International Journal of Horticulture 2015, Vol.5, No.3, 1
-
12
8
Preparation of Buffer solutions
Buffer-A
:
10.8 g of sodium bicarbonate and 21.1 g of
sodium carbonate (monohydrate) dissolved in 2 litres
of distilled water.
Buffer-B
:
0.82 g of sodium acetate and 0.5 ml of
glacial acetic acid dissolved in 1 litre f distilled water.
Instrumental conditions
Instrument
HPLC with DAD (Agilent 1200 series)
Mobile phase
Acetonitrile :Distilled water: Acetic acid
70/ 30 (0.01% H
3
PO
4
)
Flow rate
0.5 µl min
-1
Wave length (nm) 20
Injection volume
20 µl (using auto sampler)
Temperature
Ambient
Column
Eclipse XDB C
18
; 5 cm; 4.6 x 150 mm
Retention time
3.36 min (±0.2 min)
Result and Discussion
Turmeric is a long duration crop. Delayed emergence,
slow initial growth of the crop and ample land space
available due to wider spacing permit more sunlight to
reach the soil resulting in conducive environment for
rapid weed growth and enormous damage to crop
yield. The magnitude of yield loss varies from 30 to
75 per cent, depending upon the growth and
persistence of weed density in the standing turmeric
crop (Krishnamurthy and Ayyaswamy, 2000). The
traditional weeding operation is arduous, time
consuming, back breaking and may not be undertaken
at appropriate time due to non-availability of labours
during peak period. So, it is not possible to control the
weeds timely with the traditional methods like hand
weeding. Chemical weed control is an alternative
practice for the control of weeds. In view of the
importance of chemical weed control in turmeric, field
experiments were carried out during
kharif
2012 at
Agricultural Research Station, Bhavanisagar of Tamil
Nadu Agricultural University, to evaluate the
integrated weed management with pre and post
emergence herbicides in turmeric. The results of the
experimentation are discussed below.
Effect of herbicide residues on soil microorganisms
The data on bacterial, fungal and actinomycetes
population recorded at 3, 15, 25, 50 and 75 DAP are
presented in Table 3, 4 and 5. Soil bacteria, fungi and
actinomycetes population were significantly
influenced by weed control practices during the initial
stages immediately after herbicide spray. In plots that
were not applied with the herbicides (hand weeding
and unweeded check), the microbial population
increased continuously during the course of
observation.
Table 3 Effect of integrated weed management practices in turmeric on soil bacteria (x 10
6
CFU g
-1
) -
kharif
, 2012
Treatment
3 DAP 15 DAP 25 DAP 50 DAP 75 DAP
T
1
PE metribuzin 0.7 kg ha
-1
+ HW on 45 and 75 DAP
35.86
53.53
58.65
63.20
69.52
T
2
PE metribuzin 0.7 kg ha
-1
+ POE fenoxaprop 67 g ha
-1
+ metsulfuron 4 g ha
-1
(Tank mix) on 45 DAP
32.98
52.65
57.16
51.75
66.96
T
3
PE metribuzin 0.7 kg ha
-1
+ straw mulch 10 t ha
-1
on 10 DAP + HW on 75
DAP
32.82
55.80
60.37
66.40
68.40
T
4
PE pendimethalin 1.0 kg ha
-1
+ HW on 45 and 75 DAP
31.14
51.43
56.42
60.91
66.91
T
5
PE pendimethalin 1.0 kg ha
-1
+ POE fenoxaprop 67 g ha
-1
+ metsulfuron 4 g
ha
-1
(Tank mix) on 45 DAP
31.43
51.33
55.93
50.05
63.93
T
6
PE pendimethalin 1.0 kg ha
-1
+ straw mulch 10 t ha
-1
on 10 DAP + HW on 75
DAP
31.44
54.15
60.09
65.64
67.64
T
7
PE atrazine 0.75 kg ha
-1
+ HW on 45 and 75 DAP
34.20
53.54
57.18
61.68
68.68
T
8
PE atrazine 0.75 kg ha
-1
+ POE fenoxaprop 67 g ha
-1
+ metsulfuron 4 g ha
-1
(Tank mix) on 45 DAP
33.83
53.77
57.56
51.97
66.53
T
9
PE atrazine 0.75 kg ha
-1
+ straw mulch 10 t ha
-1
on 10 DAP + HW on 75 DAP
33.94
55.67
59.68
65.59
67.59
T
10
PE oxyfluorfen 0.30 kg ha
-1
+ HW on 45 and 75 DAP
33.04
53.94
57.62
62.98
68.98
T
11
PE oxadiargyl 0.25 kg ha
-1
+ HW on 45 and 75 DAP
32.02
53.66
57.67
62.17
68.17
T
12
POE glyphosate 1.03 kg ha
-1
on 25 DAP + HW on 45 and 75 DAP
41.86
59.96
57.17
60.18
69.18
T
13
POE glyphosate 1.54 kg ha
-1
on 25 DAP + HW on 45 and 75 DAP
42.54
60.20
57.96
59.29
69.49
T
14
HW on 25, 45 and 75 DAP
41.95
59.71
64.22
69.24
71.24
T
15
Unweeded check
42.89
60.63
64.99
68.16
70.16
SEd
1.62
2.10
2.25
2.41
2.64
CD (P=0.05 )
3.31
4.30
4.61
4.83
NS
