Duary et al.

diets of many people in Asia (Kaur and Sharma,

It was observed that the average relative humidity

2013). In India, it is grown in 2.76 m ha in almost all

in the crop season was quite higher than the long

the states with an average productivity of only 317

term average. The soil of the experimental plot was

kg/ ha. One of the reasons for such a low productivity

loamy sand in texture, acidic in soil reaction with

is its casual cultivation on marginal lands without

low level of organic carbon and available nitrogen,

caring for weed management. Weed competition

but medium level of available P ₂ O ₅ and K ₂ O. Weed

may result upto about 53% yield reduction in

competitiveness of six green-gram cultivars was

green-gram (Kundu et al. , 2011). Considering the

evaluated under two different situations– one

diversity of weed problem, no single method of

under weedy and another with hand weeding (HW)

weed control can reach the desired level of efficiency

at 30 days after sowing (DAS). Altogether there

under all situations. As an important component

were twelve different treatment combinations viz .

of integrated weed management, increasing crop

‘B 1’ (‘Sonali’) - weedy, ‘B 105’ (‘Panna’) - weedy,

cultivar competitiveness may be an attractive low-

‘PDM 84-139’ (‘Samrat’) - weedy, ‘WBM 34-1-1’

cost weed management strategy, which is easy to

(‘Bireshwar’) - weedy, ‘PDM 54’ - weedy, ‘WBM 04-

deliver to the farmers. But in India, much work has

5’ (‘Sukumar’) - weedy, ‘B 1’ (‘Sonali’) - one HW, ‘B

not yet been done on screening of weed competitive

105’ (‘Panna’) - one HW, ‘PDM 84-139’ (‘Samrat’)

crop cultivars in general and particularly in pulses.

- one HW, ‘WBM 34-1-1’ (‘Bireshwar’) - one HW,

There are some green-gram cultivars which have

‘PDM 54’ - one HW, ‘WBM 04-5’ (‘Sukumar’) -

dense foliage, making them able to compete with

one HW. These treatments were assigned in a

weeds and to prevent yield reduction at minimum

randomized block design with three replications.

extent. Besides, there are some cultivars which may

The crop was fertilized with a basal dose of 20 kg

have allelopathic effect on weeds with which they

N, 40 kg P ₂ O ₅ and 40 kg K ₂ O/ha. Seeds of different

can compete with weeds and do not allow them to

cultivars were sown in lines at a row spacing of 25

grow much in their vicinity. In this perspective, the

cm and plant spacing of 10 cm with a seeding depth

present experiment was carried out in lateritic belt

of 5-6 cm. As per the requirement of the crop, two

of West Bengal to screen out the weed competitive

irrigations were applied, considering the occurrence

green-gram cultivars during summer season.

of rainfall. The crop was irrigated by border strip

method. Population of different categories of weeds

Materials and Methods

at 15, 30 and 45 DAS was recorded by placing the

A field experiment was conducted in two consecutive

quadrat of 50 cm × 50 cm at pre-determined locations

summer seasons of 2008 and 2009 at Agricultural

in the sampling area. The values were converted to

Farm, Institute of Agriculture, Visva-Bharati,

number/m 2 . Grasses, broadleaved and sedges were

Sriniketan, Birbhum, West Bengal, situated at 23°39 /

counted separately and their sum was used to obtain

N latitude and 87°42 / E longitude with an altitude

total weed population. The weed samples for dry

of 58.9 m above mean sea level. The experimental

weight were collected from the area used for weed

site was situated in sub-humid sub-tropical lateritic

count on the same dates (15, 30 and 45 DAS).

belt of the state. Mean maximum temperature

Results and Discussion

ranged from 31.98 to 37.33°C during crop season

(March-May) while mean minimum temperature

Weed Flora

varied from 18.21to 25.56°C. The prevailing climatic

condition in the season was more or less congenial

The experimental plots were infested with sixteen

for the growth and development of green-gram. The

different weed species under three categories and

relative humidity during crop growing period varied

nine families. Digitaria sanguinalis, Cynodon dactylon,

from 81.86 to 95.00%, while the long term average

Dactyloctenium aegyptium, Echinochloa colona , self-

of relative humidity varied from 55.75 to 71.14%.

sown rice (grasses); Cyperus rotundus, C. iria , C.

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