Pre-and post-emergence herbicides effect on growth, nodulation and productivity of greengram

A field experiment was conducted during Kharif season to study the efficacy of different pre-and post-emergence herbicides for weed management in greengram. Pre-emergence (PE) application of pendimethalin + imazethapyr at 0.75 kg/ha (pre-mix) effectively reduced both the density and dry matter of weeds whereas post-emergence (PoE) application of imazethapyr 10 SL at 55 g/ha significantly reduced Cyperus rotundus. All the PE and PoE herbicides significantly reduced the dry weight of weeds at 30 and 60 days after sowing (DAS) as compared to weedy check. The highest weed control efficiency was recorded in two hand weeding (90.2%), and was followed by pendimethalin + imazethapyr (pre-mix) 0.75 kg/ha applied as PE (86.8%). PoE herbicides (imazethapyr, imazamox+ imazethapyr and clodinafop-propargyl + aciflourfensodium) not only suppressed the crop growth, but also exhibited antagonistic effect on root nodulation. Significantly higher seed yields were recorded under two hand weeding and pendimethalin + imazethapyr at 0.75 kg/ha (PE). Two hand weeding also recorded the highest gross and net returns, and was followed by pendimethalin + imazethapyr (pre-mix) at 0.75 kg/ha (PE). Application of pendimethalin + imazethapyr at 0.75 kg/ha (PE) also gave the highest B: C ratio, and it was followed by two hand weeding. All the PoE herbicides fetched comparatively lower returns and B: C ratio.