Abstract

BARROS, José Calado; CARVALHO, Mário de  and  BASCH, Gottlieb. Control of weeds in wheat under no-till using reduced herbicide doses and application volumes. Rev. de Ciências Agrárias [online]. 2008, vol.31, n.1, pp.194-200. ISSN 0871-018X.

The aim of the present work was to assess the effect of lower doses than recommended by the manufacturer of the herbicide diclofopmethyl + fenoxaprop – p - ethyl + mefenpyr – diethyl and different application volumes to control the grass weeds Avena sterilis L. and Lolium rigidum G. in post-emergence in no-till wheat and the consequent effect on crop yield. Therefore lower herbicide doses than recommended (1; 1.5 and 2 l ha^-1) were combined with lower application volumes (100; 200 and 300 l ha^-1) at two different weed development stages (beginning of tillering and complete tillering). The recommended herbicide doses to control these weeds vary between 2.5 and 3 l ha^-1 and the application volumes should vary between 350 and 600 l ha^-1 . The results show that the anticipation of the herbicide application (beginning of tillering) leads to a better weed control even using herbicide doses and application volumes lower than recommended. The lower efficiency to control more developed grass weeds and a longer period of competition between crop and weeds for the second application timing (complete tillering) were responsible for the lower crop yields for this application date.

Keywords : Avena sterilis L.; Lolium rigidum G.; development stages; no-till.

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