physicochemical
Contents of 39(1 & 2) 2011 - acharya ng ranga agricultural university
Contents of 39(1 & 2) 2011 - acharya ng ranga agricultural university
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J.Res. ANGRAU 39(1&2)10-13, 2011<br />
EFFECT OF WEED MANAGEMENT PRACTICES ON WEED CONTROL<br />
AND YIELD OF ONION (Alium cepa L) IN VERTISOLS<br />
S. BHARATHI, A.S.RAO and S. SURYA KUMARI<br />
Regional Agricultural Research Station, Lam, Guntur,<br />
Acharya NG Ranga Agricultural University, Rajendranagar, Hyderabad-500 030<br />
ABSTRACT<br />
Field experiment carried out at Regional Agricultural Research Station, Lam, Guntur during rabi 2003 and<br />
2004 with three herbicides as pre-emergence application and integrated with one hand weeding at 45 DAT, weed<br />
free (weeding at 30, 45 and 60 DAT) and unweeded control revealed that integration of oxyflourfen @ 0.15 kg ai<br />
ha -1 , oxadiargyl @ 0.1kg ai ha -1 and pendimethalin @ 1.0 kg ai ha -1 with one hand weeding at 45 days after<br />
transplanting proved to be effective in significantly reducing weed density and increasing the bulb yield over<br />
application of herbicides alone. Among the herbicides oxyflourfen @ 0.15 kg ai ha -1 with one hand weeding at 45<br />
days after transplanting recorded highest bulb yield and was on par with oxadiargyl @ 0.1kg ai ha -1 and pendimethalin<br />
@ 1.0 kg ai ha -1 with one hand weeding at 45 days after transplanting. Hand weeding at 15,30,45 and 60 days after<br />
transplanting has recorded highest weed control efficiency of 80-88%,improved the plant height, number of leaves<br />
per plant, pseudostem diameter, bulb diameter, bulb weight and yield per hectare and significantly superior over<br />
herbicide alone or integrated weed management treatments.<br />
Onion is an important commercial vegetable and<br />
spice crop. In Krishna agroclimatic zone, it is<br />
establishing as an alternate crop to tobacco and other<br />
established mono-cultured crops. Weeds pose a<br />
serious problem in onion because of its poor<br />
competitive ability, non branching habit, sparse<br />
foliage, shallow root system and extremely slow<br />
growth in initial stages. Uncontrolled weeds reduce<br />
bulb yield of onion by 54% when compared with hand<br />
weeding (Tewari et al, 1999). Manual weeding is<br />
laborious, expensive and time consuming. Manual<br />
weeding is not possible in some situations where<br />
sufficient labour is non available at periods of crop<br />
weed comptrol and where field conditions do not<br />
permit. In such situations the control of weeds by<br />
herbicides assumes greater significance because this<br />
is an efficient and economical method (Verma and<br />
Singh 1996). Integrated weed management approach<br />
involving herbicides at low dose and cultural practices<br />
provides economical and eco friendly weed control.<br />
Information on this aspect, in Krishna zone is meagre.<br />
Hence the present study was undertaken.<br />
MATERIALS AND METHODS<br />
A field experiment was conducted at<br />
Regional Agricultural Research Station Lam, Guntur<br />
during rabi 2003 and 2004.The soil of the experimental<br />
site was slightly alkaline in reaction with pH 8.01,EC<br />
0.25 dsm -1 , low in available nitrogen (189 kg ha -1 N),<br />
medium in available phosphorous(36 kg P 2<br />
O 5<br />
ha -1 )<br />
and medium in exchangeable potassium(275 kg K 2<br />
O<br />
ha -1 ). Eight treatments were laid out in randomized<br />
block design with three replications. Onion Variety<br />
Nasik Red was transplanted on both sides of ridges<br />
30cm apart with 10 cm spacing between the<br />
seedlings. All the recommended package of<br />
practices except weed control were followed. The<br />
herbicides were sprayed on third day after<br />
transplanting by knapsack sprayer using flood jet<br />
nozzle as per the treatments with a spray volume of<br />
500 l ha -1 . Observations were recorded on survival<br />
percentage of seedlings, plant height, number of<br />
leaves per plant, bulb characters and bulb yield.<br />
Weed counts were recorded at harvest and were<br />
subjected to square root transformation.<br />
RESULTS AND DISCUSSION<br />
Effect on weeds:<br />
The weed flora of the experimental site<br />
consisted Cynadon sp, Cyperus sp, Trianthema<br />
portulacastrum (33%), Digera arvensis ( 21%)<br />
Celosia argentia (9%),Cleome viscose (7%), Cynodon<br />
dactylon (15%) Cyperus rotundus (10%) and other<br />
weed species (5%). All the weed control treatments<br />
email- bharathi_says@yahoo.com<br />
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