Effect of different herbicides on controlling weeds and their effect onyield and yield components of edible pea (Pisum sativum L.)

To study the efficacy of different herbicides on weeds and their effect onyield and yield components of edible pea (Pisum sativum L.), an experimentwas conducted at Malakandher Research Farm, NWFP Agricultural University,Peshawar during 2001-2002 using RCBD, having five replications. Theexperiment comprised of 8 herbicides, hand weeding and a weedy check. Theherbicides included pre-emergence herbicides trifluralin at the rate of 0.12 kgPPI, S-metolachlor at the rate of 1.44 kg, pendimethalin at the rate of 0.99 kgand metribuzin at the rate of 0.35 kg ai ha-1 and the post emergenceherbicides oxadiazon at the rate of 0.36 kg, propaquizafop at the rate of 1.5kg, isoproturon at the rate of 0.63 kg and metribuzin at the rate of 0.35 kg aiha-1. Variety Climax of pea in plot size 5x1.6 m-2 was planted during the lastweek of October, 2001. The data were recorded on percent germination, weeddensity (m-2), phytotoxic effect on crop, plant height at maturity (cm), daysto 50% pod formation, No. of pods plant-1, pod length (cm), number of seedspod-1, 100 seed weight (g), shelling percentage and pod yield kg ha-1.Herbicides metribuzin and S-metolachlor had 50%, while oxadiazon andtrifluralin had 75% phytotoxic effect as determined by chlorosis on pea plants.The phytotoxicity, however disappeared in later growth stages in all theherbicides. All the parameters except number of pods plant-1 and number ofseeds pod-1 were significantly affected by different herbicidal treatments.Minimum weeds m-2 (30.60) and the weed biomass g m-2 (96) were recorded inhand weeded plots followed by 76.80 weeds m-2 and 308 g m-2 weed biomassin post emergently treated metribuzin plots. Percent germination was adverselyaffected by pre emergence herbicides like trifluralin (90.53) and pendimethalin(95.53%). Post emergently applied oxadiazon and metribuzin treated plotsavailed maximum days to 50% pod formation due to their severe phytotoxiceffect on pea plants. Pod length (9.612), No. of seeds pod-1 (6.14) and podyield (4673 kg ha-1) were the maximum in hand weeded plots, followed by postemergently metribuzin treated plots. Moreover, the maximum (43.85 g), 100 seedweight and shelling percentage (41.56) were also recorded in post emergentlymetribuzin treated plots. It is therefore suggested that the hand weeding maybe supplemented with metribuzin as post emergence for effective weedmanagement in edible pea.