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Genomics and Applied Biology 2015, Vol. 6, No. 3, 1-14
http://gab.biopublisher.ca
3
weed free treatment recorded maximum plant height
and number of leaves plant
-1
. Vora and Mehta (1999)
indicated that maximum number of leaves plant
-1
and
neck thickness was recorded under weed free check in
garlic. In turmeric, the maximum number of plant
height, number of leaves plant
-1
, number of tillers
plant
-1
, dry matter production, leaf area and LAI were
observed in weed free check plots due to reduction in
weed population as noticed by Mannikeri (2006) and
Babu (2008). According to Kaur
et al
. (2008),
unweeded control recorded lesser leaf area index than
all other herbicide treatments in turmeric.
Pre-emergence application of pendimethalin 1.0 kg
ha
-1
recorded higher LAI, LAD, CGR and NAR in
turmeric (Channappagoudar
et al
., 2013).
Yield and yield components
Yield attributes like bulb diameter, number of cloves
plant
-1
, 100 cloves weight, bulb yield plant
-1
and total
bulb yield of garlic were most favourable under weed
free check (Vora and Mehta, 1999). According to
Ramachandra Prasad (2000), uncontrolled weeds
reduced the bulb yield by 75 per cent due to severe
weed competition, particularly due to the presence of
grasses and broad leaved weeds as weed competition
could lower the bulb diameter and bulb weight
considerably in onion. Kaur
et al
. (2008) found that
uncontrolled weed growth resulted in 63.9 per cent
reduction in average rhizome yield of turmeric.
Kavaliauskaite (2009) noticed that weed competition
throughout the crop period caused 82.2 per cent
reduction in bulb yield of onion.
Unweeded check reduced the rhizome yield by 80 per
cent due to severe weed competition, particularly due
to the presence of grasses and broad leaved weeds as
weed competition could lower the number of rhizome
plant
-1
and rhizome weight considerably in turmeric
(Ratnam
et al
., 2012).
Nutrient depletion by weeds
The minimum N, P and K removal (7.45, 0.62, 8.00
kg ha
-1
, respectively) by weeds was observed when
oxyfluorfen at 0.25 kg ha
-1
was supplemented with
hand weeding at 40 DAT followed with the
application of oxyfluorfen at 0.37 kg ha
-1
in onion
(Nandal and Ravinder Singh, 2002). Unweeded check
registered higher nutrient removal of weeds when
compared to herbicide applied plots as reported by
Kumar
et al
. (2004) in groundnut. Kaur
et al
. (2008)
suggested that unweeded control removed 103.5, 19.7
and 170.4 kg N, P K ha
-1
in turmeric. Tuti and Das
(2011) observed that weedy check resulted in higher
removal of N, P and K by weeds. The lowest N, P and
K removal by weeds was observed with
pre-emergence application of metribuzin at 0.5 kg ha
-1
in soybean.
Weed Management Methods
Weed control aims at limiting the growing of
unwanted plants both in space and time, without any
attempt to eliminate the same from the field
environment. Minimizing the weed infestation for
attaining the remunerative crop yield forms the
primary component of weed management.
Cultural Method
Weed control is one of the most important objectives
of cultural operations. Following proper cultural
operations is more than half the weed control method
envisaged on a farm, which directly includes a healthy
growth of crops and indirectly it maintains a crop
environment that is detrimental to weeds.
Vedprakash
et al
. (2000) observed that bulb yield of
onion showed better performance under herbicides
combined with hand weeding treatment over
herbicides alone owing to effective control of weed
through herbicides during initial stage and later on by
hand weeding. Higher weed control was obtained with
manual weeding throughout the crop season in onion
(Marwat
et al
., 2005, Ghadage
et al
.
,
2006 and Zubiar
et
al
.
,
2009).
Babu (2008) reported that weed free check
treatments registered higher cured rhizome yield
(7.08 t ha
-1
) than all other treatments and was followed
by pendimethalin at 1.5 kg ha
-1
(6.03 t ha
-1
) and 1.0
kg ha
-1
(5.74 t ha
-1
) in turmeric. Maximum bulb size
and yield of onion were recorded in hand weeded
plots followed by pendimethalin as compared to
weedy check as noticed by Hussain
et al
. (2008).
Rahman
et al
. (2011) reported that hand weeding
throughout the growing season controlled all weeds
