Botanical herbicides, System intensification, Weed management
Ten field experiments were conducted at Viswavidyalaya farm during 2004 - 14 in system intensification methodology on SRI rice (Oryza sativa), groundnut (Arachis hypogea), soybean (Glycine max), rapeseed (Brassica campestris), sesame (Sesamum indicum), greengram (Vigna mungo) and blackgram (Vigna aureus) crops grown in inceptisols following annual planning of weed management to find out the efficacy of botanical extracts. In all experiments varied treatments 5-12 numbers were used in RBD with 3-5 replications in plot size 3-4 x 5 m. The botanical extracts (BE) of different plants with 0.25% Tween 80 surfactants were used at 5, 10 and 100% at pre-emergence (PE) in moist soil along with two mechanical weeding (MW) at 20 and 40 DAP. Weedy check (WC), hand weeding (HW) at 20 and MW at 40 days after planting (DAP), pre-emergence (PE) herbicides at 1-2 DAP pretilachlor at 500 g/ha, alachlor at 1500 g/ha or pendimethalin at 750 g/ha + MW at 30 DAP and post-emergence (POE) herbicides quizalofop-ethyl or fenoxaprop-p-ethyl at 50 g/ha at 20 DAP + MW at 40 DAP were also used in different crops as standard check. The experiments on rapeseed and soybean during 2004-05 showed PE Eucalyptus leaf extract attributed 11.2% higher seed yield over WC besides two HW and pendimethalin. During 2010-11 in experiment on SRI rice, the grain yield was 6.35 t/ha in HW, 5.35 t/ha in CC, 5.16 t/ha in Tectona methanol extract while 3.44 t/ha in WC. In another experiment during 2010-11 on sesame, green and blackgram, the botanical extract of Ageratum conyzoides recorded higher growth and yield in sesame and blackgram while Ocimum sanctum extract among the botanicals in greengram exhibited higher harvest index, oil content and also soil nutrient status. In groundnut during 2012, average pod yield of botanical treatments was 32.5% (summer) and 42.5% (Kharif) which was higher than WC. Experiment on SRI rice during 2012-13 revealed that maximum WCE was obtained from HW (91%) followed by chemical control CC (84%) and BE (78%) compared to three MW (67%), two MW (53%) over WC. The mean grain yield data showed that HW recorded 88% followed by CC (79%), BE (76%), three MW (67%) and two MW (36%) over control. The maximum WCE was obtained from HW (91%) followed by CC (84%) and BE (78%) compared to 3 MW 67% and 2 MW 53%.