Cyperus rotundus control in jute by high density sowing & urea application thrice from sowing,India

Video from Dr Asesh Kumar Ghorai.
Ref. Weed smothering in jute, Cyperus rotunus in particular, by its high density broadcast uniform sowing.
By Asesh Kumar Ghorai, Ex Principal Scientist , Agronomy, ICAR-CRIJAF.
Farmer in demonstration plot: Mr. Sanjoy Sarkar, Swarupnagar, North 24 PGS, WB, India.
Jute being a C3 crop, it cannot compete with the C4 weeds at its early stage and about 40 per cent of total cost of cultivation of jute goes in weeding process alone. Upsurge of new weed flora, labour scarcity, herbicidal resistance and its environmental concern and slow mechanization urged us to control weeds in jute field by its smothering effect. Experiments were conducted at ICAR-CRIJAF, Barrackpore, WB in 2018-19, 2019-20 & 2020-21 with jute (cv. NJ-7010) by its high density broadcast sowing (seed rate 7 kg per ha, seed viability more than 90 percent). Irrigation, fertiliser and pesticides requirements were standardised for this purpose. Only 45 cm wide strip (5% of total area) around the jute field was manually weeded to prevent seed formation of weeds in boarder areas. The dense jute canopy (200-348 /m2) of 29 cm mean height at 25-DAS reduced the incident light at jute base by 90-95 per cent and dominated all C4 weeds. In this 1st year it reduced the grass, broadleaf, sedges weed population (max 52/ m2) and weed bio mass by 98, 98.5, 64.5 and 91.65 per cent respectively over manual weeding twice. Next year at 25 DAS it reduced the grass sedges weed population by 70, and 62% respectively over initial status. In third year most of the grass (507/m2), broadleaved (504/m2) and sedges (52/m2) were smothered by its cover crop effect at early stage (25 DAS). Remaining weeds were rudimentary, incapable of producing seeds. In consecutive three years out, of 20.7 lakh (40 DAS), 26.8 (25 DAS), 34.8 l lakh jute plants/ha (15 DAS), only 3.3, 6.3 and 7.64 lakhs jute plants/ha i.e., 16, 23.5 and 22 % of total initial population were found effective and harvested (125 to135 DAS). The improved experiment of 2nd and 3rd year produced 3.837 & 3.798 t fibre/ha respectively which were at par with manual weeding, chemical herbicide and mechanical weed control process. It eliminated weeding and thinning processes and consumed only 195 and 276 man days/ha from sowing to fibre extraction over conventional method (340 to 365 man days/ha). It saved 89-145 man days/ha (Rs.22500 to 36250/ha). Mesta (Hibiscus cannabinus) also showed similar response as smother crop (2018-19). Pretilachlor 50 EC @ 0.9 l a.i/ha (POE, 7 days) was found effective for weed control in zero till piara crop. Weed smothering by intercropping green garm with jute (1:1)/mixed cropping were also found economic, produced 0.8-1.0 t pulse grain/ha along with 2.7-2.9 t jute fibre and 1.7 to 2 tonnes nutrogen rich (2.35%) pulse waste per ha.. Pre emergence herbicide Pretilachlor 50 EC and Ipfencarbazone 22.8 %SC were found effective for jute. This weed smothering merit of jute can be used for reducing weed seeds in seed bank growing in repeated flushes, it can also be used as cover crops for different crops which will seqester a lot of carbon to soil also. Weed smothering by high density broadcast jute sowing will eliminate dependence on herbicides, mechanical and manual weeding and make jute farming more remunerative and sustainable in nature.
References:
1.Asesh Kumar Ghorai (2020).Weed Smothering in Jute by its High Density Broadcast Sowing. Jaf News. 18(1)2-3.
2. A.K. Ghorai and Suman Roy (2020): Weed Smothering in Jute (Corchorus olitorius L.) by its High Density Broadcast Sowing. J Krishi Vigyan 2022, 10 (2) : 329-335
3.Ghorai, A. K. and Suman Roy. 2022. Weed Smothering (Corchorus olitorius L.) in Jute by its High Density Broadcast Sowing, using Cover Crop Principle. Int.J.Curr.Microbiol.App.Sci. 11(03): 108-119.doi: doi.org/10.205...
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