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Planta Daninha

Print version ISSN 0100-8358

Planta daninha vol.13 no.2 Viçosa  1995

http://dx.doi.org/10.1590/S0100-83581995000200006 

Controle de plantas daninhas em soja com doses reduzidas de herbicidas

 

Soybean weed control with reduced rates of herbicides

 

 

Nilson G. FleckI; Leandro VargasII; Marcos M. da CunhaII

IEng. Agr., PhD, Prof. Adjunto, Bolsista do CNPq, Depto. De Plantas de Lavoura, Faculdade de Agronomia, UFRS, caixa postal 776, Porto Alegre, RS, 90001-970
IIEng. Agr., Aluno do Programa de Pós-Graduação em Agronomia, Faculdade de Agronomia, UFRS

 

 


RESUMO

Durante o ano agrícola 1993/94 foi conduzido experimento de campo na EEA/UFRS em Eldorado do Sul, RS, objetivando avaliar a possibilidade de uso de doses reduzidas dos herbicidas haloxyfop-methyl e sethoxydim para controlar papuã [Brachiaria plantaginea (Link) Hitchc.] na cultura da soja [Glycine max (L.) Merrill. Haloxyfop-methyl foi testado nas doses de 120, 90, 60 e 30+30 g/ha; já sethoxydim o foi nas doses de 220, 165, 110 e 55+55 g/ha. A pulverização dos herbicidas ocorreu 15 dias após a semeadura da soja; nesta ocasião, a maioria das plantas de papuã encontravam-se no estádio de três a quatro folhas. Os tratamentos herbicidas com doses reduzidas em aplicações seqüenciais, tiveram a segunda pulverização realizada 11 dias após a primeira aplicação. Foi obtido controle ao redor de 95% para todos os tratamentos, com pequenas variações não significativas. O rendimento de grãos de soja foi equivalente entre a testemunha capinada e os tratamentos haloxyfop-methyl a 90 e 60 g/ha, sethoxydim a 220, 110 e 55+55 g/ha. Os demais tratamentos foram semelhantes entre si, superando a testemunha infestada, a qual apresentou o menor rendimento de grãos. Os resultados evidenciam a viabilidade da utilização de doses reduzidas, as quais podem alcançar patamares de produtividade tão elevados quanto aqueles obtidos com doses plenas.

Palavras chave: Controle químico, haloxyfop-methyl, sethoxydim, Brachiaria plantaginea, Glycine max.


ABSTRACT

During the 1993/94 growing season, it was carried out a field experiment at the Agronomic Experimental Station of Federal University of Rio Grande do Sul, in Eldorado do Sul, RS, Brazil, in order to evaluate the possibility of using reduced rates of the herbicides haloxyfop-methyl and sethoxydim for Alexandergrass [Brachiaria plafitaginea (Link) Hitchc.] control in soybeans. Haloxyfop-methyl was tested at 120, 90, 60, and 30+30 g/ha, where as sethoxydim was at rates, of 220, 165, 110, and 55+55 g/ha. Herbicide spraying occurred 15 days after soybean sowing; at this time Alexandergrass plants ranged from one leaf to one tiller. Herbicide treatments using reduced rates in sequential applications had the second spraying accomplished 11 days after the first one. It was obtained Alexandergrass control around 95% for all the treatments, with small but not significant variations among them. Soybean seed yield was equivalent for the hoeing check, haloxyfop-methvl at 90 and 60 g/ha and sethoxydim at 220, 110, and 55+55 g/ha. The additional treatments were equivalents among them, but all surpassed the weeded check, which produced the lowest yield. These results evidence the possibility of using reduced herbicides rates, which may reach yield levels as high as those attained with full rates.

Key words: Chemical control, haloxyfopmethyl, sethoxydim, Brachiaria plantaginea, Glycine max.


 

 

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Full text available only in PDF format.

 

 

LITERATURA CITADA

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Recebido para publicação em 29/08/95 e na forma revisada em 18/03/96.

 

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