Influência da chuva na eficácia do glyphosate em mistura com adjuvantes na dessecação de plantas daninhas
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Data
2002-08-01
Autores
Pedrinho Junior, A. F. F [UNESP]
Piva, F. M. [UNESP]
Martini, G. [UNESP]
Felici, G. V. [UNESP]
Durigan, Julio Cezar [UNESP]
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ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira da Ciência das Plantas Daninhas
Resumo
Com o objetivo de estudar a influência do momento da chuva após a aplicação do herbicida glyphosate isolado e em mistura com adjuvantes na dessecação de plantas daninhas, foram instalados dois experimentos na Fazenda Experimental de Ensino e Pesquisa da Faculdade de Ciências Agrárias e Veterinárias, UNESP - campus de Jaboticabal-SP, em duas épocas: inverno de 2000 (junho - agosto) e verão de 2001 (janeiro-março). Os experimentos foram instalados no delineamento experimental de blocos ao acaso, em arranjo fatorial 4 (tratamentos herbicidas) x 5 (períodos livres de chuva simulada) + 1, com quatro repetições. Os tratamentos consistiram da combinação de glyphosate SAqC (360 g e.a. ha-1) isolado ou adicionado de uréia (50 g L-1 de calda) ou óleo vegetal (100 ml L-1 de calda) ou sulfato de amônio (100 g L-1 de calda), com cinco períodos de chuva simulada (1, 2, 4, 6 e > 48 horas após a aplicação), além de uma testemunha. A chuva foi simulada com um sistema de irrigação por aspersão, e a quantidade aplicada variou entre 18 e 19 mm. em ambas as épocas a chuva foi prejudicial à ação do glyphosate, principalmente nos menores períodos livres de chuva após a aplicação. Os sintomas de fitointoxicação apareceram mais rapidamente no verão. A utilização de adjuvantes na calda de pulverização não beneficiou o desempenho do herbicida glyphosate no controle das plantas daninhas, no inverno. A adição de uréia (50 g L¹) é uma boa alternativa para o controle de plantas daninhas, no verão, em situações sujeitas à chuva até duas horas após a aplicação.
The objective of this research was to evaluate the effects of the moment of rain on the activity of the herbicide glyphosate, applied alone and in combination with surfactants, on two growing seasons (winter and summer); at FCAV-UNESP Experimental Station, Jaboticabal-SP, Brazil,, during 2000/2001. The winter experiment was installed from June to August 2000 and the summer one from January to March 2001. The treatments were glyphosate SAqC (360 g e.a. ha-1), alone or in combination with urea (50 g L-1), vegetable oil (100 ml L-1) or ammonium sulfate (100 g L-1), and five periods of simulated rainfall (1, 2, 4, 6 or 48 hours after application) and a check treatment. The experimental design was set up in a randomized block factorial, 5 (herbicides) x 6 (moment of rain) + 1 (controls treatment), with four replications. The artificial rain was provided by a top irrigation system supplying 18-19 mm rain during one hour. The artificial rain reduced the glyphosate action, mainly in the earlier periods. The herbicide symptoms appeared sooner in the summer trial. The use of surfactants in the spray mixture did not improve the performance of glyphosate on weed control during the winter. The addition of urea (50 g L-1), is a good alternative for weed control during summer, when rainfall is expected after the application.
The objective of this research was to evaluate the effects of the moment of rain on the activity of the herbicide glyphosate, applied alone and in combination with surfactants, on two growing seasons (winter and summer); at FCAV-UNESP Experimental Station, Jaboticabal-SP, Brazil,, during 2000/2001. The winter experiment was installed from June to August 2000 and the summer one from January to March 2001. The treatments were glyphosate SAqC (360 g e.a. ha-1), alone or in combination with urea (50 g L-1), vegetable oil (100 ml L-1) or ammonium sulfate (100 g L-1), and five periods of simulated rainfall (1, 2, 4, 6 or 48 hours after application) and a check treatment. The experimental design was set up in a randomized block factorial, 5 (herbicides) x 6 (moment of rain) + 1 (controls treatment), with four replications. The artificial rain was provided by a top irrigation system supplying 18-19 mm rain during one hour. The artificial rain reduced the glyphosate action, mainly in the earlier periods. The herbicide symptoms appeared sooner in the summer trial. The use of surfactants in the spray mixture did not improve the performance of glyphosate on weed control during the winter. The addition of urea (50 g L-1), is a good alternative for weed control during summer, when rainfall is expected after the application.
Descrição
Palavras-chave
weed control, rainfastness, climate, controle de plantas daninhas, Chuva simulada, clima
Como citar
Planta Daninha. Sociedade Brasileira da Ciência das Plantas Daninhas , v. 20, n. 2, p. 263-271, 2002.