Effect of Herbicides on the Density of Broad Leaf Weeds and their Effect on the Growth and Yield Components of Wheat ( Triticum aestivum L.)

摘要

Objective: The aim of the study was to determine the effects of different herbicides on broadleaf weed density and growth as well as the growth and yield components of wheat. It also examined the effects of weed control (by herbicides and hand weeding) on the growth and yield of wheat, the economic benefits of weed control and aspects of environmental safety. Materials and Methods: This experiment was carried out at the Mullah Ghulam Agriculture Research Centre, Afghanistan. Four different types of herbicides namely, methyl chlorophenoxy acetic acid (MCPA) (Agroxone? at 25 1 L ha^?1), triasulfuron (Amber? at g a.i kg^?1), tribenuron methyl (Express? 25 g a.i kg^?1) and pyroxsulam (Merit? at 240 g a.i kg^?1) were tested. The manufacturers? recommended dosage for triasulfuron was applied at the rate of 120 L ha^?1. The other three post-emergence herbicides were applied at the rate of 350 L ha^?1. The herbicides were applied individually at 25 days after sowing (DAS). In another treatment, the weeds were hand weeded at 25, 50 and 75 DAS, while the control plots and were left unweeded. The data was analyzed using SPSS, one-way ANOVA and the Duncan?s test for comparison of means. Results: The results showed that the highest grain yield (2936 kg ha^?1) was obtained from the hand weeded plots, where yields were significantly higher (p ?1) was obtained from the unweeded plots. It was observed that the population density of the broad leaf weeds was lower in the hand weeded plots than that in the other treatment plots. It was observed that tribenuron methyl effectively controlled the weed density of Amaranthus bouchonii, Convolvulus arvensis, Acroptilon repense and Polygonum aviculare at 30 DAS. Conclusion: The study showed that the significantly higher hand weeding treatment followed by treatments with MCPA and triasulfuron herbicides were more effective in case of yield components of wheat and also decreased the population of broad leaf weeds.