento da lâmina de irrigação nos lisímetros sem água de reuso, com médias de 7,84 para 22,78 mg L -1 . As demais formas de nitrogênio, como nitrito (NO2 -) e nitrato (NO3 -), apresentaram maiores concentrações aos 40 DAAR, porém, houve redução na lixiviação desses elementos com o aumento da lâmina de irrigação. As lâminas 125 e 150% da ETc e a taxa 150 m 3 ha -1 transportaram NO3em menor concentração.Palavras-chave: evapotranspiração, resíduos de suinocultura, couve-flor.
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