Bioactivity of herbicides used to soybean on sunflower crop in succession/Atividade residual de herbicidas usados na soja sobre o girassol cultivado em sucessao

• Published in: Ciência rural 2012-11, Vol.42 (11), p.1929
• Main Authors: Dan, Hugo de Almeida, Dan, Lilian Gomes de Moraes, Barroso, Alberto Leao de Lemos, Procopio, Sergio de Oliveira, de Oliveira, Jr., Rubem Silverio, Braz, Guilherme Braga Pereira, Alonso, Diego Goncalves
• Format: Article
• Language: Spanish
• Subjects: Glycine; Herbicides
• ISSN: 0103-8478

The sunflower is a oilseed crop kind of prominence before the cultures used in succession in the Brazil. However, little information concerning the effects of residual activity of herbicides on the crop in this region are known. The aim of this study was to evaluate the residual activity of herbicides in weed management in pre and post-emergence soybean and evaluate its effects on sunflower crop in succession. In field experiments we adopted the randomized block design with four replications, being appointed nine treatments (kg of i.a. [ha.sup.-1]): imazaquin (0.161), diclosulan (0.035), sulfentrazone (0.600) and flumioxazin (0.050) in pre emergence applications, and chlorimuron-ethyl (0.015), imazethapyr (0.060), imazethapyr (0.100) and fomesafen (0.250) applied post emergence soybean and a control without herbicide. One bioassay was differentiated by the treatments contained in each treatment and soil samples collected at six different times (0, 35, 70, 105, 140 and 200 days after application); evaluated the dry matter accumulation of sunflower plants as a function of time of sample collection. The results showed that: imazethapyr (0.1kg [ha.sup.-1]) and diclosulan (0.035kg [ha.sup.-1]) caused a reduction in sunflower yield. Sensitivity to diclosulan continued throughout the interval evaluation of the range of bioassay. Key words: carryover, Helianthus annuus, Glycine max, bioactivity. O girassol e uma oleaginosa de destaque entre as culturas utilizadas em sucessao a soja na regiao dos cerrados. No entanto, poucas informacoes referentes aos efeitos da atividade residual de herbicidas aplicados na soja sobre o desenvolvimento e rendimento do girassol sao conhecidas. Visando avaliar a atividade residual de herbicidas, aplicados em pre e pos-emergencia na cultura da soja sobre o girassol cultivado em sucessao, foram conduzidos ensaios em campo e em casa de vegetacao. No ensaio de campo, foram empregados nove tratamentos (doses em kg de i.a. [ha.sup.-1]): imazaquin (0,161), diclosulam (0,035), sulfentrazone (0,600) e flumioxazin (0,050), em aplicacoes de pre-emergencia, e chlorimuronethyl (0,015), imazethapyr (0,060), imazethapyr (0,100) e fomesafen (0,250), aplicados em pos-emergencia da soja, mais uma testemunha (sem herbicida). Um bioensaio foi conduzido em casa de vegetacao com as amostras de solo dos tratamentos coletadas em seis epocas distintas (0, 35, 70, 105, 140 e 200 dias apos a aplicacao). Os resultados permitem concluir que o imazethapyr (0,100k