Planta Daninha (Mar 2012)
Crescimento de espécies bioindicadoras do residual do herbicida (imazethapyr+imazapic), semeadas em rotação com arroz Clearfield® Growth of residual herbicide (imazethapyr+imazapic) bio-indicators sown in rotation with Clearfield® rice
Abstract
Neste trabalho, determinou-se o efeito residual do herbicida Only® (imazethapyr+imazapic) sobre plantas de milho, pepino, rabanete e tomate, semeadas em solo no qual o herbicida foi aplicado há 1.100 dias. O estudo foi realizado em casa de vegetação, com o delineamento experimental de casualização por bloco, com quatro repetições por tratamento. Os tratamentos avaliados foram o residual do herbicida Only® aplicado sob as plantas de arroz CL na safra 2006/2007, nas doses de 0, 100, 150 e 200 g ha-1 do produto comercial, acrescido de 0,5% do adjuvante Dash®. Foram semeadas sob as parcelas 15 sementes de cada espécie bioindicadora (milho, pepino, rabanete e tomate), sendo estas desbastadas para 10 plantas após a germinação. Após 60 dias da data da semeadura, foram avaliadas a altura de plantas, a massa seca da parte aérea e a massa seca das raízes, sendo esta última não realizada nas plantas de milho e de pepino. Os dados obtidos foram submetidos à análise da variância (pThis work aimed to determine the residual effect of the herbicide Only® (imazethapyr+imazapic) on corn, cucumber, radish and tomato grown in soil where the herbicide was applied 1.100 days earlier. The experiment was carried out in a greenhouse in a randomized block design, with four replicates per treatment. The treatments were the residual herbicide applied under Only® rice CL plants in the 2006/2007 crop season at doses of 0, 100, 150, and 200 g ha-1 of the commercial product, plus 0.5% of adjuvant Dash®. Fifteen seeds of each bio-indicator (corn, cucumber, radish and tomato) were sown in the plots and thinned to 10 plants after emergence. After 60 days of sowing, the variables plant height, aboveground dry biomass and root dry biomass were measured, except the latter for the corn plants. Data were subjected to analysis of variance (p < 0.05) and tested by polynomial regression models. It was concluded that there was a residual activity of the herbicide Only® (imazethapyr+imazapic) applied under greenhouse conditions, 1,100 days after herbicide application DAA, negatively affecting plant height and aboveground dry biomass of corn, cucumber, radish and tomato. Thus, these species can be used as bio-indicators of residual activity of the commercial mixture of herbicides (imazethapyr + imazapic). Radish and tomato were more sensitive to the presence of the product, compared to corn and cucumber.
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