RESPONSE OF SOYBEAN AND ASSOCIATED WEEDS TO VARIOUS WEED CONTROL TREATMENTS

Abstract

Two field experiments were conducted during two successive seasons of 2007 and 2008 in Meit Nagy Village, Meit Ghamr, Dakahlia Governorate, Egypt, to study the effect of some pre-or post-emergence herbicides either alone or accompanied with hoeing on soybean yield and its components and associated weeds. The results showed that the best treatments in controlling the annual bread leaves, annual grasses and total annual weeds throughout the vegetative period of soybean plants were : The pre-emergence application of Pendimethalin at 0.425 kg a.i./fed or Metribuzin at 0.140 kg a.i./fed followed by one hoeing (21 days after sowing) or post-emergence application of Bentazon at 0.180 kg a.i./fed preceded by one hoeing (21 days after sowing), or using hand hoeing twice (21 and 35 days after sowing) compared with single herbicidal treatments. Treatment of Pendimethalin at 0.425 kg a.i./fed followed by one hoeing improved the growth of soybean plants and resulting in the tallest plants, highest number of pods/plant, number of seeds/pod, seed index, seed yield/plant and per feddan and the highest oil % in the seeds as well as seed protein percentage compared to other weed control treatments.