Redução da dose e do volume de calda nas aplicações noturnas de herbicidas em pós-emergência na cultura de soja
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Data
1998-06-01
Autores
Ferreira, Marcelo C. [UNESP]
Machado-Neto, Joaquim G. [UNESP]
Matuo, Tomomassa [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira da Ciência das Plantas Daninhas
Resumo
O objetivo deste trabalho foi avaliar o efeito de reduções da dose e do volume de calda nas aplicações noturnas de herbicidas em pós-emergência sobre o controle de plantas daninhas e a seletividade para a cultura da soja. Dois experimentos foram conduzidos na Fazenda de Ensino e Pesquisa da FCAV/UNESP - Campus de Jaboticabal, durante os anos agrícolas de 94/95 e 95/96. As aplicações foram realizadas às 5, 9, 14, 17 e 22h e o volume de calda de 300 l/ha foi reduzido para 75 e 150l/ha. No primeiro experimento foram aplicadas as doses de 432 g de bentazon/ha e 90 g de lactofen/ha, correspondentes a 60% das recomendações de rótulo desses herbicidas, e no segundo, 60 g lactofen/ha e 157,5 g de fomesafen/ha + 2 % de adjuvante (v/v), correspondentes a 40% e 70% das recomendações. Também foram incluídos nos experimentos tratamentos com as recomendações dos rótulos e testemunhas com e sem capina das plantas daninhas durante todo o ciclo da cultura. As aplicações noturnas, realizadas às 5 e 22h, favoreceram significativamente a ação do lactofen com 60% da dose recomendada e desfavoreceram a do fomesafen no controle das plantas daninhas. Não ocorreram diferenças significativas entre os volumes de aplicação estudados, possibilitando o uso de 75 ou 150 l de calda/ha aplicados nos horários mais favoráveis a cada um dos herbicidas. A maior eficiência das aplicações dos herbicidas bentazon, lactofen e fomesafen depende, além das condições ambientais favoráveis no período noturno, das interações específicas entre os herbicidas e as plantas daninhas.
The aim of this research was to evaluate the effect of night-time application on the reduction of spray volume and dose rate in post-emergence herbicide applications and on the selectivity to soybean plants. Two field trials were settled in the experimental farm of the FCAV/UNESP - Jaboticabal/SP, Brazil, during 1994/95 and 1995/96. Spray applications were carried out at 5:00 and 9:00a.m. and 2:00, 5:00 and 10:00p.m. In the first trial the herbicides lactofen and bentazon were applied at 60% of the recommended rate. In the second trial lactofen was applied at 40% of the standard rate and fomesafen at 70%. Control plots were treated with the recommended rate of the herbicides. There were also settled weeded and unweeded plots. It was verified that the reduced dose and spray volume applications carried out at 5:00 a.m. and 10:00 p.m. favored the performance of lactofen with 60% of the standard rate but the contrary ocurred with fomesafen. There was no statistical difference between spray volumes studied which allowed the application of 75 or 150l/ha according to the most favorable period for each herbicide. The effect of herbicides bentazon, lactofen and fomesafen depends, besides the environmental conditions during the night-time, on the interations with these herbicides and the weeds.
The aim of this research was to evaluate the effect of night-time application on the reduction of spray volume and dose rate in post-emergence herbicide applications and on the selectivity to soybean plants. Two field trials were settled in the experimental farm of the FCAV/UNESP - Jaboticabal/SP, Brazil, during 1994/95 and 1995/96. Spray applications were carried out at 5:00 and 9:00a.m. and 2:00, 5:00 and 10:00p.m. In the first trial the herbicides lactofen and bentazon were applied at 60% of the recommended rate. In the second trial lactofen was applied at 40% of the standard rate and fomesafen at 70%. Control plots were treated with the recommended rate of the herbicides. There were also settled weeded and unweeded plots. It was verified that the reduced dose and spray volume applications carried out at 5:00 a.m. and 10:00 p.m. favored the performance of lactofen with 60% of the standard rate but the contrary ocurred with fomesafen. There was no statistical difference between spray volumes studied which allowed the application of 75 or 150l/ha according to the most favorable period for each herbicide. The effect of herbicides bentazon, lactofen and fomesafen depends, besides the environmental conditions during the night-time, on the interations with these herbicides and the weeds.
Descrição
Palavras-chave
spray volume, reduced rate, bentazon, lactofen, fomesafen, volume de aplicação, doses reduzidas, Bentazon, Lactofen, fomesafen
Como citar
Planta Daninha. Sociedade Brasileira da Ciência das Plantas Daninhas , v. 16, n. 1, p. 25-36, 1998.