Comportamento no solo e tolerância de culturas a herbicidas auxínicos

• Autor(a) principal: D'antonino, Leonardo
• Data de Publicação: 2008
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1094
• topic: Picloram; Persistência no solo; Lixiviação; Fitorremediação; Culturas sucessivas; Picloram; Persistence in soil; Leaching; Phytoremediation; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

The objective of this work was to evaluate the tolerance of corn and sorghum crops to herbicides picloram and 2,4-D, the effects of such crops and spontaneous vegetation in the persistence of these herbicides in the soil, and also the leaching of picloram in Red Yellow Ultisol and Red Yellow Latosol with different levels of pH. In the first test, it was evaluated the tolerance of corn and sorghum to 2,4-D and picloram in field conditions. To assess the tolerance of maize and sorghum, plants were collected over time to determine their respective growth curves. In the second experiment, it was evaluated the effect of these crops and spontaneous plants in the persistence of these herbicides in the soil. This test was conducted in greenhouse, using cucumber (Cucumis sativus) as indicator plant in pots containing samples of soil collected in the field experiment in different periods after application of herbicides. In the third test, it was evaluated the leaching of picloram in a Red Yellow Ultisol and a Red Yellow Latosol, with different levels of pH. For that, PVC columns with 50 cm length were filled with soil, being applied on them 160 g ha-1 of picloram and then simulated rainfall of 40, 80 and 120 mm. After 72 hours, it was made a side opening on the columns and Cucumis sativus was planted along it, as an indicator species. It was found that maize plants had their growth affected by herbicides and accumulated smaller quantities of dry matter when grown in soil with picloram + 2,4-D residues, while sorghum plants were tolerant. As for the residual effect of the evaluated herbicides on soil, it was not influenced by the type of crops or soil management (maize, sorghum or spontaneous vegetation). There was no sign of intoxication in the indicator plants grown in soil samples collected in the areas treated with 2,4-D in the evaluation from the 42 DAS. However, in plants grown in soil samples collected in the plots that received the mixture picloram + 2,4-D, only from the 150 DAS there were no more symptoms of picloram intoxication on the indicator plants. It was also verified that picloram showed high leaching rate in all soils and that its movement in the soil profile was influenced by the volume of simulated rain, by the soil pH and also by other soil characteristics. Increasing the pH of the Red Yellow Latosol raised the leaching index of picloram in the soil.