Evaluation of postemergence herbicides for broad-spectrum weed control in three cultivars of flooded rice in Nigeria

Abstract

Field trials were conducted in the 1989 wet season and 1989–1990 dry season at Badeggi, Nigeria to evaluate two postemergence herbicide mixtures at varying rates for broad-spectrum weed control in three cultivars of flooded rice. In both trials, irrespective of rice cultivar, the tank-mixture of thiobencarb plus propanil plus silvex at 2.0 + 3.4 + 1.0 kg a.i. ha −1 gave consistently good broad-spectrum weed control and higher rice grain yield comparable to two hand-weedings. Another promising treatment irrespective of rice cultivar was the tank-mixture of butachlor plus propanil at 3.6+ 3.4 kg a.i. ha −1 which effectively controlled weeds and increased rice grain yield. The interaction between cultivar and weed-control treatments had a significant effect on final grain yield at harvest in both trials. In these trials, low rates of tank-mixtures of thiobencarb plus propanil plus silvex at 1.0 + 2.0 + 0.45 and 1.5 + 2.5 + 0.6 kg a.i. ha −1 and butachlor plus propanil at 2.4 + 2.5 kg a.i. ha −1 resulted in significantly higher grain yield of the cultivars Faro 29 or Faro 15 (tall), compared with Faro 27, which is a semi-dwarf rice cultivar