American Journal of Plant Sciences, 2011, 2, 223-236
doi:10.4236/ajps.2011.22024 Published Online June 2011 (http://www.SciRP.org/journal/ajps)
Leaf Colour Chart vis-a-vis Nitrogen Management
in Different Rice Genotypes
Avijit Sen, Vinod Kumar Srivastava, Manoj Kumar Singh, Ram Kumar Singh, Suneel Kumar
Department of Agronomy, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India.
Received February 16th, 2011; revised April 25th, accepted May 1st, 2011.
ABSTRACT
A field trial comprising 3 rice varieties (NDR-359, Sarju 52, HUBR 2-1) and 4 LCC scores (≤2, ≤3, ≤4, ≤5) a long with
the recommended dose of N was condu cted in a split plot design to calibrate the LCC for nitrog en requirement of rice.
Maximum grain yields of NDR-359, Sarju 52 at LCC ≤ 5 and HUBR 2-1 at LCC ≤ 4 were found to be 47.10, 40.66 and
36.04 q/ha respectively. The critical LCC score for real time nitrogen requirement for NDR 359 and Sarju 52 was found
to be ≤ 5, while for HUBR 2-1 it was ≤ 4. Agronomic and recovery efficiency of nitrog en also followed the same trend.
In the functional relationship between SPAD value and LCC score, while it was linear in NDR-359 and Sarju 52, for
HUBR 2-1 it was quadratic. Further a positive correlation between SPAD values and LCC score was observed in all
the 3 varieties.
Keywords: Leaf Colour Chart (LCC), Nitrogen, Rice
1. Introduction
Rice is the most important source of staple food in India
occupying 44.6 Mha of land and producing 91.04 Mt of
grain with a productivity of 2.04 t/ha [1]. Every third
person on the earth eats rice everyday in one form or the
other and 90% of the total rice produced is consumed in
Asian countries. However, India’s productivity is very
low in comparison to other major rice growing countries
in the world. Among various reasons for this low produc-
tivity, inefficient utilization of nitrogen in considered to
be the most critical one [2]. On the recent world-wide
evaluation of fertilizer, its recovery efficiency has been
found to be around 30% in rice [3]. It has been observed
that more than 60% of applied nitrogen is lost due to lack
of synchronization between the nitrogen demand and
nitrogen supply [4]. Farmers generally apply nitrogen
fertilizer in fixed time recommended N split schedule [5]
in 1:2:1 or 2:1:1 ratio at basal, maximum tillering and
panicle initiation stages respectively, without taking into
account whether the plant really requires N at that time
which may lead to loss or may not be found adequate
enough to synchronize nitrogen supply with actual crop
nitrogen demand [6].
The optimum use of N can be achieved by matching N
supply with crop demand [7]. A simple and quick
method for estimating plant N demand is LCC i.e. leaf
colour chart [8] and SPAD (chlorophyll meter) readings
which can estimate leaf chlorophyll content in a nonde-
structive manner [9], thereby providing an indirect as-
sessment of leaf N status [10]. LCC is easy to use and is
an inexpensive diagnostic tool for monitoring the relative
greenness of a rice leaf as an indicator for the plant N
status and can be used as an alternative to chlorophyll
meter [11]. It offers substantial opportunities to farmers
for detection of time and amount of N to be applied (on
demand) for efficient N use and high rice yield. Thus
LCC becomes useful in avoiding under or above fertili-
zation besides maintaining the appropriate time [12]. Use
of LCC for N management has consistently increased
grain yield and profit in comparison to the farmers’ fer-
tilizer practice in Bangladesh [13-15]. However, critical
LCC values vary considerably among different rice
genotypes having different genetic background, plant
type and leaf colour [16] and this critical colour shade on
the LCC needs to be determined to guide N application
[7]. Keeping this in view the following field trial was
conducted to determine the critical threshold LCC values
for different rice genotypes on the basis of growth, yield,
agronomic and recovery efficiency of N.
2. Materials and Methods
A field trial was conducted during the two consecutive

Leaf Colour Chart vis-a-vis Nitrogen Management in Different Rice Genotypes 224
kharif (rainy) seasons of 2005 and 2006 in the Agricul-
tural Research Farm of the Institute at Varanasi (25°18′N
latitude, 88°3′E longitude and at an altitude of 128.90 m
above mean sea level) situated in the Indo-Gangetic plain
regions of the eastern part of Uttar Pradesh. The climate
of Varanasi is semiarid subtropical with dry hot summer
and cold winter. The average annual rainfall is 1150 mm,
major part of which is received during the later part of
June to mid September. The soil of the experimental site
was sandy clay loam in texture, deep flat, slightly alka-
line in reaction (pH 7.3), well drained and moderately
fertile being low in available nitrogen (208.00 kg/ha) and
phosphate (15.20 kg/ha) and medium in available potas-
sium (231.40 kg/ha). The organic carbon content was
0.43% (Table 1).
The experiment was laid out in a split plot design with
four replications. Three rice genotypes, NDR 359 (a me-
dium duration high yielding variety released from
NDUAT, Faizabad with a yield potential of 4 - 5 t/ha),
Sarju 52 (a 130 - 135 days duration variety having a yield
potential of 5.0 - 5.5 t/ha with long, bold grain) and
HUBR 2-1 (an aromatic rice genotype of 135 - 140 days
duration with relatively thinner leaf developed and re-
leased by Banaras Hindu University with an average
yield of 4.0 - 4.5 t/ha) were grown in the main plots
while the five fertilizer N (as urea) management treat-
ments were allotted to sub-plots. In all the varieties the
LCC scores of <2, ≤3, ≤4 and ≤5 were compared with
fixed time recommended N rate of 120 kg/ha. In the
recommended N rate treatment, nitrogen was applied in
1:2:1 ratio at the time of sowing, maximum tillering and
panicle initiation stages respectively. A uniform dose of
phosphorous and potassium @ 60 kg/ha each and Zn @ 5
kg/ha were applied to all the plots as basal.
2.1. Crop Raising
The experimental field was prepared by puddling twice
with disc harrow and one with cultivator and each
ploughing was followed by planking. After preparing the
field 30 days old seedlings were transplanted on 5th July,
2005 and 10th July 2006 at a spacing of 20 × 15 cm @
3/4 seedlings/hill. After the establishment of seedlings a
constant water level of 5 ± 2 cm was maintained during
the entire crop growth period till early dough stage. For
the management of weeds two hand weeding were done
at 25 and 45 days after transplanting (DAT) respectively.
The crop was harvested manually at maturity at ground
level on 12th October, 2005 and 14th October, 2006 re-
spectively. Grain (at 13% moisture content) and straw
yield on sun dry weight basis were reported in q/ha.
2.2. Leaf Colour Chart
The LCC developed by the Directorate of Rice Research,
Hyderabad, India with seven green shades ranging from
yellowish green to dark green was used in the trial. LCC
readings were taken at 4 days interval starting from 10
DAT till 50% flowering. 10 disease free hills were se-
lected at random from the sampling area in each plot.
From each hill topmost fully expanded leaf was selected
and LCC readings were taken by placing the middle part
of the leaf on the chart and the leaf colour was observed
by keeping the sun blocked by body as sun light affects
leaf colour reading. Whenever the green colour of more
than 5 out of 10 leaves were observed equal to or below a
set critical limit of LCC score, nitrogen was applied @
20 kg/ha to all the three varieties. For all the varieties the
final split application of N was completed by 61/62 days
after transplanting coinciding with the heading stage. A
basal application of 30 kg/N ha was made in all the cases
as per prevalent package of practices of this area (Table 2).
The SPAD reading of the same leaf used for LCC meas-
urement was also taken at three stages on 30, 60 and 90
DAT. The chlorophyll meter (SPAD—502, Minolta,
Ramsey, NJ) or SPAD (Soil Plant Analysis Development)
Table 1. Physical and chemical properties of soil of the experimental site.
Soil Particular Value
Parameters 2005 2006
Physical
Bulk density (g·cc–1)
True density (g·cc–1)
Pore space (%)
WHC (cm)
1.46
2.63
45.50
35.71
1.48
2.65
44.50
34.84
Sand (%)
Silt (%)
Clay (%)
Texture
48.84
29.01
22.41
Sandy Clay Loam
49.10
28.75
22.29
Sandy Clay Loam
Chemical
pH (1:2.5 soil water suspension)
EC (1:2.5 soil water suspension)
Organic carbon (%)
Available N (kg·ha–1)
Available P
(
k
g
·ha–1
)
7.32
0.14
0.42
209.10
15.70
7.30
0.15
0.43
208.00
15.23

Leaf Colour Chart vis-a-vis Nitrogen Management in Different Rice Genotypes 225
Table 2. Treatment used in rice (a basal dose of 30 kg·N·ha–1 was applied to all the treatments).
Treatment details Number of
splits Total N applied (kg·ha–1 ) Time of N application (DAT)
Variety × N management 2005 2006 2005 2006 2005 2006
NDR-359
Recommended dose of N
20 kg·N·ha–1 of LCC < 2
20 kg·N·ha–1 of LCC < 3
20 kg·N·ha–1 of LCC < 4
20 kg·N·ha–1 of LCC < 5
Sarju 52
Recommended dose of N
20 kg·N·ha–1 of LCC < 2
20 kg·N·ha–1 of LCC < 3
20 kg·N·ha–1 of LCC < 4
20 kg·N·ha–1 of LCC < 5
HUBR 2-1
Recommended dose of N
20 kg·N·ha–1 of LCC < 2
20 kg·N·ha–1 of LCC < 3
20 kg·N·ha–1 of LCC < 4
20 kg·N·ha–1 of LCC < 5
3
4
4
5
4
3
4
4
5
5
3
4
4
5
6
3
3
3
4
4
3
3
3
4
4
3
3
3
4
5
30 + 60 + 30 = 120
30 + 20 + 20 + 20 = 90
30 + 20 + 20 + 20 = 90
30 + 20 + 20 + 20 + 20 = 110
30 + 20 + 20 + 20 + 20 = 110
30 + 60 + 30 = 120
30 + 20 + 20 + 20 = 90
30 + 20 + 20 + 20 = 90
30 + 20 + 20 + 20 + 20 = 110
30 + 20 + 20 + 20 + 20 = 110
30 + 60 + 30 = 120
30 + 20 + 20 + 20 = 90
30 + 20 + 20 + 20 = 90
30 + 20 + 20 + 20 + 20 = 110
30 + 20 + 20 + 20 + 20 + 20 = 130
30 + 60 + 30 = 120
30 + 20 + 20 = 70
30 + 20 + 20 = 70
30 + 20 + 20 + 20 = 90
30 + 20 + 20 + 20 = 90
30 + 60 + 30 = 120
30 + 20 + 20 = 70
30 + 20 + 20 = 70
30 + 20 + 20 + 20 = 90
30 + 20 + 20 + 20 = 90
30 + 60 + 30 = 120
30 + 20 + 20 = 70
30 + 20 + 20 = 70
30 + 20 + 20 + 20 = 90
30 + 20 + 20 + 20 + 20 = 110
0, 31, 62
0, 31
0, 25, 47, 62
0, 18, 38, 48, 61
0, 16, 30, 45, 61
0, 30, 60
0, 30, 45, 58
0, 25, 44, 55
0, 18, 35, 47, 61
0, 17, 35, 43, 60
0, 30, 60
0, 30, 43, 58
0, 27, 40, 56
0, 18, 35, 47, 62
0, 14, 27, 40, 50, 61
0, 31, 62
0, 31, 53
0, 28, 51
0, 20, 41, 63
0, 17, 38, 60
0, 30, 60
0, 30, 52
0, 29, 50
0, 20, 42, 62
0, 18, 39, 60
0, 30, 60
0, 31, 52
0, 29, 51
0, 20, 40, 60
0, 19, 36,49, 61
meter is a convenient and reliable tool for in situ chloro-
phyll measurement of plant [17,18] and has been used for
different crops including rice [8]. Leaf area was calcu-
lated in situ by measuring the leaf blade length (l) and
width (w) at three stages by the following formula [19].
Leaf area = k × l × w
with k being the “adjustment factor”, the value of which
was 0.75.
Dry weight of the crop was determined after oven
drying it at 65˚C ± to constant weight. Further grain and
straw samples collected from each plot were dried at 70˚C
in an oven and grounded in the iron grinder. These sam-
ples were digested in sulfuric acid (H2SO4) and analyzed
for their total N content by the Kjeldahl method [20].
Efficiency studies of nitrogen were made as per the
following formula given by [21]. In the recovery effi-
ciency studies since the nutrient contained in the har-
vested portion of the crop (only the above ground portion)
was considered it was termed as nutrient removed instead
of nutrient uptake [22].
Agronomic efficiency (increase in grain yield in kg/kg
N applied through LCC)
n
Grain yield in LCC N fertilized plitgrain yield in recommended N fertilized plot
AE Quantily of N fertilizer applied in LCC N fertilized plot


Recovery efficiency REn (%)
n
RE
Total N removed (kgha) in LCC N fertilized plotTotal N removed (kgha) in recommended N fertilized plot100
Quantily of N fertilizer applied in LCC N fertilized plot


Analyses of the data were done as per the methodol-
ogy of Gomez and Gomez [23]. Functional relationships
between LCC score and chlorophyll content (SPAD)
were worked out using MS Excel (2003) and the ac-
cepted significance level was 0.05.
3. Results and Discussion
For all the three varieties total nitrogen applied with LCC
≤ 2 and ≤ 3 were 90 and 70 kg/ha , while it was 110 and
90 kg/ha with LCC ≤ 4 and ≤ 5 in first and second year
respectively (Table 2). However, under recommended
dose of nitrogen it was 120 kg/ha applied in 3 splits. For
all the varieties the final split application was completed
by 61/62 days after transplanting coinciding with the
heading stage. A basal application of 30 kg·N/ha was
applied under all the treatments as per prevalent package

Leaf Colour Chart vis-a-vis Nitrogen Management in Different Rice Genotypes 226
of practices of this area.
Among the varieties NDR 359 produced leaves with
maximum area/ hill followed by Sarju 52 and HUBR 2-1
respectively and leaf area of NDR 359 was found to be
significantly superior to HUBR 2-1 (Table 3). In the leaf
colour chart score LCC ≤ 5 for NDR 359 and Sarju 52
showed significantly higher leaf area than other scores
and recommended dose at all the stages of growth.
However, in case of HUBR 2-1 LCC ≤ 4 and ≤ 5 re-
mained statistically at par with each other with maximum
leaf area.
Leaf area index (LAI) was found to increase up to 60
DAT after which it decreased with the passage of time
(Table 4). Leaf area index for the varieties and LCC
scores were found in the order of NDR 359 > Sarju 52 >
HUBR 2-1 and LCC 5 > 4 > 3 > 2 > recommended dose
of N. Further, variety was found to interact significantly
with LCC score in influencing the LAI. At all the stages
of growth the highest LAI was recorded in NDR 359 at
LCC ≤ 5.
No significant effect in chlorophyll content of leaves
due to varieties was observed at any stage of the growth
(Table 5). However, significant differences were ob-
served due to LCC scores at all the stages of growth.
There was a gradual increase in the chlorophyll content
with the increase in LCC score up to ≤ 5 for NDR 359
and Sarju 52 while for HUBR 2-1 the increase was up to
≤ 4 only beyond which it declined. Significant differ-
ences in dry weight of hill were observed due to both the
variables at all the stages of growth during both the years
(Table 6). Among the varieties NDR 359 registered
maximum dry weight followed by Sarju 52 and HUBR
2-1 while in case of LCC scores the highest dry weight
was found with score ≤ 5 for NDR 359 and Sarju 52 and
≤ 4 for HUBR 2-1. In all the cases the lowest dry weight
was found with recommended dose of N application.
Similar trend was observed in al the reproductive char-
acters of rice also (Tables 7 and 8). Number of pani-
cles/m, panicle length, panicle weight, filled spikelets/
panicle, grain filling percentage, test weight, grain and
straw yields were found to be higher with NDR 359
among the varieties and with LCC ≤ 5 among the LCC
scores except in HUBR 2-1 where LCC ≤ 4 out yielded
LCC ≤ 5. In the nitrogen removal studies it was observed
that maximum amount of N was removed by NDR 359
which was significantly superior to other two varieties
during both the years (Table 9). Among the LCC scores
while N removal from soil was highest at ≤ 5 for both
NDR 359 and Sarju 52, it was highest at LCC ≤ 4 for
HUBR 2-1. Further for agronomic and recovery efficiency
of N it was found to be highest at LCC ≤ 5 for NDR 359
and Sarju 52 but at LCC ≤ 4 for HUBR 2-1 (Table 10).
Table 3. Effect of treatments on the leaf area (cm2·hill−1) of rice.
30 DAT 60 DAT 90 DAT
N-management 2005 2006 2005 2006 2005 2006
NDR-359
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
17.07
18.71
18.89
22.11
25.43
20.44
16.71
18.25
18.43
21.79
25.08
20.05
48.89
50.43
50.81
53.92
57.23
52.30
49.71
51.25
51.43
54.79
58.08
53.05
44.43
45.11
46.09
47.34
49.67
46.53
43.71
44.25
45.43
46.79
48.80
45.08
Sarju-52
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
15.52
18.22
18.38
19.11
22.86
18.82
15.01
17.75
17.98
18.70
22.53
18.40
47.32
58.02
51.77
51.07
54.43
50.92
48.01
50.75
52.23
51.70
55.73
51.64
41.05
43.72
44.02
45.42
48.13
44.47
40.19
42.92
43.15
44.75
47.58
43.71
HUBR 2-1
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
14.04
16.63
18.29
19.21
19.73
17.58
13.46
16.10
17.81
18.86
19.10
17.06
45.83
46.04
48.43
50.74
51.63
48.53
46.46
46.60
49.06
51.86
52.10
49.22
39.34
41.79
43.51
44.33
44.91
42.78
38.46
41.10
42.81
43.86
44.10
42.06
SEdm ± for variety
CD (P = 0.05)
SEdm ± for LCC
CD (P = 0.05)
0.79
1.94
0.65
1.32
0.90
2.21
0.78
1.59
1.12
2.74
0.97
1.97
1.03
2.53
0.81
1.65
1.21
2.96
1.03
2.09
1.01
2.48
0.83
1.69

Leaf Colour Chart vis-a-vis Nitrogen Management in Different Rice Genotypes 227
Table 4. Effect of treatments on leaf area index (LAI) of rice.
30 DAT 60 DAT 90 DAT
N-management 2005 2006 2005 2006 2005 2006
NDR-359
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
1.41
1.63
1.72
1.93
2.74
1.89
1.33
1.58
1.64
1.81
2.61
1.79
4.89
5.67
5.72
6.22
7.93
6.09
4.74
5.45
5.51
6.01
7.77
5.91
4.02
4.55
4.72
4.89
6.43
4.92
3.89
4.33
4.57
4.77
6.28
4.77
Sarju-52
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
1.11
1.34
1.30
1.72
2.04
1.50
1.05
1.27
1.21
1.50
1.92
1.39
4.31
4.62
5.01
5.41
6.37
5.14
4.02
4.47
4.85
5.20
6.22
4.95
3.32
3.57
3.62
3.81
4.57
3.78
3.01
3.30
3.32
3.66
4.41
3.54
HUBR 2-1
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
1.01
1.23
1.34
1.41
1.52
1.30
0.84
1.04
1.11
1.23
1.37
1.12
3.51
4.06
4.47
4.26
4.92
4.24
3.38
3.88
4.30
4.11
4.70
4.08
2.78
3.02
3.18
3.42
3.69
3.22
2.59
2.81
3.09
3.24
3.57
3.06
SEdm ± for variety
CD (P = 0.05)
SEdm ± for LCC
CD (P = 0.05)
SEdm ± V x N
CD (P = 0.05)
0.10
0.24
0.09
0.18
0.17
0.35
0.06
0.15
0.07
0.14
0.12
0.24
0.28
0.69
0.21
0.43
0.39
0.79
0.22
0.54
0.20
0.41
0.34
0.69
0.15
0.38
0.20
0.41
0.32
0.65
0.09
0.22
0.14
0.29
0.24
0.49
Table 5. Effect of treatments on chlorophyll content of leaf (SPAD).
30 DAT 60 DAT 90 DAT
N-management 2005 2006 2005 2006 2005 2006
NDR-359
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
30.90
31.61
32.46
33.43
35.56
32.79
29.95
30.60
31.65
32.40
34.68
31.85
31.67
32.29
33.45
36.06
36.38
33.97
30.70
31.35
32.40
35.15
35.43
33.00
25.87
29.78
30.01
30.66
30.68
30.20
24.90
28.85
29.08
29.75
29.71
29.46
Sarju-52
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
27.68
32.01
33.66
33.97
34.68
32.40
26.65
31.18
32.75
33.00
33.75
31.46
28.35
31.69
32.85
34.61
35.45
32.59
27.40
30.75
31.93
33.50
34.50
31.61
26.22
28.78
30.97
31.81
32.86
30.13
25.28
27.88
30.08
31.00
31.93
29.23
HUBR 2-1
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
27.81
28.81
29.77
32.56
31.08
29.67
26.90
27.20
27.85
31.68
30.20
28.76
31.26
31.30
31.98
33.54
32.33
32.08
30.25
30.28
30.95
32.43
31.25
31.03
22.83
28.57
29.71
31.06
30.77
29.79
23.95
27.65
28.60
30.10
29.83
28.83
SEdm ± for variety
CD (P = 0.05)
SEdm ± for LCC
CD (P = 0.05)
1.46
NS
1.01
2.05
1.54
NS
1.20
2.44
1.56
NS
1.08
2.20
1.62
NS
1.16
2.36
0.62
NS
0.54
1.10
0.70
NS
0.65
1.32

Leaf Colour Chart vis-a-vis Nitrogen Management in Different Rice Genotypes 228
The total leaf area per unit ground area known as LAI
increases according to the compound interest law,
reaches its maximum value around heading and de-
creases thereafter with the senescence of lower leaves
[24]. LAI being directly correlated to leaf area [19] was
found to increase up to 60 DAT along with the growth of
the leaf and decreased subsequently due to withering of
leaves. It is a well known fact that among the various
factors responsible for increase in LAI, tiller number and
size of leaves are the most important ones [25] and both
these components in turn are greatly influenced by the
availability of nitrogen in soil [24]. Higher leaf area and
LAI of rice under LCC governed plots in comparison to
the fixed time recommended split application of nitrogen
clearly indicated that nitrogen availability to rice was
much more and assured in the plots where nitrogen was
applied as per LCC scores. Further LCC score and chlo-
rophyll content (SPAD) of all the varieties (Table 11)
showed a positive correlation (although not significant in
all the cases) ranging from (r = 0.631 to 0.997). Since
chlorophyll content depicts the nitrogen status of the
plants [2], it indicated that plants under recommended
split of nitrogen suffered from nitrogen deficiency at all
the stages [10].
The relationship between SPAD values and LCC
scores was found to be linear (Figures 1-12) for NDR
359 and Sarju 52, while in HUBR 2-1 it was quadratic at
all the stages (Figures 13-18). Overall the SPAD value
in case of HUBR 2-1 was found a little less which was
most probably due to lesser leaf thickness. Yang et al. [26]
also reported from Philippines that leaf thickness directly
affected the chlorophyll content and corresponding LCC
score in rice. The present results indicated that LCC for
real time N management could not be replaced by SPAD
meter for all the rice varieties. Dry matter production is
dependent upon the plant’s metabolic activities and its
corresponding growth. With higher leaf area and chloro-
phyll content the plant could exhibit higher photosyn-
thetic activities which ultimately led to greater dry matter
production. In all the three varieties N applied through
LCC 5 and 4 produced higher plant dry weight. Higher
chlorophyll content can lead to higher photosynthetic rate
[27] by virtue of higher leaf N concentration [10],
thereby resulting in greater biomass production [28].
Higher efficiency of N applied through LCC was further
reflected in the number of filled and unfilled spikelets/
panicle produced by the crop. Significant differences in
the filled and unfilled spikelets number between LCC
and recommended dose and split of N application were
observed during both the years. Higher leaf area and
chlorophyll content under LCC treatment might have led
to higher grain filling percentage. Total leaf area coupled
Table 6. Effect of treatments on dry weight of plant (g·hill−1).
30 DAT 60 DAT 90 DAT Harvest
N-management
2005 2006 2005 2006 2005 2006 2005 2006
NDR-359
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
6.16
6.28
6.89
7.02
7.52
6.77
5.63
5.87
6.34
6.50
7.11
6.29
14.07
13.98
14.79
14.98
15.07
14.58
13.30
13.37
13.84
14.00
14.61
13.79
25.33
25.23
25.58
26.13
26.43
25.74
24.13
24.37
24.84
25.00
25.61
24.79
31.22
32.33
34.71
35.27
36.02
33.91
30.63
31.41
33.88
34.32
35.14
32.974
Sarju-52
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
4.83
5.19
5.38
5.97
6.49
5.57
4.20
4.40
4.65
5.42
5.84
4.90
10.88
11.18
11.49
12.07
12.03
11.53
10.20
10.40
10.59
10.48
11.90
10.92
21.44
22.08
22.39
23.24
22.76
22.38
20.20
21.40
21.64
22.42
21.84
23.90
28.11
30.92
31.78
32.28
32.57
31.13
27.40
30.15
31.03
31.39
31.88
30.37
HUBR 2-1
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
4.54
4.78
4.99
5.76
5.50
5.11
3.99
4.03
4.32
4.96
4.60
4.38
10.52
10.79
10.34
11.64
11.38
10.93
9.49
9.53
9.77
10.83
10.48
10.02
19.22
19.39
19.50
20.07
19.82
19.60
18.49
18.53
18.82
19.46
19.10
18.88
26.17
27.34
28.33
29.31
29.22
28.07
25.99
26.74
27.45
28.91
28.22
27.46
SEdm ± for variety
CD (P = 0.05)
SEdm ± for LCC
CD (P = 0.05)
0.65
1.59
0.33
0.97
0.74
1.81
0.38
0.65
0.39
0.95
0.45
0.91
0.58
1.42
0.39
0.69
0.31
0.76
0.52
1.06
0.47
1.14
0.48
0.97
1.28
3.13
0.88
1.79
1.49
3.65
0.81
1.64

Leaf Colour Chart vis-a-vis Nitrogen Management in Different Rice Genotypes 229
Table 7. Effect of treatments on the yield attributing characters.
Panicles/m2 Panicle length (cm) Panicle wt (g) Test wt (g)
N-management 2005 2006 2005 2006 2005 2006 2005 2006
NDR-359
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
256.55
268.72
274.13
278.84
283.23
272.30
254.50
265.88
271.00
275.63
279.11
269.22
25.45
27.22
27.75
27.66
27.03
27.02
24.36
26.30
26.81
26.71
26.14
26.06
3.21
3.34
3.49
3.67
3.75
3.49
3.01
3.11
3.29
3.48
3.54
3.28
22.81
26.03
26.99
28.85
29.92
26.92
20.75
24.22
25.38
27.57
28.75
25.33
Sarju-52
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
250.33
251.85
264.15
268.78
270.33
261.09
247.40
248.75
261.63
263.63
265.25
257.33
22.75
25.23
25.41
26.31
26.52
25.24
21.90
24.34
24.44
25.44
25.55
24.39
2.99
3.16
3.18
3.51
3.59
3.29
2.87
3.03
3.05
3.38
3.44
3.15
21.34
24.53
25.04
27.62
27.89
25.28
19.25
22.70
23.35
26.55
26.55
23.40
HUBR 2-1
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
240.88
249.38
256.43
265.12
263.48
255.06
237.50
246.50
251.00
259.63
258.13
250.55
22.38
24.90
25.22
26.56
26.23
24.86
21.40
23.98
24.26
25.70
25.32
24.13
1.83
2.25
2.36
2.51
2.45
2.28
1.71
2.11
2.28
2.34
2.31
2.15
19.32
21.30
22.52
24.62
24.26
22.40
17.25
19.10
20.00
22.50
22.15
20.20
SEdm ± for variety
CD (P = 0.05)
SEdm ± for LCC
CD (P = 0.05)
6.03
14.76
6.83
13.89
5.51
13.48
6.26
12.73
0.72
1.76
0.54
1.10
0.57
1.40
0.49
1.00
0.18
0.44
0.20
0.41
0.15
0.37
0.17
0.35
0.59
1.44
0.29
0.59
0.44
0.84
0.08
0.16
Table 8. Effect of treatments on the yield and yield attributes.
Filled
spikelets/panicle
Unfilled
spikelets/panicle Grain yield (q/ha) Straw yield (q/ha) Harvest index (%)
N-management
2005 2006 2005 2006 2005 2006 2005 2006 2005 2006
NDR-359
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
128.11
136.43
142.32
145.61
146.01
139.70
123.26
131.58
137.58
140.05
140.64
134.65
32.63
24.66
21.62
20.32
18.63
23.57
27.70
19.72
16.57
15.46
13.70
18.63
38.03
40.02
41.98
46.12
48.33
42.90
36.00
37.13
39.39
43.99
45.87
40.47
57.11
58.09
59.22
64.31
65.35
60.82
54.99
55.93
57.18
62.19
63.31
58.72
39.97
40.79
41.48
41.76
42.51
41.30
39.47
39.90
40.79
41.43
42.01
39.47
Sarju-52
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
128.11
137.62
138.63
139.85
145.21
137.88
123.77
132.74
133.77
134.92
140.47
133.05
29.15
27.63
27.32
26.32
24.29
26.94
24.22
22.72
22.49
21.35
19.35
22.02
32.31
34.03
37.41
40.29
42.49
37.31
29.42
31.17
34.60
37.42
38.82
34.29
50.31
51.18
54.97
58.19
59.92
54.91
47.28
50.38
52.92
56.21
57.81
52.92
39.11
39.94
40.50
40.91
41.49
40.39
37.56
38.52
39.20
39.93
40.15
39.07
HUBR 2-1
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
102.39
113.49
122.09
125.37
123.61
117.39
97.75
108.62
117.17
120.00
118.55
112.41
45.19
36.11
36.97
29.17
30.39
35.41
40.50
31.04
31.02
24.25
25.48
30.45
28.29
31.33
33.01
37.29
35.51
33.09
25.38
28.48
30.08
34.78
32.43
30.23
46.21
49.25
50.72
55.32
53.17
50.93
44.18
47.28
48.88
53.58
51.23
49.03
37.97
38.88
39.42
40.27
40.04
39.32
30.47
36.55
37.305
38.68
37.56
36.06
SEdm ± for variety
CD (P = 0.05)
SEdm ± for LCC
CD (P = 0.05)
4.01
9.81
3.41
6.93
3.82
9.35
3.33
6.75
2.01
4.92
1.63
3.31
2.11
3.15
1.78
3.61
0.67
1.64
0.58
1.18
0.55
1.34
0.45
0.89
0.71
1.74
0.56
1.14
0.60
1.48
0.49
0.98
0.35
0.86
0.28
0.57
0.26
0.64
0.22
0.46

Leaf Colour Chart vis-a-vis Nitrogen Management in Different Rice Genotypes 230
Table 9. Effect of treatments on removal of nitrogen.
N removed by grain (kg/ha) N removed by straw (kg/ha) Total N removed (kg/ha)
N-management 2005 2006 2005 2006 2005 2006
NDR-359
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
39.03
47.19
48.57
55.33
59.23
49.87
38.16
45.29
47.62
54.43
58.15
48.73
30.63
33.51
35.63
40.47
44.01
36.85
28.83
31.95
33.51
39.03
41.58
34.98
69.52
80.62
84.25
95.69
103.16
86.70
66.90
77.20
81.05
93.44
99.79
83.71
Sarju-52
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
36.46
39.11
42.56
47.25
51.52
43.38
35.31
37.75
40.43
44.26
50.05
41.56
27.83
29.01
31.16
35.43
39.12
32.51
25.77
27.86
29.99
33.58
36.20
30.68
64.23
68.17
73.62
82.59
90.55
75.83
60.92
65.71
70.37
77.76
86.20
72.24
HUBR 2-1
Recommended dose
LCC < 2
LCC < 3
LCC < 4
LCC < 5
Mean
34.10
36.29
38.52
41.63
40.31
38.17
32.31
34.12
36.33
39.61
37.73
36.02
24.73
26.81
28.12
35.06
32.93
29.53
22.95
25.78
27.16
31.37
29.99
27.45
59.03
62.91
66.73
76.55
73.12
67.70
55.06
59.95
63.55
71.04
67.68
63.46
SEdm ± for varieties
CD (P = 0.05)
SEdm ± for LCC
CD (P = 0.05)
0.91
2.23
1.17
2.38
0.84
2.06
1.02
2.07
0.61
1.49
0.72
1.46
0.58
1.22
0.60
1.22
0.73
1.79
0.98
1.99
0.88
2.15
1.10
2.24
Table 10. Effect of treatments on grain filling percentage, agronomic and recovery efficiency.
Grain filling percentage Agronomic efficiency
(kg grain/kg N applied) Recovery efficiency of Nitrogen (REn) N-management
2005 2006 2005 2006 2005 2006
NDR-359
Recommended dose
LCC< 2
LCC< 3
LCC< 4
LCC< 5
Mean
79.70
84.69
86.81
87.75
88.68
85.53
81.60
86.97
89.25
90.06
91.12
87.80
−
2.21
4.39
7.36
9.36
5.83
−
1.61
4.84
8.88
10.97
6.58
−
12.33
16.37
23.79
30.58
20.77
−
14.71
20.21
29.49
36.54
25.24
Sarju 52
Recommended dose
LCC< 2
LCC< 3
LCC< 4
LCC< 5
Mean
81.46
83.28
83.54
84.16
85.67
83.63
85.39
85.61
86.34
87.89
85.77
−
1.91
5.67
7.26
9.26
6.03
−
2.50
7.40
8.89
10.44
7.31
−
4.38
10.43
16.69
23.93
13.86
−
6.84
13.50
18.71
28.09
16.79
UBR 2-1
Recommended dose
LCC< 2
LCC< 3
LCC< 4
LCC< 5
Mean
69.38
75.86
76.76
81.12
80.27
76.68
70.70
77.77
79.07
83.19
82.31
78.61
−
3.38
5.24
8.18
5.55
5.59
−
4.43
6.71
10.44
6.41
7.00
−
4.31
8.55
15.93
10.84
9.91
−
6.99
12.13
17.76
11.47
12.09
SEdm ± for variety
CD for variety(P = 0.05)
SEdm ± for LCC
CD for LCC (P = 0.05)
−
−
−
−
−
−
−
−
1.12
2.74
1.31
2.66
0.80
1.96
0.88
1.79
−
−
−
−
−
−
−
−

Leaf Colour Chart vis-a-vis Nitrogen Management in Different Rice Genotypes 231
Table 11. Correlation coefficient (r) between chlorophyll content (SPAD) and LCC scores.
NDR 359
30 DAT 60 DAT 90DAT
2005 2006 2005 2006 2005 2006
0.973* 0.969* 0.963* 0.958* 0.946 0.951*
Sarju 52
0.950* 0.951* 0.992** 0.997** 0.975* 0.973*
HUBR 2-1
0.796 0.797 0.640 0.631 0.907 0.914
*
Significant at P = 0.05, **Significant at P = 0.01.
y = 1.282x + 28.778
r = 0.972928
30
31
32
33
34
35
36
37
1.522.533.544.555.
LCC score
Chlorophyll content
5
Y
Linear (Y)
y = 1.488x + 29.337
r = 0.962648
31
32
33
34
35
36
37
38
1.522.533.544.55 5.5
LCC score
Chlorophyll content
Y
Linear ( Y)
Figure 1. NDR-359, 30 DAT, 2005. Figure 3. NDR-359, 60 DAT, 2005.
y = 1.299x + 27.786
r = 0.969151
29.00
30.00
31.00
32.00
33.00
34.00
35.00
36.00
1.522.5 3 3.5 44.5 5 5.5
LCC Score
Chlorophyll content
Y
Linear (Y )
y = 1.499x + 28.336
r = 0.957571425
30.00
31.00
32.00
33.00
34.00
35.00
36.00
37.00
1.5 22.5 3 3.54 4.55 5.5
LCC score
Chlorophyll content
Y
Linear ( Y)
Figure 2. NDR-359, 30 DAT, 2006. Figure 4. NDR-359, 60 DAT, 2006.
with high chlorophyll content at flowering has been re-
ported to affect the amount of photosynthates available to
the panicle [29,30].
During both the years of experimentation significant

Leaf Colour Chart vis-a-vis Nitrogen Management in Different Rice Genotypes 232
y = 0.335x + 29.11
r = 0.945803288
29. 40
29. 60
29. 80
30. 00
30. 20
30. 40
30. 60
30. 80
31. 00
31. 20
1.522.533.5 4 4.5 5 5.5
LCC score
Chlorophyll content
Y
Linear (Y)
Figure 5. NDR-359, 90 DAT, 2005.
y = 0.325x + 28.21
r = 0.92859038
28.60
28.80
29.00
29.20
29.40
29.60
29.80
30.00
30.20
1.5 22.5 33.5 44.55 5.5
LCC scor e
Chlorophyll content
Y
Linear (Y )
Figure 6. NDR-359, 90DAT, 2006.
y = 0.832x + 30.668
r = 0.950202698
31.5
32
32.5
33
33.5
34
34.5
35
35.5
1.52 2.53 3.5 4 4.55 5.5
LCC score
Chlorophyll content
Y
Linear (Y)
Figure 7. Sarju-52, 30DAT, 2005.
y = 0.796x + 29.884
r = 0.951157421
30.50
31.00
31.50
32.00
32.50
33.00
33.50
34.00
34.50
1.522.533.544.555
LCC scor e
Chlorophyll content
.5
Y
Linear (Y)
Figure 8. Sarju-52, 30DAT, 2006.
y = 1.304x + 29.086
r = 0.99180276
30
31
32
33
34
35
36
37
1.522.53 3.5 4 4.5 5 5.5
LCC score
Chloroph yll content
Y
Linear ( Y)
Figure 9. Sarju-52, 60DAT, 2005.
y = 1.282x + 28.183
r = 0.9967197
29.00
30.00
31.00
32.00
33.00
34.00
35.00
36.00
1.522.5 33.5 4 4.5 55.5
LCC score
Chlorophyll content
Y
Linear (Y )
Figure 10. Sarju-52, 60DAT, 2006.

Leaf Colour Chart vis-a-vis Nitrogen Management in Different Rice Genotypes 233
y = 1.308x + 26.527
r = 0.974876896
28.00
29.00
30.00
31.00
32.00
33.00
34.00
1.522.53 3.54 4.55 5.5
LCC scor e
Chlorophyll content
Y
Linear (Y)
Figure 11. Sarju-52, 90DAT, 2005.
y = 1.307x + 25.648
r = 0.972685925
27. 00
28. 00
29. 00
30. 00
31. 00
32. 00
33. 00
34. 00
1.522.53 3.5 4 4.5 5 5.5
LCC score
Chlorophyll content
Y
Linear (Y)
Figure 12. Sarju-52, 90DAT, 2006.
y = -0.61x
2
+ 5. 2 3x + 20. 485
r = 0. 760999
26.5
27
27.5
28
28.5
29
29.5
30
30.5
31
31.5
32
32.5
33
1.522.533.544.555
LCC score
Chlorophyll content
.5
Y
Pol y. ( Y)
y = –0.61x
2
+ 5.23x + 20.485
r = 0.760999
Figure 13. HUBR 2-1, 30DAT, 2005.
y = -0.5325x
2
+ 5.0105x + 18.884
r = 0.796643
25.00
25.50
26.00
26.50
27.00
27.50
28.00
28.50
29.00
29.50
30.00
30.50
31.00
31.50
32.00
32.50
1.522.533.544.555.
LCC score
Chlorophyll content
5
Y
Poly . (Y)
y = –0.5325x
2
+ 5.0105x + 18.884
r = 0.796643
Figure 14. HUBR 2-1, 30DAT, 2006.
y = -0.4725x
2
+ 3.7725x + 25.462
r = 0.639901861
30.00
30.50
31.00
31.50
32.00
32.50
33.00
33.50
34.00
1.5 22.5 3 3.5 4 4.5 55.5
LCC score
Chlorophyll content
Y
Poly. (Y)
y = –0.4725x
2
+ 3.7725x + 25.462
r = 0.639901861
Figure 15. HUBR 2-1, 60DAT, 2005.
y = -0.4625x
2
+ 3.6765x + 24.603
r = 0.63085197
28.50
29.00
29.50
30.00
30.50
31.00
31.50
32.00
32.50
33.00
1.5 2 2.5 33.5 4 4.5 55.5
LCC score
Chlorophyll conten t
Y
Poly . (Y)
y = –0.4625x
2
+ 3.6765x + 24.603
r = 0.63085197
Figure 16. HUBR 2-1, 60DAT, 2006.

Leaf Colour Chart vis-a-vis Nitrogen Management in Different Rice Genotypes 234
y = -0.3575x
2
+ 3.2975x + 23.313
r = 0.906873279
27.00
27.50
28.00
28.50
29.00
29.50
30.00
30.50
31.00
31.50
1.522.533.54 4.555.5
LCC s co r e
Chlorophyll content
Y
Poly. (Y)
y = –0.3575x
2
+ 3.2975x + 23.313
r = 0.906873279
Figure 17. HUBR 2-1, 90DAT, 2005.
y = -0.305x
2
+ 2.939x + 22.876
r = 0.913483028
26.00
26.50
27.00
27.50
28.00
28.50
29.00
29.50
30.00
30.50
1.522.533.544.55 5.5
LCC score
Chlorophyll content
Y
Pol y. ( Y)
y = –0.305x
2
+ 2.939x + 22.876
r = 0.913483028
Figure 18. HUBR 2-1, 90DAT, 2006.
differences in grain yield among the varieties were ob-
served. NDR-359 produced maximum yield followed by
Sarju 52 and HUBR 2-1 respectively. Among the LCC
scores LCC < 5 produced the highest yield followed by
LCC 4, 3 and 2 in NDR-359 and Sarju 52 while in
HUBR 2-1 it was ≤4 followed by 5, 3 and 2 respectively.
In all these cases recommended dose of N registered the
lowest yield although maximum amount of N i.e. 120
kg/ha was applied in this treatment. Corresponding har-
vest index and N removal also showed the same trend.
Higher harvest index in the LCC—aided N management
treatments than the fixed time recommended N applica-
tion suggested that fertilizer N applied on the basis of
need of the plant was better translated into grain yield
[31]. The threshold value of LCC ≤ 5 for NDR 359 and
Sarju 52 and ≤ 4 for HUBR 2-1 recorded the highest ag-
ronomic and recovery efficiency of nitrogen. In all the
three varieties higher threshold value of LCC exhibited
higher grain yield per kg N applied. Overall, application
of N through LCC could register 15.99 and 15.54% for
NDR 359, 19.33 and 20.68% for Sarju 52, 21.19 and
23.89% for HUBR 2-1 higher grain yield than recom-
mended dose and split application of N in 2005 and 2006
respectively.
Nitrogen use efficiency (NUE) is dependent to a large
extent on the synchronization between crop nitrogen de-
mand and the available N supply [31]. Nutrient removal
is a function of climate, soil properties, amount and
method of fertilizer application and the variety of rice [30]
where cultural practices and morphological variations
account for differences in nutrient removal. In addition to
this dry matter production and yield also govern the nu-
trient removal. Quite expectedly higher yield by NDR
359 led to higher N removal which was followed by
Sarju 52 and HUBR 2-1 respectively. Similarly under
LCC score also total N removal was found in the se-
quence of 5 > 4 > 3 > 2 > for NDR 359 and Sarju 52,
while it was 4 > 5 > 3 > 2 > for HUBR 2-1. In all the
cases lowest removal of nitrogen was recorded under the
recommended dose and split of N application. This trend
clearly suggested that the loss of N was maximum under
recommended dose of N application. Yield is correlated
to N requirement and responds positively to solar radia-
tion [32,33] nutrient supply and package of practices [34].
N management strategy should therefore take into ac-
count the crop N requirement and soil N supply. LCC
strategy calibrated with SPAD determines the real time
for efficient management of N [26]. However, for this
critical LCC values are to be determined which may not
be same for all the varieties.
4. Conclusions
Critical or threshold LCC values are known as those that
optimize simultaneously the grain yield and NUE. It has
been reported that higher agronomic efficiency of N with
consistent high grain yield could be regarded as an indi-
cator for efficient N management in rice. On the basis of
higher grain yield along with corresponding higher ag-
ronomic and recovery efficiency and other parameters
LCC < 5 for NDR 359, Sarju 52 and ≤ 4 for HUBR 2-1
were judged to be the critical values for proper N man-
agement.
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