Potencial alelopático de Crotalaria juncea no controle de plantas daninhas da cultura da cana-de-açúcar (Saccharum spp.)
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Data
2021-10-19
Autores
Alves, Gabriela Mendes
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Universidade Estadual Paulista (Unesp)
Resumo
O cultivo de leguminosas em área de reforma de canaviais é muito utilizada, devido à capacidade dessas espécies de recuperação do solo e à fixação de nitrogênio, o segundo nutriente mais absorvido pela cana-de-açúcar (Saccharum spp.). As culturas mais utilizadas nessa prática são a soja, o amendoim e, em menor escala, a crotalária. Crotalaria spp. tem propriedades diferenciadas, ressaltando-se seu potencial alelopático, ou seja, seu potencial de inibição do desenvolvimento de outras espécies. Diante disso, o objetivo deste estudo foi avaliar o efeito de concentrações de extrato aquoso de Crotalaria juncea sobre quatro espécies infestantes de canaviais colhidas em pleno estágio vegetativo (33 dias após a semeadura - DAS) e reprodutivo (115 DAS), sendo confeccionados extratos aquosos em ambos estágios vegetativo a 0,5 g/mL, considerado como concentração 100% e posteriormente diluído para as concentrações 2,5%, 5%, 10% e 25%, utilizando a água (0%) como testemunha absoluta. Como plantas alvo foram utilizadas a mucuna-preta (Mucuna pruriens), corda-de-viola (Ipomoea nil), capim-colonião (Panicum maximum) e capim-braquiária (Urochloa decumbens). Foram montadas placas de petri com 5 sementes de cada espécie, irrigadas com os diferentes extratos. Com base na análise de variância, observou-se efeito de controle significativo do extrato de C. juncea 33 DAS a 100% de todas as infestantes avaliadas e efeito controle significativo do extrato de C.juncea 115 DAS de I. nil e P. maximum.
The use of leguminous plants in sugarcane reform areas is widely used, due to these species' capacity for soil recovery and nitrogen fixation, which is the second most absorbed nutrient by sugarcane (Saccharum spp.). The most used crops in this practice are soybeans, peanuts and, to a lesser extent, crotalaria. Crotalaria spp. has different properties, with particular emphasis on its allelopathic potential, i.e. its potential to inhibit the development of other species. Thus, the objective of this study was to evaluate the effect of different concentrations of Crotalaria juncea aqueous extract on four invasive species of sugarcane plantations harvested in vegetative stage (33 days after sowing - DAS) and reproductive stage (115 DAS), preparing aqueous extracts in both vegetative stages at 0,5 g/mL, considered as 100% concentration and then diluted to concentrations 2,5%, 5%, 10% and 25%, using water (0%) as absolute witness. As target plants were used Mucuna pruriens, Ipomoea nil, Panicum maximum and Urochloa decumbens. Petri dishes were set up with 5 seeds of each species, irrigated with the extracts. Based on the analysis of variance, significant control effect of C. juncea extract 33 DAS to 100% of all weeds evaluated and significant control effect of C. juncea extract 115 DAS of I. nil and P. maximum were observed.
The use of leguminous plants in sugarcane reform areas is widely used, due to these species' capacity for soil recovery and nitrogen fixation, which is the second most absorbed nutrient by sugarcane (Saccharum spp.). The most used crops in this practice are soybeans, peanuts and, to a lesser extent, crotalaria. Crotalaria spp. has different properties, with particular emphasis on its allelopathic potential, i.e. its potential to inhibit the development of other species. Thus, the objective of this study was to evaluate the effect of different concentrations of Crotalaria juncea aqueous extract on four invasive species of sugarcane plantations harvested in vegetative stage (33 days after sowing - DAS) and reproductive stage (115 DAS), preparing aqueous extracts in both vegetative stages at 0,5 g/mL, considered as 100% concentration and then diluted to concentrations 2,5%, 5%, 10% and 25%, using water (0%) as absolute witness. As target plants were used Mucuna pruriens, Ipomoea nil, Panicum maximum and Urochloa decumbens. Petri dishes were set up with 5 seeds of each species, irrigated with the extracts. Based on the analysis of variance, significant control effect of C. juncea extract 33 DAS to 100% of all weeds evaluated and significant control effect of C. juncea extract 115 DAS of I. nil and P. maximum were observed.
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Crotalaria, Cana-de-açúcar, Ervas daninhas, Alelopatia