Rice Technology Bulletin

Department of Agriculture
Philippine Rice Research Institute (PhilRice) ISSN 0117-9799 1997 No. 24

COLOR CHART
LEAF
Rice Technology Bulletin Series:

No. 1 Released Rice Varieties (1968-1994)

No. 2 Pagpaparami at Pagpupuro ng Binhi sa
Sariling Bukid
No. 3 Paggawa ng Maligaya Rice Hull Stove
No. 4 PhilRice Micromill
No. 5 PhilRice Flourmill
No. 6 PhilRice Drumseeder
No. 7 PhilRice Rototiller
No. 8 Rice Food Products
No. 9 PhilRice-UAF Batch Dryer
No. 10 Integrated Management of the Malayan Black Bug
No. 11 SG800 Rice Stripper-Harvester
No. 12 Dry Seeded Rice-Based Cropping Technologies
No. 13 Maligaya Rice Hull Stove
No. 14 10 Steps in Compost Production
No. 15 Rice Tungro Virus Disease
No. 16 The Philippine Rice Seed Industry and the
National Rice Seed Production Network
No. 17 10 Hakbang sa Paggawa ng Kompost
No. 18 10 nga Addang ti Panagaramid iti Compost
No. 19 Characteristics of Popular Philippine Rice Varieties
No. 20 Integrated Pest Management of the Rice Black Bug
No. 21 RiceFood Products (revised edition)

Published 1998 by the Philippine Rice Research Institute. Readers are

encouraged to reproduce contents of this bulletin with acknowledgment.
Foreword
In the past, farmers apply fertilizer to their crop at fixed intervals. In rice,
for instance, the total N requirement of the rice crop is applied in three splits:
at basal, before panicle initiation, and at early flowering. Recent scientific
findings, however, show that this “feeding time” is not applicable to all variet-
ies. There are varieties which mature earlier or later. Maturity is also affected
by season and climate. More recent findings indicate that native soil fertility
vary not only by region or province, but even within a field plot. The result is
that farmers have been applying N fertilizer much earlier –– when the plant
does not need it –– or applying much later than when the plant needs it most.
Hence, the crop recovers only 30-50 percent of the fertilizer applied due to
improper time of application and losses through leaching and
volatilization.
Recognizing that fertilizer management is a knowledge-intensive technol-
ogy, the Philippine Rice Research Institute (PhilRice), based in Muñoz,
Nueva Ecija, and the International Rice Research Institute (IRRI) based in
Los Baños, Laguna, designed a simple decision aid tool that will help farmers
visually assess the nitrogen status of the rice plant. The tool is called the Leaf
Color Chart (LCC).
The LCC is handy plastic “ruler” with strips of six shades of green color to
simulate the color of rice leaves under field conditions. The topmost fully
expanded and healthy leaf from a rice plant is placed on top of the leaf color
chart and graded according to the corresponding color strip on the “ruler”.
The result of the grading, taken on a weekly basis, forms the basis of fertilizer
application. Green leaf color intensity can be related to plant nitrogen concen-
tration, requirement and, hence, the time and amount of N fertilizer to apply.
The LCC can generate savings of up to P1,000 per hectare in nitrogen
fertilizer use. It is a cheap, fast, and handy field instrument to measure color
intensity of the green leaf. Knowledge of proper “feeding time and amount”
can increase fertilizer use efficiency, and protect the ground and surface
water from contamination.

SANTIAGO R. OBIEN
Executive Director

1
Basal P and K, and Zn as broadcast
During the final land preparation, incorporate at least 40 kg/ha
phosphorous (3 1/2 bags of solophos or 0-18-0) and 30 kg potassium (1
bag muriate of potash 0-0-60). Two weeks after transplanting or direct
seeding, broadcast 20 kg zinc sulfate per hectare when discoloration of
the older leaves is observed.

When to take first reading

Starting at 14 days after transplanting until the flowering stage, begin to
take weekly readings and apply the needed nitrogen fertilizer. This will
require 8-9 weekly readings depending on the maturity date of the
variety used. For direct seeded rice, start taking readings 21 days after
sowing. Weekly visit to the field allows the farmer to closely observe the
crop’s response to fertilization.

start reading

Germination Seedling Tillering Panicle initiation Heading/Flowering

TILLERING FLOWERING
55-85 days 35 days

How to Use the LCC

Compare the color
of the topmost fully
expanded and
healthy leaf of a
representative rice
plant with the LCC.

2
The LCC comes with six color gradients, starting with yellowish green (1)
representing the lowest N concentration, and dark green (6) or highest N
concentration. The critical value set for irrigated lowland rice variety is 4.

apply 30 kg N/hectare
if majority of the leaves
in a sample have LCC no need to apply fertilizer
readings below 4 if majority of the leaves
(1 1/3 bags urea or in the sample have LCC
3 bags ammonium sulfate) readings above 4

1 2 3 4 5 6

critical value set

for irrigated lowland rice variety

Take readings between 8-10 am when there is not much glare from the
sun. Avoid taking readings very early in the morning since few drops can
make reading difficult.

3
Homogenous Plots
(Fairly level area with uniform crop growth)
Measure the topmost fully expanded healthy leaves of 10 plants from a
plot or hectare if the area is homogenous. If 5 or more of the leaves
have LCC readings below 4, apply 30 kg N/ha. This is equivalent to 1 1/3
bags of urea or 3 bags ammonium sulfate.

PLOT 1
Measure the first fully
expanded leaf of the
tallest tiller.

• leaf 2

• leaf 7
• leaf 6
• leaf 3 • leaf 5

• leaf 1

• leaf 4 • leaf 8

• leaf 9
• leaf 10

1 Hectare

4
Sample Readings from Homogenous Plots
Rule: If 5 or more of the leaves have LCC readings
below 4, apply 30 kg N

LCC Reading

1 2 3 4 5 6

Frequency of
leaves per
LCC reading
II IIII III
Decision: Apply N fertilizer
Since 7 leaves have
LCC readings below 4,
apply 30 kg N/ha

1
30 kg N/ha = 1/3 or 1 1 1

urea ammonium sulfate

5
Heterogenous Plots
(High and low areas with non-uniform crop growth)

If the area is heterogenous, that is, there are low or elevated areas or
different soil nitrogen status, divide the area into several plots of similar
characteristics. Then get LCC readings of 10 representative plants from
each plot. For each plot, if there are five or more leaves with LCC
readings below 4, apply 30 kg N/ha. This is equivalent to 1 1/3 bags
urea or 3 bags ammonium sulfate.

• Leaf 1
• Leaf 3

• Leaf 2 • Leaf 4
• Leaf 6
• Leaf 5

• Leaf 8 • Leaf 9

• Leaf 1 • Leaf 10
• Leaf 3 • Leaf 7
PLOT 1
• Leaf 4
• Leaf 2 • Leaf 6

• Leaf 5
• Leaf 9
• Leaf 8
• Leaf 10
• Leaf 7
PLOT 2

• Leaf 1 • Leaf 3

• Leaf 6
• Leaf 4
• Leaf 8 • Leaf 2

• Leaf 9

• Leaf 10 • Leaf 5
• Leaf 7

PLOT 3

1 Hectare

6
Sample Readings from Heterogenous Plots

Plot 1 LCC Reading

1 2 3 4 5 6

Frequency of
leaves per
IIII- II
LCC reading III
Decision: Apply N fertilizer
Since 8 leaves have
LCC readings below 4,
apply 30 kg N/ha

Plot 2 LCC Reading

1 2 3 4 5 6

Frequency of
leaves per
III IIII-
LCC reading II
Decision: Do not apply N fertilizer
Since only 3 leaves have
LCC readings below 4,
no need to apply N fertilizer

Plot 3 LCC Reading

1 2 3 4 5 6

Frequency of
leaves per
LCC reading
IIII IIII I
Decision: Do not apply N fertilizer
Since all the leaves fall in
LCC 4 and above, no
need to apply N fertilizer

7
Brief History
of the Leaf Color Chart (LCC)
Japan and China were the first to use the leaf color chart (LCC).
Japan used the LCC extensively on crops like corn and rice. Its
practicality and ease of use prompted PhilRice to study its application
in the Philippines. In 1995, PhilRice researchers tested a Japanese
LCC prototype on four Indica rice varieties, PSB Rc2, PSB Rc6, PSB
Rc22, and IR 72. The Japanese LCC measures 10 cm x 35.5 cm with
seven plates or color gradients ranging from yellowish green to dark
green. Researchers found that the LCC readings “matched” the more
accurate readings of leaf nitrogen content by a digital chlorophyll meter
(SPAD) and chemical analysis using Kjedahl method. These two
methods, however, are very expensive and beyond the reach of
ordinary farmers.
With these encouraging results, PhilRice linked up with the Crop
Resource Management Network and International Rice Research
Institute (CREMNET-IRRI) to develop a local prototype, smaller in size
and lighter in weight. The first material used was a laminated photo-
graphic paper measuring 5.5 cm x 13 cm. The LCC still had seven
color gradients. Nueva Ecija farmers had some difficulty comparing the
leaf color to the LCC due to the glare from the glossy surface of the
prototype. Field tests also showed that only six color gradients were
needed or Philippine indica rices. With the assistance of a local
chemical company, a plastic LCC measuring 7 cm x 19.5 cm with six
color plates was developed, as shown in the cover photo. A one-page
instructional handout was initially made to guide farm technicians and
farmers on how to use the LCC. A number of Nueva Ecija farmers
were trained on the use of LCC.
The present LCC was tested in farmers’ fields and over 40 local
varieties including hybrids. Based on positive feedback from farmers
and technicians, the Department of Agriculture procured 15,000 units
of the LCC to be distributed to agricultural technicians nationwide,
including farmer-cooperators in the Gintong Ani technology demonstra-
tion project. Instructions on its use were further simplified for ordinary
farmers to make full use of this inexpensive and practical technology.

8
Acknowledgment
This bulletin was prepared at the Philippine Rice Research Institute (PhilRice)
by Dr. Rolando T. Cruz (subject matter specialist), Dr. Santiago R. Obien
(technical adviser), Roger F. Barroga (technology synthesis); Carlo G. Dacumos
(design and layout), and Arleen Robert E. Baclit (photographs).
For more information, write or call:
Dr. Rolando T. Cruz Dr. Vethaiya Balasubramanian
Division head, ASPPD CREMNET Coordinator, IPMO
PhilRice IRRI, Los Baños, Laguna
 PhilRice
We are a 12-year-old government corporation attached to the Department of
Agriculture. We help our country to locally produce enough rice for all Filipinos. We
develop rice production technologies suited to the different growing conditions in our
country - irrigated, rainfed, upland, cool/elevated, and salty.
We develop and adapt suitable varieties and make these available and accessible
to seed growers and farmers. We collect, document, and preserve seeds of local
traditional rice varieties. We transfer the good qualities of these rices into the modern
rice varieties, making them strong against insect pests and diseases, high-yielding,
delicious to eat, and can thrive in harsh environments.
We develop efficient methods of planting, remedying poor soils, and protecting rice
crops from pests without harming the environment. We develop small farm machines
and approaches to making full use of land and water resources, including postharvest
technologies. To improve rice-based farming systems, we determine the most productive
crops for planting after rice, especially in rainfed areas. We also identify other special
uses of rice and its by-products as food or drink.
Most of all, we promote the adoption of these technologies among rice farmers
and seed producers, agricultural extension and development workers, and rice-based
businessmen. We likewise espouse policies favorable to the rice industry.
We are PhilRice. We serve.
If you feel you're not getting enough of our services, or if there are other services
you desire from us, please let us know. At once.

for more information, PhilRice Maligaya

write, visit, or call: Muñoz, 3119 Nueva Ecija
Tel.: 63 (044) 456-0112, -0113, -0277, -0285, -0258, -0354,
(Mobiline) 63 (0912) 302-9517, 313-5092
Manila Direct: 63 (02) 843-5122 (telefax)
Telefax: 63 (044) 456-0647, -0649
Fax: 63 (044) 456-0112
E-mail: philrice@silang.slu.edu.ph
philrice@mozcom.com
PhilRice Los Baños
UPLB Campus, College, 4031 Laguna
Tel.: 63 (049) 536-3515, 3631 to 33
Fax.: 63 (049) 536-3515
Email: philrice@laguna.net

PhilRice San Mateo

Malasin, San Mateo, 3318 Isabela
Tel. 63 (078) 664-2280
PhilRice Midsayap
Bual Norte, Midsayap
9410 North Cotabato
Tel. 63 (064) 98178
Department of Agriculture
PhilRice Agusan

PhilRice Basilisa, RTRomualdez, 8611 Agusan del Norte

Tel. 0912-715-7857;0918-406-0965/1145