Controle químico de macrófitas aquáticas e indicadores de qualidade ambiental em condições de várzea
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Data
2021-11-12
Autores
Cerveira Junior, Wilson Roberto [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As atividades antropogênicas causam crescimento excessivo das macrófitas aquáticas, que por sua vez, acarretam impactos ecológicos, econômicos e a saúde pública. O controle químico com herbicida é uma forma de manejo destas plantas. Contudo, para aplicação de produtos químicos no ambiente aquático é necessário fazer uma avaliação do impacto desta utilização e o potencial risco ambiental. Assim, o objetivo deste estudo foi avaliar a eficácia dos herbicidas glyphosate, saflufenacil e imazamox isolados e em misturas, com uma posterior aplicação sequencial de glyphosate e imazamox no controle de macrófitas aquáticas e os efeitos sobre indicadores ambientais de qualidade de água em condição de mesocosmos. Para tanto, foram utilizados mesocosmos, com adição de solo e esterco orgânico em metade da superfície do fundo simulando uma área de várzea alagada. Foram realizados dois experimentos, sendo testado no primeiro as doses de 120,0 g i.a. ha-1 de saflufenacil, glyphosate + saflufenacil (1440,0 g i.a. ha-1 + 42,0 g i.a. ha-1; 1440,0 g i.a. ha-1 + 84,0 g i.a. ha-1; 1440,0 g i.a. ha-1 + 168,0 g i.a. ha-1) e 1440,0 g i.a. ha-1 de glyphosate, com uma aplicação sequencial em 75 após a primeira aplicação de 1680,0 g i.a. ha-1 de glyphosate. No segundo foi testado as doses de 800 g ia ha-1 de imazamox, glyphosate + imazamox (1440 + 200 g ia ha-1; 1440 + 400 g ia ha-1; 1440 + 600 g ia ha-1) e aplicação sequencial de 800 g i.a. ha-1 de imazamox realizada 75 dias após a primeira aplicação. O glyphosate isolado apresentou melhor controle das macrófitas aquáticas em relação as misturas. O glyphosate + saflufenacil foi mais eficaz no controle de Hedychium coronarium e Pistia stratiotes e o glyphosate + imazamox foi mais eficaz para Urochloa arrecta e Eirchhornia crassipes. A aplicação sequencial de glyphosate obteve um melhor controle da ressurgência e de plantas que não apresentam eficácia ao invés do uso de imazamox, e não ocorreram alterações significativas nos parâmetros químicos, físicos e biológicos de qualidade de água. Conclui-se que a aplicação de herbicidas (isolados ou em misturas) e uma pulverização complementar pode ser utilizada como estratégia de manejo de controle de macrófitas aquáticas, sem causar alterações nos indicadores de qualidade ambiental.
Anthropogenic activities cause excessive growth of aquatic macrophytes, which in turn lead to ecological, economic and public health impacts. Chemical control with herbicide is a way of managing these plants. However, for the application of chemical products in the aquatic environment it is necessary to carry out an assessment of the impact of this use and the potential environmental risk. Thus, the aim of this study was to evaluate the efficacy of glyphosate, saflufenacil and imazamox herbicides, isolated and in mixtures, with a subsequent sequential application of glyphosate and imazamox in the control of aquatic macrophytes and the effects on environmental indicators of water quality in mesocosm conditions. For this purpose, mesocosms were used, with the addition of soil and organic manure on half of the bottom surface, simulating a flooded floodplain area. Two experiments were carried out, the first being tested at doses of 120.0 g ai ha-1 of saflufenacil, glyphosate + saflufenacil (1440.0 g ai ha-1 + 42.0 g ai ha-1; 1440.0 g ai ha-1 + 84.0 g ai ha-1; 1440.0 g ai ha-1 + 168.0 g ai ha-1) and 1440.0 g ai ha-1 of glyphosate, with a sequential application in 75 after the first application of 1680.0 g ai ha-1 of glyphosate. In the second, doses of 800 g ai ha-1 of imazamox, glyphosate + imazamox (1440 + 200 g ai ha-1; 1440 + 400 g ai ha-1; 1440 + 600 g ai ha-1) were tested and sequential application of 800 g ai ha-1 of imazamox performed 75 days after the first application. The isolated glyphosate showed better control of aquatic macrophytes in relation to the mixtures. Glyphosate + saflufenacil was more effective in controlling Hedychium coronarium and Pistia stratiotes and glyphosate + imazamox was more effective in Urochloa arrecta and Eirchhornia crassipes. The sequential application of glyphosate obtained a better control of upwelling and of plants that do not show efficacy, instead of the use of imazamox, and there were no significant changes in the chemical, physical and biological parameters of water quality. It is concluded that the application of herbicides (alone or in mixtures) and a complementary spraying can be used as a management strategy to control aquatic macrophytes, without altering the environmental quality indicators.
Anthropogenic activities cause excessive growth of aquatic macrophytes, which in turn lead to ecological, economic and public health impacts. Chemical control with herbicide is a way of managing these plants. However, for the application of chemical products in the aquatic environment it is necessary to carry out an assessment of the impact of this use and the potential environmental risk. Thus, the aim of this study was to evaluate the efficacy of glyphosate, saflufenacil and imazamox herbicides, isolated and in mixtures, with a subsequent sequential application of glyphosate and imazamox in the control of aquatic macrophytes and the effects on environmental indicators of water quality in mesocosm conditions. For this purpose, mesocosms were used, with the addition of soil and organic manure on half of the bottom surface, simulating a flooded floodplain area. Two experiments were carried out, the first being tested at doses of 120.0 g ai ha-1 of saflufenacil, glyphosate + saflufenacil (1440.0 g ai ha-1 + 42.0 g ai ha-1; 1440.0 g ai ha-1 + 84.0 g ai ha-1; 1440.0 g ai ha-1 + 168.0 g ai ha-1) and 1440.0 g ai ha-1 of glyphosate, with a sequential application in 75 after the first application of 1680.0 g ai ha-1 of glyphosate. In the second, doses of 800 g ai ha-1 of imazamox, glyphosate + imazamox (1440 + 200 g ai ha-1; 1440 + 400 g ai ha-1; 1440 + 600 g ai ha-1) were tested and sequential application of 800 g ai ha-1 of imazamox performed 75 days after the first application. The isolated glyphosate showed better control of aquatic macrophytes in relation to the mixtures. Glyphosate + saflufenacil was more effective in controlling Hedychium coronarium and Pistia stratiotes and glyphosate + imazamox was more effective in Urochloa arrecta and Eirchhornia crassipes. The sequential application of glyphosate obtained a better control of upwelling and of plants that do not show efficacy, instead of the use of imazamox, and there were no significant changes in the chemical, physical and biological parameters of water quality. It is concluded that the application of herbicides (alone or in mixtures) and a complementary spraying can be used as a management strategy to control aquatic macrophytes, without altering the environmental quality indicators.
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Palavras-chave
Herbicidas, Macrófitas aquáticas, Monitoramento ambiental, Várzea