Weed dynamics, weed
control efficiency and yield of aerobic rice as influenced by different weed
management practices in eastern U.P.
R.K. Parihar1,
V.K. Srivastava2, S. Kumar3*, V. Kumar4 and
Sanjay-Swami5
1Pusa Farm, Dr.
Rajendra Prasad Central Agricultural University, Samastipur-848 125, India
2Department of
Agronomy, Institute of Agricultural Sciences, Banaras Hindu University,
Varanasi-221 005, India
3Rabindra Nath
Tagore Agricultural College, Birsa Agricultural University, Ranchi- 814 157,
India
4Muga Silkworm Seed
Organization, P-3 Unit, Rompara- 794 108, India
5School of Natural
Resource Management, College of Post graduate Studies in Agricultural
Sciences, Central Agricultural University, Umiam (Barapani)-793 103, India
*Corresponding Author Email : sksandeepkumarrao@gmail.com
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Abstract
Aim:
To identify the best sequence of pre- and post-emergence herbicides for
achieving better weed control efficiency in aerobic rice.
Methodology: A field experiment was conducted in Randomized Block
Design with eleven treatment combinations, replicated thrice.? The dominant
weeds in field were C. dactylon, E. colona and E. crusgalli
among grasses, C. rotundus, C. difformis and F. maliaceae among
sedges and C. axillaris and P. niruri among broad-leaf weeds.
Treatments consisting sequential application of two pre-emergence application
[Pendimethalin (30 EC) @ 1.00 kg a.i. ha-1; Butachlor (50 EC) @
1.5 kg a.i. ha-1] followed by three post emergence herbicides
[Bispyribac-Na (10% SC) @ 35 g a.i. ha-1; 2, 4-D Na salt (80 WP) @
0.06 kg a.i. ha-1; Almix (CME + MSM ) (20 WP) @ 40 g a.i. ha-1]
and straw mulching @ 4 t ha-1;? Mechanical weeding at 20 and 45
DAS, weed free and unweeded check.?
Results:
Among herbicidal treatments, pre-emergence application of pendimethalin at
3-4 DAS fb Bispyribac-Na at 15-20 DAS as post-emergence was most
effective in minimizing weed density (4.81 m-2), biomass (6.20 g m-2),
weed index (1.11%) and in enhancing the weed control efficiency (84.50%),
grain yield (3.68 t ha-1) and straw yield (4.87 t ha-1)
over rest of the treatments.
Interpretation: Sequential application of pendimethalin
at 3-4 DAS fb bispyribac-Na at 15-20 DAS is prominent in enhancing
herbicide efficacy and reducing weed flora abundance resulting in higher weed
control efficiency and grain yield due to their broad spectrum weed control.
Key
words:
Aerobic rice, Grain yield, Weed biomass, Weed dynamics
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