Effect of time and number of harrowings on weed growth and rice yield [Philippines]
1988
Estorninos, L.E. Jr. | Moody, K. (International Rice Research Inst., Los Banos, Laguna (Philippines))
The experiment was conducted in Jaen, Nueva Ecija [Philippines] in the 1987 dry and wet seasons to evaluate the effect of time and number of harrowings and weed control methods on weed growth and rice yield. In the dry season, weed weights and yields were not affected by the time and number of harrowings. Herbicides did not reduce weed weights except when thiobencarb-2,4-D was applied in the treatment which had four passes of a harrow one day before transplanting (DBT). Superior yields were obtained from the weeded plots compared to the untreated plots regardless of the time and number of harrowings. In the wet season, weed weights from plots that received two passes of a harrow one DBT were significantly higher than those from plots which received two passes of a harrow 11, 6, and 1 DBT. Yields did not differ between the times and number of harrowings. All the plots which were weeded yielded significantly higher than those which were not weeded. Superior yields were obtained from the hand weeded plots over the herbicide weeded plots except when thiobencarb-2,4-D was applied when there were two passes of harrow one DBT and two passes 6 and 1 DBT and when pretilachlor + fenclorim was applied and then two passes of a harrow at 11, 6, and 1 DBT.
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