IMPACT OF SOME SOIL HERBICIDES AS PRE-EMERGENCE AND PRE-PLANTING APPLICATION ON SORGHUM (Sorghum bicolor L. ) PRODUCTIVITY AND ASSOCIATED WEEDS.

Two field experiments were conducted during two successive seasons (2018 and 2019), at Sids Agricultural Research Station, Bani Swif, Egypt, to evaluate efficacy and selectivity of some soilapplied herbicides (Butralin at 120 g, Pendimethalin at 773.5 g and Acetochlor at 840 g a.i. fed.). In addition, hand hoeing (twice) and weed check (control), under influence of different application methods as pre-emergence (experiment 1) or pre-planting (experiment 2) on vegetative growth and grain sorghum were simultaneously examined. Each experiment was laid out in a Randomized Complete Blocks Design, with four replicates. The results showed that there was no difference on efficacy of weed control between two application methods of soil-herbicides whereas there was satisfactory controlling effect of total weeds in both seasons. Also, the results revealed that in the preemergence application gave the highest injury in vegetative growth, which were inversely related between the vegetative growth and yield and its components. Whereas the increasing reduction in number of plants/plot, yield and its components decreased. On the contrary, in pre-planting application there was no adverse effect on vegetative growth, rather there was a positive correlation, whereas increases in number of plants/plot, yield and its components increased, in both seasons. Generally, it is concluded that, sorghum vegetative growth, yield and its components were not affected by these herbicides, so that appear to have good potential for controlling effect on weeds and selectivity of grain sorghum when applied pre-planting (14 days from application) but (pre-emergence) is risky.