Field experiments were conducted at the fodder farm of ICAR-IVRI, Izatnagar campus, Bareilly. Different doses of atrazine (0.50, 0.75, 1.00 and 2.00 kg/ha) as pre- and post-emergence were applied. The weedy check plots of fodder maize were largely infested by Trianthema portulacastrum, T. monogyna followed by other broad-leaved weeds during 1st year. However, during 2nd year, infestation of these weeds were considerably lower due to higher seed rate and use of ferti-seed-drill. In double-cut fodder sorghum, Trianthema sp. recorded the highest absolute density and absolute frequency followed by sedge (Cyperus esculentus), grasses (Digitaria ciliaris, Setaria glauca) and other broad-leaved weeds (Coccinia grandis, Celosia argentea and Cleome viscosa). The broad-leaved weeds Ageratum conyzoides and Sonchus oleraceus appeared after 1st cutting. In fodder maize, atrazine with all the doses as pre- and post-emergence showed effectiveness. Weeds in weedy check treatment caused a yield reduction of 22.6%, however, in 2nd year the value was 1.7% due to restricted weed growth. Most significant results were recorded in weedy check treatment in which 60.3% yield increment of green fodder maize was registered in 2nd year over 1st year and this resulted in the highest benefit: cost ratio of 3.15. ` 52,400/ha more profit was recorded over broadcasting method of sowing. Higher seed rate (63 kg/ha) along with the use of ferti-seed-drill was equally effective with atrazine treatments. In double-cut sorghum, pre-emergence treatments of atrazine 0.75 kg/ha and above recorded comparatively higher green fodder yield than post-emergence treatments. Weedy check treatment recorded the weed index value of 17.9%. Cumulative green fodder yield (1st and 2nd cut) was highest in weed-free treatment closely followed by atrazine 2.0 kg/ha as pre-emergence treatment. Additional investment of ` 2020/ha after 1st cutting registered the additional net returns of ` 43,100/ha. This indicated the benefits of growing double-cut sorghum and also shown the importance of growing multi-cut and perennial fodder crops. Both the green fodder crops contained atrazine residue at harvest.