Impact of weed management on maize (Zea mays L.) planted at night

Field trial was conducted at Malkandher Research Farm, NWFP Agricultural University, Peshawar, Pakistan, during 2001 to study the effect of selective herbicides on grassy and broadleaf weeds in night planted maize hybrid P - 3203. The treatments were: unweeded control, hand weeding, pre-emergence herbicides; Stomp (pendimethalin 0.75 kg a.i. ha-1), Primextra (atrazine plus metolachlor 2.25 kg a.i. ha-1), Jinong (atrazine 0.90 kg a.i. ha-1), Dual gold (S-metolachlor 1.92 kg a.i. ha-1), and Treflan (trifluralin 1.50 kg a.i. ha-1) and post-emergence herbicides; Banvel (dicamba 0.84 kg a.i. ha-1) and 2,4-D (0.80 kg a.i. ha-1). The predominant weed flora recorded was Echinochloa crus-galli, Leptochloa sp., Cyperus rotundus and Digiteria sanguinalis. The herbicides significantly affected leaf area, cob length, number of kernels cob-1, 500 kernel weight (g), grain yield (t ha-1), weeds density m-2 and weeds biomass m-2. The most effective herbicides in controlling weeds were pendimethalin, atrazine plus metolachlor and S- metolachlor with 65 and 55% each control, respectively as compared to 265 weeds in -2 in unweeded control. Pendimethalin increased yield by 39% atrazine plus metolachlor by 38%, S-metolachlor by 31% and hand weeding by 61%. All the significant parameters of crop were comparable among the hand weeding, pendimethalin, atrazine plus metolachlor and S-metolachlor treated plots. However pendimethalin and atrazine plus metolachlor proved to be the most economical herbicides giving maximum returns of Rs. 35825 and 34582 ha- 1.