EFFECTS OF HERBICIDES ON THE PRODUCTIVITY OF FODDER MAIZE WITH ESPECIAL REFERENCE TO PRE‐EMERGENCE APPLICATIONS OF 2,4‐D‐AMINE

Abstract

Summary. The effectiveness of pre‐emergence applications of 2,4‐D for weed control in maize was studied In five experiments, in comparison with other herbicide treatments. 2,4‐D‐aimne applied before crop emergence gave satisfactory weed control if the subsequent conditions were wet, but post‐emerge nee applications only killed some species (Chenopodium album and Atriplex patula.) A combination of 2,4‐D‐amine, applied pre‐emergence to a moist soil and subsequently as a foliar spray, controlled completely C. album, A. patula, Stellaria media and Veronica spp. Pre‐emergence applications of simazine gave better weed control with less need for rain soon after application. Only A. patula was usually resistant. Pre‐emergence treatments of atrazine killed all weeds whilst linuron controlled S. media, A. patula., C. album and Sonchus oleraceus but not Veronica spp.Irrigation experiments showed that weed competition for water was largely responsible for the depressions in the early growth of maize when the conditions were dry. Final yield largely reflected the degrees of weed control attained by the herbicidal treatments. Only 2,4‐D applied pre‐emergence, and followed by heavy rain caused a direct depression in yield.Effects des herbicides sur la productivityé du mals fourrage avec référence particuliére aux applications en pré‐levée du 2,4‐D amine