To study the effect of tillage and weed control methods on weed seed bank and composition
of weed flora in maize (Zea mays L.), a field experiment was conducted at CSK Himachal Pradesh
Krishi Vishvavidyalaya, Palampur during Kharif seasons of 2002 and 2003. The weed seed bank
study revealed that while raised seedbed resulted in lowest number of seeds of D. sanguinalis, E.
colona and P. dichotomiflorum at 0-10 cm depth, their population was reduced to a lowest level by
zero tillage at 10-20 cm and 20-30 cm soil depths. However, lowest number of C. benghalensis seeds
was recorded in zero tillage at all the soil depths. Dynamics of weed flora followed the trend of weed
seed distribution in the soil and resulted in significantly lowest population and dry matter of D.
sanguinalis, E. colona and B. ramosa in raised seedbed and of C. benghalensis in zero tillage plots.
Conventional tillage was the next best in significantly reducing the population and dry matter of D.
sanguinalis and C. benghalensis, thereby being statistically at par with raised seedbed significantly
increased the grain yield of the maize. Atrazine 1.5 kg ha-1 being at par with acetachlor 1.25 kg ha-
1 resulted in significantly lower count and dry matter of D. sanguinalis, E. colona, Commelina
benghalensis and other weeds. Aceatchlore 1.25 kg ha-1 gave complete control of B. ramosa.
Consequently, atrazine and acetachlor increased the grain yield of maize by 75.2 and 71.7 per cent,
respectively over unweeded check