RESUMO
An experiment was conducted at Product Testing Unit, Department of Agronomy, JNKVV, Jabalpur to study the effect of application of propaquizafop and imazethapyr herbicide on weeds associated with blackgram. The experimental field was having mixed weed flora comprising of grassy as well as broad leaved weeds. Nine treatments comprised of four rates of application of propaquizafop+ imazethapyr at 47+70, 50+75, 53+80 and 56+85 g/ha and alone application of propaquizafop (100 g/ha), imazethapyr (100 g/ha), pendimethalin (1500 g/ha) and hand weeding twice at 20 and 40 DAS including weedy check, were laid out in Randomized Block Design with three replications. All herbicide treatments were applied in 500 liters of water per hectare, using flat fan nozzle as per the treatments. The dominant weed flora, species wise weed density, weed biomass, Weed control efficiency and weed index were recorded at different interval. The study revealed that the Echinochloa colona (29.39%) and Dinebra retroflexa (24.30%) were the found as dominant weeds in the field whereas, other monocot weeds like Cyperus iria (18.19%) and dicot weeds like Mullugo pentaphylla (12.23%), Eclipta alba (7.58%) and Alternanthera philoxeroides (8.31%) were also present in less numbers in blackgram under weedy check plots. Among the herbicidal treatments, activity of propaquizafop+imazethapyr mixture at the dose 53+80 and 56+85 g/ha emerged as effective control for the weeds associated with blackgram.
RESUMO
Manual weed control in mustard is very expensive because of its high labour requirement i.e., 150-250 labourers/ha. Chemical weed control again imposes environmental hazards. Mechanical weed control in mustard is not still that popular till date. Due to severe weed competition, the yield reduction in Indian mustard may go as high as 70 per cent. Thus weed control in zero till mustard using its high-density sowing (HDS) was studied in different farmers’ field, at ICAR-CRIJAF, in North 24 PGS and Purulia, from 2018-2022. Fast growing and high- density uniform mustard canopy (100-200 m2) developed at early stages hinders sunlight penetration (up to 99.98 per cent) below its canopy (at 35- 40 days), leading to scanty and under developed growth of different composite weed species at harvest, those germinate or grow below mustard canopy. Weed population below mustard canopy was reduced by 92 to 97 per cent at mustard harvest. It was only 10-80/m2 at harvest over 350-1000/m2 in weedy situation at initial germination. The reduction of dicot weed biomass below matured mustard at harvest was 81-99 percent (5-150g/ m2) percent over weedy plots (500-800/ m2). Reduction of effective flowers/pods of different weeds under matured mustard canopy were up to 99.5 percent. Proper agronomic management practices of HDS mustard e.g., seed rate, date of sowing, uniformity of sowing, irrigation and fertiliser application will eliminate the herbicide application or manual weeding in mustard. Nearly 80 percent mustard plants remain active at harvest. It saves 150-250 labours /ha depending on weed species and its density of germination. Mustard grain yield ranged from 15-30 q/ha depending on management and varieties used. This weed smothering merit of mustard can be used for eco friendly weed control in other wide spaced field/horticultural crops using its dwarf variety (Toria).