Fitorremediação de solo com aplicação de tebuthiuron e vinhaça por espécies de interesse agronômico
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Data
2019-12-09
Autores
Ferreira, Luziane Cristina
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O herbicida tebuthiuron é largamente utilizado na cultura da cana-de-açúcar e pode acarretar prejuízos ao ambiente devido seu elevado potencial tóxico e alta persistência no solo. Assim, esse trabalho teve como objetivo avaliar o potencial de espécies vegetais em diminuir a concentração de tebuthiuron no solo com aplicação de vinhaça. A eficiência do processo de biorremediação foi avaliada quanto: ao desenvolvimento vegetal, aos parâmetros físico-químicos do solo e à ecotoxicidade do meio. Os experimentos foram conduzidos em casa de vegetação utilizando vasos com solo sem histórico de aplicação do herbicida. As espécies potencialmente fitorremediadoras testadas foram: feijão-de-porco (Canavalia ensiformis), feijão-guandu (Cajanus cajan), milheto (Pennisetum glaucum), e mucuna-cinza (Mucuna pruriens (L.) DC.). Como espécie sentinela foi utilizada a Crotalaria juncea. Ao longo do experimento foram avaliados: o diâmetro do colo, a altura da planta e o número de folhas. Ao final, avaliações de massas fresca e seca foram realizadas para as cinco plantas testadas. A fitotoxicidade das amostras nos tratamentos foi determinada nos tempos inicial (zero) e final (50 dias), utilizando sementes de alface como organismos-teste. Os resultados revelaram que o feijão-de-porco e o feijão-guandu não resistiram a presença do herbicida. O milheto apresentou o menor índice de mortalidade e também o melhor desempenho em solos na presença do tebuhiuron associado ou não à vinhaça. Baseado em seu desenvolvimento vegetal a utilização da mucuna-cinza pode ser mais indicada para uso em reformas de canaviais. Sobre as espécies potencialmente fitorremediadoras, de acordo com o desenvolvimento de C. juncea, observa-se que, os vasos que anteriormente foram ocupados por mucuna-cinza, permitiram um melhor desenvolvimento e produção de biomassa para a espécie bioindicadora. Quanto ao teste de ecotoxicidade, a presença isolada do tebuthiuron no solo revelou um potencial tóxico para sementes de L. sativa, mas a aplicação da vinhaça junto ao herbicida favoreceu a redução dessa ecotoxicidade no tempo inicial.
The herbicide tebuthiuron is widely used in sugarcane cultivation and can cause damage to the environment due to its high toxic potential and high soil persistence. Thus, this work aimed to evaluate the potential of plant species in decreasing tebuthiuron concentration in the soil with vinasse application. The efficiency of the bioremediation process was evaluated for: plant development, soil physicochemical parameters and environment ecotoxicity. To evaluate these parameters, the experiments were conducted in a greenhouse using pots with soil with no history of herbicide application. Potential phytoremediation species tested were: jack bean (Canavalia ensiformis), pigeon pea (Cajanus cajan), millet (Pennisetum glaucum), and velvet bean (Mucuna pruriens (L.) DC.). As bioindicator species was used Crotalaria juncea. Throughout the experiment were evaluated: the neck diameter, the plant height and the number of leaves. At the end, fresh and dry mass evaluations were performed for the five plants tested. The phytotoxicity of the samples in the treatments was determined at the initial (zero) and final (50 days) times, using lettuce seeds as test organisms. Results revealed that pigeon bean and jack bean did not resist the herbicide presence. Millet plants showed the lowest mortality rate among all plant species and also presented the best performance in tebuthiuron presence associated or not with vinasse. However, despite of these results for millet, velvet bean was the most suitable for use in sugarcane fields reforming as green manure based on plant development. Among the phytoremediation species, according to the development of C. juncea, it is observed that, although velvet bean and millet had similar results, the vessels that were previously occupied by velvet bean, allowed a better development and production of biomass for the bioindicator species. Regarding the ecotoxicity test, the isolated presence of tebuthiuron in the soil revealed a toxic potential for L. sativa seeds, but the application of vinasse to the herbicide favored the reduction of this ecotoxicity in the initial time.
The herbicide tebuthiuron is widely used in sugarcane cultivation and can cause damage to the environment due to its high toxic potential and high soil persistence. Thus, this work aimed to evaluate the potential of plant species in decreasing tebuthiuron concentration in the soil with vinasse application. The efficiency of the bioremediation process was evaluated for: plant development, soil physicochemical parameters and environment ecotoxicity. To evaluate these parameters, the experiments were conducted in a greenhouse using pots with soil with no history of herbicide application. Potential phytoremediation species tested were: jack bean (Canavalia ensiformis), pigeon pea (Cajanus cajan), millet (Pennisetum glaucum), and velvet bean (Mucuna pruriens (L.) DC.). As bioindicator species was used Crotalaria juncea. Throughout the experiment were evaluated: the neck diameter, the plant height and the number of leaves. At the end, fresh and dry mass evaluations were performed for the five plants tested. The phytotoxicity of the samples in the treatments was determined at the initial (zero) and final (50 days) times, using lettuce seeds as test organisms. Results revealed that pigeon bean and jack bean did not resist the herbicide presence. Millet plants showed the lowest mortality rate among all plant species and also presented the best performance in tebuthiuron presence associated or not with vinasse. However, despite of these results for millet, velvet bean was the most suitable for use in sugarcane fields reforming as green manure based on plant development. Among the phytoremediation species, according to the development of C. juncea, it is observed that, although velvet bean and millet had similar results, the vessels that were previously occupied by velvet bean, allowed a better development and production of biomass for the bioindicator species. Regarding the ecotoxicity test, the isolated presence of tebuthiuron in the soil revealed a toxic potential for L. sativa seeds, but the application of vinasse to the herbicide favored the reduction of this ecotoxicity in the initial time.
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Palavras-chave
Biodegradação, Biorremediação, Ecotoxicidade, Herbicida, Biodegradation, Bioremediation, Ecotoxicity, Herbicide