THE ENVIRONMENTAL EFFECTS OF SOME HERBICIDES ON FABA BEAN CROP AND THE FOLLOWING CROPS

Abstract

Four experiments were carried out for successive seasons 1991/92 and 1992/93 at different sites i.e. Sakha and Sids to investigate the environmental effect of weed management treatments on the growth characters and yield of faba bean (Vicia faba L.}, weeds density, diseases, endogenous hermones, microorganism, following crops and economic evaluation. Every experiment included 3 treatments which were:- 1- Control, hand hoeing twice, 4 and 8 weeks after sowing. Herbicides used : Triazine compound used as selective, pre-emergence herbicide. 2- lgran 80% wp at the rate 1.25 kg commercial/feddan. Terbutryn. 3- Topogard 50% wp at the rate 1.5 kg commercial/feddan. A compination. product containing 35% lgran+ 15% terbuthylazine. The experiment was randomized complete blocks design in six replications. The experimental plot area was 57.6 m2 Faba bean variety Giza 3 in Sakha and Giza 402 in Sids were sown on Nov. 10 and Nov. 2 at •the two sites respectively in 1991/92 season and on Nov. 5 and Nov. 1st at the sites respectively in 1992/93 season. After faba bean harvested the same plots were devided into four equal parts. Seeds of soybean, maize, squash and cucumber were sown in each quarter within the experimental plots On May in the two summer seasons 1992 .and 1993. The results obtained could be summarized as follows:

1: Effect of herbicides on weeds At Sakha 91/92 both herbicides performed as a comparable to each other from the view point of their efficiency against broadleaved weeds except Ammi which appeared •as tolearnt to both herbicides. The prevailed weeds arranged in relative descending order as affected of lgran on weed number as follows:- Cor.(100), Ci.(100), Bet.(99), Pha.(94), Mel.(89) and Amm.(4) As affected of Topogard: Cor.(98), Bet.(97), Pha.(96), Ci.(93), Me1.(89) and Amm.(13).