EFFECT OF DIFFERENT WEED CONTROL METHODS
ON THE YIELD OF TRANSPLANTED AMAN RICE VARIETIES
Tania Sharmin, Mst. Rifat Jahan,
Md. Jafar Ullah and H.M.M. Tariq Hossain*
*Corresponding author: Email-hmtariq@yahoo.com
Abstract
A
field experiment was conducted at Sher-e-Bangla Agricultural University, Dhaka,
Bangladesh during August to December, 2013 in T. aman season with a view to
find out the performance of two transplanted aman rice varieties BRRI dhan56
and BRRI dhan57 under different weed control methods; viz. chemical herbicide Rifit 50EC (Pretilachor 500 g L-1)
@ 1 L/ha (W1), polythene paper (W2), stale seedbed (W3),
one hand weeding at 20 DAT (W4), two hand weedings at 20 and 40 DAT respectively
(W5) and no weeding (control) (W6) using split plot
design. Eighteen different weed species infested the field among which Cyperus michelianus (36.73%), Cyperus esculentus (17.31%) at 30 DAT; Cyperus esculentus (25.13%) Alternanthera sessilis (21.53%) and Cyperus difformis (15.79%) at 60 DAT, Fimbristylis miliaceae (19.50%) at 90
DAT were dominant. Two hand weedings at 20 and 40 DAT (W5) proved
the highest weed control efficiency showing 89.90% at 30 DAT, 59.74% at 60 DAT
and 78.85% at 90 DAT. BRRI dhan56 produced higher (3.70 t ha-1)
grain yield when two times weeding were performed at 20 and 40 DAT. This
variety also produced the longest panicle length (23.39 cm), 1000-grain weight
(23.12 g), grain yield (3.14 t ha1), straw yield (5.16 t ha-1),
biological yield (8.90 t ha-1) and harvest index (35.08%) which were
better than those of the BRRI dhan57. Economic analysis of the weed control
parameters showed that the highest Benefit Cost Ratio, BCR (1.92) was recorded from the chemical
herbicide Rifit 500EC weed control. While the two hand weeding, stale seed bed
and one hand weeding produced 1.79, 1.69 and 1.48 BCR respectively.
Key
words: Transplanted aman
rice, weed control
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