Tài liệu Growths and Carbon Stocks of Para Rubber Plantations on Phonpisai Soil Series in Northeastern Thailand ppt

RUBBER THAI JOURNAL 1:1-18 (2012)
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Growths and Carbon Stocks of Para Rubber
Plantations on Phonpisai Soil Series in
Northeastern Thailand

Chakarn Saengruksawong
Soontorn Khamyong, Niwat Anongrak, Jitti Pinthong

Department of Plant Science and Natural Resources,
Faculty of Agriculture Institution: Chiang Mai University




ARTICLE INFO

Article history:
Revise: 1 January 2012
Revise: in revise
Presentation of IRRDB

Conference, 15-16
December 2011,
Chiangmai, Thailand
Accepted:
12 January 2012
Available online:
15 January 2012


Keywords:
carbon stock, rubber
growth, rubber
plantation, biomass,
Chakkarat soil series


ABSTRACT

Growths and carbon stocks in a series of para rubber
plantations on Chakkarat soil series in northeastern Thailand
were investigated including 1, 5, 10, 15 and 20 years old, and
a natural forest. Totally 15, 40 x 40 m sampling plots were
used for studying rubber growths, three plots per each aged
class plantation and one plot for the natural forest. In each
plot, stem girth at 1.3 m above ground, crown width and
height of trees were measured. One rubber tree having the
mean growth in each aged class plantation was cut and
separated to stem, branch, leaf and root biomass for making
allometry equations. Fifteen soil pits were made in each plot,
and soil samples were collected along soil profile. Soil

physical and chemical properties were analyzed in laboratory.
Rubber tree densities varied between 80-109 trees/rai
(1ha = 6.25 rai). Stem girth and height growths were
increased with the plantation ages. The growths were very
rapid for rubber trees having ages between 1 and 15 years old
and become slow for the older trees. The biomass amounts of
1, 5, 10, 15 and 20 years old plantations were in the order of
21.25, 55.24, 102.39, 140.50 and 215.39 Mg/ha. Ecosystem
carbon stocks in these plantations were increased with tree
ages as 26.29, 48.28, 76.62, 95.83 and 135.38 Mg/ha,
respectively. They involved two compartments; (1) biomass
carbon: 12.03, 31.45, 58.10, 79.78 and 122.01 Mg/ha; and (2)
soil carbon: 14.26, 16.83, 18.52, 16.05 and 13.37 Mg/ha. The
total carbon storage in natural forest was 134.62 Mg/ha;
124.20 Mg/ha in biomass and 10.42 Mg/ha in soil. The young
plantations had the high carbon percentages in soil and low in
biomass whereas carbon allocation in the older plantations
was higher in biomass and lower in soil system.
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Introduction

Thailand is the world leading producer
and exporter of para rubber (herein called
rubber) with production capacity of 3.1 – 3.2
million tons per year, with 88-90 percent of
total production capacity exported to foreign

markets. The country also has high potential
for expanding production area and raising
production capacity. In year 2009, rubber
plantations in Thailand covered 2.70 million ha
across Thailand with the majority (2.10 million
ha) in the traditional areas in the southern (2.61
million ha) and eastern 14.68 million ha)
region and the remaining 0.60 million ha are
planted in new areas in the northeastern (0.45
million ha), northern (0.09 million ha) and
central (0.05 million ha) region.
The northeastern region of Thailand has
agricultural area of 15.90 million ha, of which
6.65 million ha are suitable for rubber
plantation. However, only 3.09 million ha,
have yield more than 1,562 kilogram per ha
per year and currently 0.45 million ha are
being used for rubber plantation. The
remaining 2.65 million ha, an area equal of
total area being for rubber production today, is
still available for additional rubber production.
Hence, northeastern region of Thailand will be
an important rubber production source for
Thailand in the future.
Global warming is a present problem and
spreading throughout the world, encouraging
all nations to take various measures to reduce
global warming under the KYOTO protocol.
The protocol is a part of the United Nations
Framework Convention on Climate Change

(UNFCC), enforced in 2005. Even if Thailand
is a non-annex 1 member country that can
reduce greenhouse gas emission through the
clean development mechanism, the appropriate
approach is to plant para rubber plantation in
place of deforestation in Thailand. Because
rubber trees have production life of 20 years,
the plantation can be considered as forest
plantation as rubber tress increase in biological
mass as they age and has high capacity for
carbon stock storage.
Development of northeastern region as
part of the country’s rubber production
source will need a study on environmental
affect on growth pattern in different areas of
the region, especially rainwater, humidity, soil
characteristic and rock formation. Different
soil qualities have strong affect to the debt of
water drainable, physical, chemical and
biological properties (Bowen & Nambiar,
1989; Fisher & Binkley, 2000). It will also
influence the amount of carbon stock stored in
different age group of rubber trees hence will
affect the environmental role of rubber
plantation and will be an important data for
better management at relevant organizations.
Nongkhai Province has plantation area of
724,590 ha with areas suitable for rubber
plantation of 340,606 ha. It is also the province
with most area used for rubber plantation in its

region, coving 102,051 ha and also has
remaining potential land use of 238,3994 ha.
Moreover, it is the first test province with pilot
plantation project by the Rubber Research
Institute of Thailand (RRIT) in year 1978,
giving it many test plantation aging from 1
year old to 20 years old. Investigation from the
Land Development Department shows that
most soil type found in the area is the
Phonpisai soil coveringin 153,410 ha. Studies
on the growth pattern, bio-productivity, and
carbon stock potential on Phonpisai soil type is
an interesting topic and will provide important
data for the development of management and
encouragement of appropriate rubber
plantation that give high yields and rehabilitate
the environment.

Methods

Research site
The research site is located in Rattanawapi
District and Phonpisai District, Nong Khai
Province. The site is located between latitude
17 degrees 52 minutes north and longitude 102
degrees 44 minutes east. The land elevation
from normal sea level sits between 161-200
meters with incline of 1-7%.

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Growth and biomass of rubber
Three samples are selected from five
different age groups of plantations including 1
year, 5 years, 10 years, 15 years and 20 years
old that are 40 x 40 square meters in size.
Growth studies are done by measurements of
the tree circumference at height of 130
centimeters from the ground as well as
measuring the total height of the tree itself.
Biomass measure for the tree in each age
group are determined by cutting trees with
similar size and height to the average tree in
each plantation, one for each age group.
Samples trees are then divided into trunk,
branch, leaves and roots for analysis between
biomass and D
2
H to determine the carbon in
each part of the tree as well as the entire carbon
stock.

Growth of plant species and biomass in
referenced natural forest
Research samples are selected from
sample sites in natural forest of Phonpisai
District that are in close proximity to pilot

plantation. Natural forests in the area consist of
dipterocarp forest size of 40 x 40 square meters
measuring tree diameter at 130 centimeter
height as well as plant species with height of
over 1.50 meters. The quantitative calculations
of each plant species include the density,
important distinction and indicators.
Qualitative biodiversity data includes listing
names of plant species in the area in both
common and scientific names and calculation
the biomass of plant species with the following
formula Ogino et al. (1967)

W
S
(trunk) = 189 (D
2
H)
0.902

W
B
(branhc) = 0.125 W
S
1.024

1/W
L
(leaves) = (1/W
S

0.9
) + 0.172

when W = biomass (kilograms per hectare)
D = diameter at 1.3 meters from ground
(meters)
H = tree height (meters)

Soil characteristics, carbon stocks and
nutrition
Soil studies affecting rubber and plant
species growth in sample plantations and
natural forests are conducted by digging for
three sample soils in plantations aged 1, 5, 10,
15 and 20 years old as well as one sample soil
in natural forests, totaling 16 dig sites. Each
dig sites are 1.5 meters wide, 2.0 meters long
and 1.2 meters deep. Studies and analysis on
soil characteristic are done by studying the
physical and chemical properties of the soil.
Physical properties studied includes (1) total
soil density of the soil through the core
method, (2) gravel quantity for size more than
2 mm by weighting method, and (3) particle-
size distribution and soil texture by
hydrometer method. Chemical property
studied includes (1) soil reaction by pH meter
method in ratio of 1:1 with water, (2) carbon
exchange capcity (CEC), (3) total nitrogen by
micro Kjedahl method, (4) organic matter and

carbon in soil by wet oxidation method of
Walkley and Black (Nelson and Sommers,
1982), (5) useful phosphorous concentration
by Bray II and colorimetric method, (6) useful
potassium level by extracting with ammonium
acetate 1N, pH 7.0 and measured by flame
photometer and (7) calcium and magnesium
concentration extracted with ammonium
acitate 1 N, pH 7.0 and measured by atomic
absorption tool. Calculations of carbon level in
soil from soil mass and carbon concentration
fluctuation in each soil level were also
conducted.

Results and Discussion

Growths
Growth of rubber consists of the diameter,
height and bush size which will differentiate
between age groups.
Table 1 shows the growth of rubber tree in
each age group. It is found that the density of
the rubber tree varies a little. The density of
age groups 1, 5, 10, 15 and 20 years old
averages at 78, 71, 79, 81 and 85 respectively.
The circumference of the tree increases as the
tree age. Trees aged 1, 5, 10, 15 and 20 years
old have average circumference of 8.23, 29.42,
36.76, 53.54 and 54.45 respectively. The
average heights are 6.49, 8.83, 11.98, 15.41

and 14.46 centimeter and bush sizes of 2.60,
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4.80, 5.30, 6.40 and 5.70 centimeters
respectively.
As for the amount of rubber tree that can
be harvested according to recommendations of
the RRIT, it is found that 5 years old
plantations do not have trees with
circumference higher than 50 centimeters, the
size appropriate for harvesting. Only 1.69% of
10 years old trees have circumference
measurement higher than 50 centimeters. The
ratio increases to 65.88% and 67.45% for 15
and 20 years old plantations respectively.
For the diameter of the trees, the standard
used for rubber wood purchases, it is found
that pilot plantations have diameters of 6
inches or more for 10 years old plantations.
However, only 5.91% of 10 years old tress
have diameter more than 6 inches and
increases to 53.31% and 56.86% for 15 and 20
years old plantations respectively.
Compared to southern rubber plantations,
the circumference, diameter and ratio of
harvest-read samples of the rubber trees in the
northeastern region is lower. This is due to the

lower fertility of the soil in the northeastern
region.
As for the height and branching level
comparison with the southern region, pilot
plantations in the northeastern region are
similar to that of the southern region for the
same age groups.

Biomass
Average biomass for the pilot plantation
in each age group from 1, 5, 10, 15 and 20
years old equals to 3.2, 43.0, 94.5, 278.8 and
264.9 kilograms per tree respectively. Table 2
shows the biomass per area with plantations
aging 1, 5, 10, 15 and 20 years old having total
biomass of 1.54, 19.10, 46.66, 140.56 and
140.73 Mg/ha respectively.
1 year old plantation has average
biomass of 1.54 Mg/ha Biomass from trunk,
branch, leaves and roots equal 0.63, 0.13, 0.25
and 0.52 Mg/ha respectively, calculated into a
ratio of 37.07, 30.13, 6.69 and 26.15 percent
respectively. 5 years old plantation has
average biomass of 19.10 Mg/ha Biomass
from trunk, branch, leaves and roots equal
7.07, 5.75, 1.28 and 5.00 Mg/ha respectively,
calculated into a ratio of 40.84, 8.73, 16.41 and
34.02 percent respectively. 10 years old
plantation has average biomass of 46.66
Mg/ha Biomass from trunk, branch, leaves and

roots equal 15.43, 18.59, 2.23 and 10.41 Mg/ha
respectively, calculated into a ratio of 33.07,
39.84, 4.67 and 22.30 percent respectively. 15
years old plantation has average biomass of
140.56 Mg/ha Biomass from trunk, branch,
leaves and roots equal 39.01, 72.50, 4.31 and
2.49 Mg/ha respectively, calculated into a ratio
of 27.29, 52.37, 2.97 and 17.36 percent
respectively. 20 years old plantation has
average biomass of 140.73 Mg/ha Biomass
from trunk, branch, leaves and roots equal
39.01, 72.50, 4.31 และ 2.49 Mg/ha respectively,
calculated into a ratio of 27.72, 51.52, 3.06 and
17.70 percent respectively.
Biomass of rubber trees increases as they
age with very fast rate from 1 to 15 years old
and slows down during 15 to 20 years old. The
ratio of biomass accumulation in each part of
the tree also changes as they age. In plantation
aged 1, 5, 10, 15 and 20 years old, the ratio of
biomass accumulation compared to the total
biomass equals to 40.84, 37.03, 33.07, 27.29
and 27.72 respectively. The ratio for the
branch increases as the tree age, from 8.73 to
30.13, 39.84, 52.37 and 52.52 percent
respectively. In contrast, the ratio for the leaves
and roots decreases.

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Fig. 1. Stem girth and height growths, and biomass of para rubber in 1-, 5-, 10-, 15- and 20-year-old
plantations on Phonpisai soil series


Ponpisai
0
10
20
30
40
50
60
70

80
90
100
1 5 10 15 20
Plantation ages (years)
GBH (cm)
Rep.1
Rep.2
Rep.3

Ponpisai
0
5
10
15
20
25
30
1 5 10 15 20
Plantation ages (years)
H (m)
Rep.1
Rep.2
Rep.3

Ponpisai
0
5,000
10,000
15,000

20,000
25,000
30,000
35,000
40,000
1 5 10 15 20
Plantation ages (years)
Biomass (kg/rai)
Rep.1
Rep.2
Rep.3




Table 1. Growths and biomass of para rubber in different age plantations on Phonpisai soil series

Plantation
Plot
Density
GBH
Height
Crown
width
Biomass
age (years)
No.
(trees/rai)
(cm)
(m)

(m)
(kg/tree)
1
1
79
8.86 + 1.97
6.57 + 0.83
2.70 + 0.20
3.6

2
78
7.69 + 1.56
6.53 + 0.69
2.60 + 0.20
2.8

3
77
8.13 + 2.22
6.36 + 0.70
2.60 + 0.20
3.1

Mean
78
8.23 + 1.99
6.49 + 0.75
2.60 + 0.20
3.2

5
1
71
31.92 + 4.86
8.86 + 0.30
5.10 + 0.80
50.0

2
71
30.86 + 5.33
8.84 + 0.39
5.20 + 0.80
46.8

3
71
25.50 + 5.39
8.78 + 0.41
4.10 + 0.80
33.3

Mean
213
29.42+ 5.89
8.83 + 0.37
4.80 + 0.90
43.0
10
1

80
34.79 + 9.12
12.04 + 1.45
4.80 + 0.60
87.6

2
79
34.60 + 6.66
12.03 + 1.26
5.20 + 0.80
81.7

3
78
40.96 + 7.23
11.87 + 1.17
5.90 + 0.60
114.5

Mean
237
36.76 + 8.26
11.98 + 1.30
5.30 + 0.80
94.5
15
1
86
50.92 + 10.63

15.34 + 0.93
6.60 + 1.60
246.7

2
77
52.23 + 11.77
15.34 + 0.66
7.20 + 1.50
263.4

3
79
57.67 + 11.25
15.55 + 0.61
6.40 + 1.60
328.7

Mean
242
53.54 + 11.54
15.41 + 0.76
5.70 + 1.60
278.8
20
1
85
54.90 + 11.20
15.07 + 1.58
5.70 + 1.40

284.1

2
86
53.05 + 8.89
14.22 + 1.18
5.70 + 1.40
244.1

3
84
55.44 + 10.65
14.08 + 1.14
5.70 + 1.40
266.8

Mean
255
54.45 + 10.30
14.46 + 1.38
5.70 + 1.40
264.9

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Table 2. Biomass of para rubber in different age plantations on Phonpisai soil series

Plantation
Plot
Density
Biomass (kg/rai)
Total Biomass
age (years)
No.
Tree/rai
Ws
Wb
Wl
Wr
Total
(Mg/ha)
1
1
79
116.7
26.4
45.1
96.4
284.5
1.78

2
78
88.7
17.3
37.4
74.7

218.1
1.36

3
77
97.0
20.9
39.0
80.8
237.8
1.49
Mean 78 100.8 21.5 40.5 83.9 246.8 1.54

%

40.84
8.73
16.41
34.02
100

5
1
71
1,297.9
1,115.6
225.5
909.8
3,548.8
22.18

2 71 1,222.9 1,025.1 216.1 860.2 3,324.3 20.78

3
71
874.1
621.9
171.3
627.9
2,295.3
14.35

Mean
71
1,131.6
920.9
204.3
799.3
3,056.1
19.10

%

37.03
30.13
6.69
26.15
100

10 1 80 2,303.1 2,810.0 339.9 1,557.9 7,010.9 43.82

2
79
2,203.8
2,417.4
332.5
1,500.2
6,453.9
40.34

3
78
2,898.9
3,695.4
399.3
1,936.8
8,930.5
55.82

Mean
79
2,468.6
2,974.3
357.3
1,665.0
7,465.1
46.66


%
33.07

39.84
4.79
22.30
100

15
1
86
5,947.2
10,789.2
668.6
3,808.8
21,213.8
132.59

2
77
5,592.4
10,505.6
617.7
3,568.0
20,283.7
126.77
3 79 6,875.0 14,037.3 719.3 4,338.7 25,970.3 162.31

Mean
81
6,138.2
11,777.4
668.56

3,905.1
22,489.3
140.56

%

27.29
52.37
2.97
17.36
100

20
1
85
6,584.9
12,665.6
714.3
4,186.4
24,151.2
150.95

2
86
5,933.2
10,584.5
670.4
3,805.0
20,993.1
131.21

3
84
6,208.3
11,551.8
685.4
3,961.9
22,407.4
140.05
Mean 85 6,242.2 11,600.6 690.0 3,984.4 22,517.3 140.73

%

27.72
51.52
3.06
17.70
100


Changes in Soil Characteristics with
Plantation Ages
Physical and chemical properties of the
soil are shown in Table 3 and Table 4.

1. Physical properties
Soil texture: the soil in nearby
dipterocarp forest is considered the natural
soil in the area. The top soil is sandy clay
loam soil and bottom soil is clay. Soil

texture in top soil found natural forest and
1, 5, 15 and 20 years old rubber plantations
to have sandy clay loam and 10 years old
planation to have clay soil. For bottom soil,
natural forest and 20 years old plantations
have clay soil, 1 and 10 years old
plantations have sandy clay loam to clay
and 5 and 15 years old plantation have
sandy clay loam to clay soil.

Bulk density: The top soil of
natural forest has medium density (1.52
Mg.m
-3
) and bottom soil has low to high
density. Soil of 1, 5 and 10 years old
plantation has very high density (2.21
Mg.m
-3
) and 15 years old plantation has
medium density (1.52 Mg.m
-3
). However,
20 years old plantation has fairly low
density (1.33 Mg.m
-3
). Bottom soil has high
fluctuation with values from fairly low to
very high and no difference is found
between age groups.

Particle density: Top soil in natural
forest has value of 2.09 Mg.m
-3
and increase
slightly according to the depth. Soil for
plantations aged 1, 5, 10, 15 and 20 years
old has values of 2.42, 2.66, 2.55, 2.28 and
2.39 Mg.m
-3
respectively. The values are
fairly higher than natural forest but no
changes are observed between natural forest
age groups. Bottom soil have fluctuated
values similar to the top soil and no changes
between plantation age groups.
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Rubber trees in plantations affect the
property of the soil such as the temperature
and humidity, which in turns affects the
decomposition of rocks and minerals as
well as the decrease of top soil erosion as
the trees age. For the soil and density of the
soil itself, it is found that there is little
changes and no differences are observed
between each age groups.

2. Soil chemical properties
pH: Top soil and bottom soil of
plantations aged 1, 5, 10, 15 and 20 years old
have high reaction level of 4.6-5.0 pH. The
levels are similar to the nearby forest and no
difference between age groups is observed.

Organic matter contents: Top soil in the
Ap region for the plantation agede 1, 5, 10, 15
and 20 years old have values of 46.6, 12.1,
17.6, 28.6 and 15.1 g/kg respectively. The
values are medium to high and there is no
difference between age groups, which could
result from irregular use of fertilizers. The
bottom soil have fairly low to very low values
while natural forest have fairly high value of
32.9 g/kg in top soil and low to very low in
bottom soil.
The amount of organic carbon and
nitrogen are subject to change similar to the
other organic matter in the soil.

Available phosphorous: Top soil in
plantation aged 1, 5, 10, 15 and 20 years old
have values of 3-5 mg.kg
-1
which is low.
Bottom soil has very low level. For natural
forest, top level have fairly low level (7

mg.kg
-1
) and low to very low for bottom soil.

Available potassium: Top soil in
plantation aged 1, 5, and 10 years old have low
to medium values (47-83 mg/kg) and high
level in 15 and 20 years old plantations (100-
110 mg/kg). Bottom soil has high fluctuation
from low to very high but no difference
between age groups. Natural soil has high
levels across the soil levels.

Cation exchange capcity: Top soil in
plantations aged 1, 5, 10, 15 and 20 years old
have values of 7.6, 4.1, 7.1, 6.4 and 3.6
cmol/kg respectively. The levels are fairly low
to low and no difference is observed between
age groups. Bottom soil has high fluctuation
from low to fairly high but no difference
between age groups. For top soil in natural
forest, the level is fairly low and for the bottom
soil it is medium to fairly high level.

Base saturation: Top soil in plantations
aged 1, 5, 10, 15 and 20 years old have values
of 51.40, 26.79, 24.12, 35.10 and 24.75%
respectively. The levels are low to medium and
no difference between age groups. Natural
forest has medium level in top soil and low

level in bottom soil.
Decomposed leaves and parts above the
soil of the rubber tree on the ground, as well as
the dead roots, will decompose to organic
matter in the soil and release various nutrient
into the ground. The quantity should increase
as the trees growth. However, there are no
different in the chemical property of the soil
between the age groups. This may due to the
organic matter and nutrient being used and
stored in the biomass. Some parts are lost with
the top soil erosion. Moreover, the use of
fertilizers can also cause high fluctuation in the
organic matter of the top soil.

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Table 3. Soil physical properties under different age rubber plantations and adjacent dry dipterocarp forest on
Ponpisai soil series

Horizon Depth (cm)
Particle size distribution (%)
Gravel Bulk density Particle density


sand silt clay (%) Mg m
3

1-year-old

Ap 0-18 63.52 16.00 20.48 56.70 2.21 2.42
Btcv1 18-40 49.52 6.00 44.48 44.10 2.22 2.49
Btcv2 40-82/88 51.52 8.00 40.48 59.86 2.25 2.58
Btv 82/88-135/158 23.52 18.00 58.48 1.41 2.04 2.23
BCv1 135/158-190 13.52 26.00 60.48 2.87 2.07 2.23
BCv2 190-210+ 9.52 32.00 58.48 1.61 2.01 2.14
5-year-old

Ap 0-19 65.52 12.00 22.48 35.38 2.21 2.66
Btcv1 19-36 61.52 8.00 30.48 26.66 2.24 2.65
Btcv2 36-110 41.52 10.00 48.48 29.25 1.80 2.59

Btcv3 110-143 39.52 14.00 46.48 36.20 2.25 2.45
BCv1 143-182 41.52 12.00 46.48 32.83 2.33 2.50
BCv2 182-210+ 31.52 18.00 50.48 35.63 2.32 2.54
10-year-old

Ap 0-19 43.52 12.00 44.48 50.56 2.20 2.55
Btcv1 19-46 25.52 10.00 64.48 20.40 2.24 2.51
Btcv2 46-92/101 33.52 16.00 50.48 51.01 1.53 2.51
Btcv3 92/101-135 51.52 10.00 38.48 5.16 1.40 2.51
BCv1 135-182 53.52 10.00 36.48 6.07 1.97 2.49
BCv2 182-210+ 35.52 16.00 48.48 9.65 1.90 2.52
15-year-old

Ap 0-20 48.80 24.00 27.20 42.91 1.58 2.28
Btcv1 20-40 30.80 18.00 51.20 37.28 1.59 2.45
Btcv2 40-80 22.80 20.00 57.20 19.71 1.35 2.49
Btv1 80100 22.80 22.00 55.20 1.59 1.33 2.28
Btv2 100-140 14.80 16.00 69.20 1.09 1.44 2.23
BCv1 140-180 28.80 20.00 51.20 8.76 1.50 2.15
BCv2 180-210+ 12.80 28.00 59.20 7.35 1.49 2.40
20-year-old

Ap 0-17 66.80 12.00 21.20 14.49 1.33 2.39
Btcv1 17-40 50.80 18.00 31.20 79.74 1.59 2.69
Btcv2 40-107 38.80 12.00 49.20 25.73 1.69 2.32
BCv1 107-145 34.80 18.00 47.20 31.19 1.61 2.42
BCv2 145-185 30.80 26.00 43.20 22.37 1.69 2.25
BCv3 185-203+ 34.80 24.00 41.20 11.28 1.61 2.40

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9

Table 3. Soil physical properties under different age rubber plantations and adjacent dry dipterocarp forest
on Ponpisai soil series

Horizon Depth (cm)
Particle size distribution (%)
Gravel Bulk density Particle density


sand silt clay (%) Mg m
3

Dry dipterocarp forest

A 0-5 57.52 16.00 26.48 54.08 1.52 2.09
BA 5-15 35.52 18.00 46.48 34.04 1.96 2.17
Btcv1 15-50 13.52 32.00 54.48 36.72 1.79 2.07
Btcv2 50-98 5.52 40.00 54.48 18.77 1.24 2.09

Btv 98-154 13.52 32.00 54.48 14.59 1.19 2.21
BCv 154-210+ 29.52 16.00 54.48 43.49 1.25 2.29

Table 4. Soil chemical properties under different age rubber plantations and adjacent dry dipterocarp forest on
Ponpisai soil series

Horizo

Depth
pH
OM
C
N
Avail.

Avail.

CEC
EA
BS

(cm)


g/kg

mg/kg
cmol /kg

%

1-year-old





Ap 0-18 4.9 46.6 27.02 1.93 5 83 7.6 1.92 51.40
Btcv1
18-40
5.0
11.2
6.49
0.78
1
82
7.7
4.14
22.12
Btcv2
40-82/88
4.6
5.8
3.36
0.25
2
77
8.2
4.53
21.96
Btv

82/88-135/158
4.7
2.5
1.45
0.13
1
100
14.4
12.12
6.82
BCv1
135/158-190
4.7
1.8
1.04
0.10
1
110
15.1
13.55
5.25
BCv2
190-210+
4.5
2.0
1.16
0.10
1
193
15.6

13.60
8.11
5-year-old








Ap
0-19
4.7
12.1
7.01
0.72
3
47
4.1
2.07
26.79
Btcv1 19-36 4.6 10.6 6.14 0.73 2 69 5.1 3.15 22.37
Btcv2 36-110 4.8 5.4 3.13 0.35 1 62 6.3 3.65 19.51
Btcv3 110-143 4.9 1.7 0.98 0.10 1 63 3.3 2.27 25.54
BCv1
143-182
4.9
2.7
1.56

0.10
2
83
7.4
5.76
13.72
BCv2
182-210+
4.8
2.5
1.45
0.10
1
80
7.0
5.76
13.04
10-year-old








Ap
0-19
5.0
17.6

10.20
1.29
3
86
7.1
3.55
24.12
Btcv1
19-46
4.9
10.7
6.20
0.74
1
88
7.8
4.19
17.81
Btcv2
46-92/101
5.0
5.7
3.30
0.29
1
88
6.9
3.35
19.99
Btcv3

92/101-135
5.0
5.0
2.90
0.10
1
61
6.1
3.01
22.78
BCv1 135-182 4.9 5.0 2.90 0.10 1 77 8.3 5.67 13.32
BCv2 182-210+ 4.7 3.9 2.26 0.10 1 80 9.6 6.50 9.23
15-year-old









Ap
0-20
4.8
28.5
16.53
1.10
4
100

6.4
2.41
35.10
Btc1
20-40
4.8
13.6
7.88
0.71
1
87
8.6
5.62
14.36
Btc2
40-80
4.8
6.2
3.59
0.37
1
103
8.8
5.12
19.69
Btv3
80-100
4.7
3.0
1.74

0.27
1
85
10.9
8.77
7.26
2Btv4
100-140
4.7
3.0
1.74
0.10
1
109
14.0
11.68
5.37
2BCv1
140-180
4.6
1.3
0.75
0.10
1
121
11.4
9.90
5.29
2BCv2
180-210+

4.7
1.7
0.98
0.10
1
105
11.6
10.69
4.62
20-year-old








Ap 0-17 4.8 15.1 8.75 0.88 3 110 3.6 2.07 24.75
Btcv1 17-40 4.8 12.6 7.30 0.58 2 57 5.2 3.30 10.56
Btcv2
40-107
4.9
5.4
3.13
0.38
1
44
7.3
5.08

13.48
BCv1
107-145
4.9
2.7
1.56
0.10
1
44
7.3
5.86
7.14
BCv2
145-185
4.9
2.0
1.16
0.10
1
36
6.9
5.42
6.50
BCv3
185-203+
4.6
1.7
0.98
0.10
1

36
6.3
5.76
6.00
Dry dipterocarp forest

A
0-5
5.0
32.9
10.08
1.80
7
110
7.7
1.63
70.10
BA
5-18
4.7
17.9
10.38
1.06
5
97
12.6
8.03
26.27
Btcv1 18-50 4.7 10.2 5.91 0.64 4 113 16.9 13.25 17.79
Btcv2 50-98 4.7 6.0 3.48 0.26 3 113 17.2 14.18 14.84

Btv 98-154 4.8 3.0 1.74 0.18 2 120 18.4 15.47 13.30
BCv
154-210+
4.6
3.7
2.14
0.17
8
128
19.0
15.47
15.48
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10

Carbon Stocks in Para Rubber Plantations
and Natural Forest
1. Biomass carbon storages
(1) Rubber plantations
Rubber trees synthesis light and absorb
carbon dioxide to produce carbohydrate. This
result in carbon accumulation in organic form.
The estimate of carbon accumulation level can
be calculated from the biomass (dry mass).
Hence, biomass is related to the growth rate
and density of the rubber tree in each age group.
Biomass data and analysis of carbon level
in each part of the tree can be used to calculate

carbon stock in the biomass. The density of
carbon in the trunk varies very little between 1
to 20 years old tree between 56.0 to 57.50%.
For the leaves and roots, the average is at 54.89
and 57.08% respectively. As shown in Table 5,
it can be seen that plantations aged 1, 5, 10, 15
and 20 years old have carbon level in the
biomass in total of 0.87, 10.92, 26.68, 80.23
and 80.57 Mg/ha respectively.
1 year old plantation has average carbon
in biomass of 0.87 Mg/ha, divided into trunk,
branch, leaves and roots equal to 0.36, 0.08,
0.14 and 0.30 Mg/ha respectively. 5 years old
plantation has average carbon in biomass of
10.92 Mg/ha, divided into trunk, branch,
leaves and roots equal to 4.06, 3.31, 0.70 and
2.85 Mg/ha respectively. 10 years old
plantation has average carbon in biomass of
26.68 Mg/ha, divided into trunk, branch,
leaves and roots equal to 8.84, 10.67, 1.23 and
5.94 Mg/ha respectively. 15 years old
plantation has average carbon in biomass of
80.23 Mg/ha, divided into trunk, branch,
leaves and roots equal to 2.19, 42.06, 2.29 and
13.93 Mg/ha respectively. 20 years old
plantation has average carbon in biomass of
80.57 Mg/ha, divided into trunk, branch,
leaves and roots equal to 22.36, 41.62, 2.37
and 14.21 Mg/ha respectively.
Carbon stock in biomass for rubber

plantation increase as they age, with highest
rate during 1 to 15 years old trees and slow
down in 15 to 20 years old trees. The ratio of
biomass in each organ changes as the trees age
similar to the biomass level. Compared to
RRIM 600 in 25 years old plantation of eastern
region, it is found that the sample 20 years old
plantations have less carbon stock than in
rubber plantation of eastern region. This is due
to the lower growth period from dry climate,
low soil fertility and high density of trees in
each plantation of up to 91 trees/rai.
(2) Natural forest
Table 6 and 7 shows that dipterocarp
forest has 76 plant species with density as high
as 1,119 trees/rai. Specie with highest density
is the S. obtusa with S. siamensis and C.
subulatum. Specie with highest significant
factor is the S. obtusa (18.05% of all species)
and S. siamensis, C. subulatum, C. formosum
and M. edule having 15.86%, 10.23%, 3.61%
and 2.77% significant factor respectively. The
five species have aggregate significant factor
of 50.52% of all plant species. Biomass of all
plant species equals 92.48 Mg/ha, divided into
trunk, branch, leaves and roots to 60.21, 15.54,
2.84 and 13.89 Mg/ha respectively. Carbon
sock level in biomass equals to 45.68 Mg/ha,
divided into trunk, branch, leaves and roots to
30.04, 7.57, 1.37 and 6.70 Mg/ha respectively.

Species with highest accumulation are the S.
siamensis, S. obtuse, C. subulatum, T. alta, D.
obtusifolius, respectively.
Originally, dipterocarp forest was in bad
condition with maintenance level similar to 20
years old plantations. It is a forest recovering
fertility with biomass around 92.48 Mg/ha
Most biomass, 53.20%, comes from three
species in S. obtuse, S. siamensis and C.
subulatum. The rest of 46.80% are biomass of
the other 73 plant species with values similar
to 7-15 years old rubber plantations.
The creation of rubber plantation is thus an
increase in carbon stock for the environment
that is facing global warming. When compared
to the rubber plantation covering 0.45 million
ha, the northeastern region can contain 18-23
million metric tons for the earth atmosphere.
However, the observed plantations were
not maintained properly. If farmers can develop
proper planting technique and maintenance
procedure, the plantations in the northeastern
region will be an important area for rubber and
carbon production, similar to the level of the
southern region.
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11

Ponpisai
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
1 5 10 15 20
Plantation ages (years)
C (kg/rai)
Rep.1
Rep.2
Rep.3

Fig. 2 Biomass carbon stocks in rubber plantations on Phonpisai soil series


Table 5. Biomass carbon storages in rubber plantations on Ponpisai soil series

Plantation Plot Carbon amounts (kg/rai)
Total biomass
carbon
Age (years)
No.
Stem
Branch

Leaf
Root
Total
(Mg/ha)
1
1
66.3
15.1
24.7
55.0
161.1
1.01

2
50.4
9.9
20.5
42.6
123.4
0.77

3
55.2
11.9
21.4
46.1
134.6
0.84

Mean

57.3
12.3
22.2
47.9
139.7
0.87
5
1
745.8
641.1
123.8
519.3
2,030.0
12.69

2
702.7
589.1
118.6
491.0
1,901.4
11.88
3 502.3 357.4 94.0 358.4 1,312.1 8.20
Mean 650.2 529.2 112.1 456.2 1,747.8 10.92
10
1
1,320.1
1,613.1
186.6
889.2

4,009.0
25.06

2
1,263.2
1,387.7
182.5
856.3
3,689.7
23.06

3
1,661.6
2,121.4
219.2
1,105.5
5,107.7
31.92

Mean
1,415.0
1,707.4
196.1
950.3
4,268.8
26.68
15 1 3,400.7 6,165.4 367.0 2,174.0 12,107.1 75.67

2
3,197.8

6,003.4
339.1
2,036.5
11,576.8
72.36

3
3,931.2
8,021.5
394.9
2,476.4
14,824.0
92.65

Mean
3,509.9
6,730.1
367.0
2,229.0
12,836.0
80.23
20
1
3,774.7
7,271.3
392.1
2,389.5
13,827.6
86.22
2 3,401.1 6,076.5 368.0 2,171.8 12,017.5 75.11

3 3,558.8 6,631.9 376.2 2,261.4 12,828.3 80.18

Mean
3,578.2
6,659.9
378.8
2,274.2
12,891.1
80.57

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12


Table 6. Plant biomass in the natural dry dipterocarp forest

Species Plant name Biomass (kg/rai)
No.

Stem
Branch
Leaf
Root
Total
1
Shorea siamensis
2,017.58
477.95

103.48
476.76
3,075.77
2
Shorea obtusa
1,828.23
425.48
96.17
440.62
2,790.49
3
Canarium subulatum
1,309.90
354.00
55.39
286.79
2,006.09
4
Terminalia alata
811.76
342.82
13.59
134.26
1,302.44
5
Dipterocarpus obtusifolius
716.11
190.89
30.63
156.03

1,093.66
6
Syzygium cumini
466.03
117.73
22.04
107.84
713.63
7
Careya sphaerica
233.48
67.63
8.50
47.85
357.46
8
Ulmus lancaefolia
204.37
54.84
8.59
43.95
311.75
9
Irvingia malayana
181.66
39.90
10.29
46.32
278.18
10

Bombax anceps
173.79
62.21
3.55
30.45
270.00
11
Quercus kerrii
166.93
41.22
8.08
38.40
254.62
12
Walsura robusta
144.48
36.02
6.89
33.13
220.51
13
Stereospermum fimbriatum
129.51
32.44
6.13
29.54
197.63
14
Dalbergia velutina
121.78

23.28
7.91
33.20
186.16
15
Spondias pinnata
77.28
20.51
3.34
17.15
118.28
16
Cratoxylum pruniflorum
73.94
11.42
5.71
24.09
115.17
17
Flemingia macrophylla
72.88
18.40
3.44
17.25
111.98
18
Zizyphus oenoplia
70.28
17.87
3.26

16.06
107.47
19
Strychnos nux-vomica
65.63
15.91
3.25
15.13
99.91
20
Buchanania latifolia
63.18
11.77
4.21
17.89
97.05
21
Pterocarpus macrocarpus
55.23
14.67
2.36
12.01
84.28
22
Sindora siamensis
46.49
7.96
3.32
14.04
71.82

23
Litsea glutinosa
46.79
10.07
2.71
12.01
71.59
24
Memecylon sp.
42.82
5.85
3.56
14.94
67.16
25
Aporosa villosa
39.98
6.42
2.98
12.33
61.72
26
Zizyphus mauritiana
38.73
8.55
2.17
9.60
59.05
27
Macaranga denticulata

37.90
6.41
2.73
11.43
58.47
28
Schoepfia fragrans
33.01
5.80
2.30
9.56
50.67
29
Symplocos recemosa
29.53
5.81
1.87
7.98
45.19
30
Olea salicifolia
27.55
4.74
1.95
8.08
42.32
31
Mimusops elengi
23.90
3.50

1.89
7.85
37.13
32
Mitragyna rotundifolia
20.19
3.10
1.55
6.43
31.27
33
Ampelocissus martinii
20.25
3.24
1.51
6.22
31.21
34
Garuga pinnata
19.01
4.25
1.05
4.65
28.95
35
Tristaniopsis burmanica
18.69
4.20
1.03
4.54

28.46
36
Wendlandia tinctoria
16.99
3.35
1.07
4.51
25.91
37
Garcinia sootepensis
16.14
3.04
1.06
4.44
24.69
38
Phyllanthus emblica
14.57
2.12
1.16
4.83
22.68
40
Memecylon scutellatum
11.85
1.56
1.00
4.23
18.65
41

Macalanga denticulata
9.46
1.72
0.64
2.67
14.49
42
Antidesma acidum
8.59
0.94
0.80
3.43
13.77
43
Vitex pinnata
8.34
1.09
0.71
3.02
13.17
44
Croton roxburghii
8.29
1.48
0.57
2.37
12.72
45
Dalbergia oliverli
7.45

0.96
0.64
2.67
11.72
46
Mitrephora vandaeflora
6.70
0.85
0.58
2.44
10.57
47
Climber
6.83
1.03
0.53
2.17
10.56
48
Catunaregam spathulifolia
6.56
0.80
0.58
2.45
10.38
49
Vitex peduncularis
6.45
0.95
0.52

2.18
10.09
50
Terminalia chebula
6.28
1.14
0.43
1.76
9.61
51
Artocarpus lakoocha
6.09
0.81
0.51
2.12
9.53
52
Hymenodictyon orixense
5.10
0.89
0.36
1.47
7.81
53
Garcinia cowa
4.97
0.71
0.40
1.65
7.74

54
Lithocarpus elegans
4.85
0.66
0.40
1.68
7.59
55
Bridelia affinis
4.06
0.45
0.38
1.61
6.49
56
Antidesma ghaesembilla
4.07
0.67
0.30
1.23
6.27
57
Antidesma velutinosum
3.76
0.53
0.30
1.26
5.86
58
Colona floribunda

2.95
0.46
0.22
0.92
4.55
59
Pavetta sp.
2.14
0.26
0.19
0.79
3.38
60
Arytera littoralis
2.11
0.31
0.17
0.69
3.27
61
Ochna intergerima
1.94
0.20
0.19
0.80
3.12
62
Ilex umbellata
1.91
0.27

0.15
0.63
2.96
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13

Species
Plant name
Biomass (kg/rai)
No.

Stem
Branch
Leaf
Root
Total
63
Artabotrys vanprukii
1.91
0.27
0.15
0.63
2.96
64
Rhus javanica
1.41
0.17
0.13

0.53
2.24
65
Pavetta tomentosa
1.36
0.14
0.13
0.56
2.20
66
Flacourtia indica
1.33
0.18
0.11
0.46
2.08
67
Aganosma marginata
1.27
0.17
0.11
0.44
1.98
68
Dalbergia cultrata
1.06
0.11
0.10
0.44
1.70

69
Euodia roxburghiana
0.84
0.10
0.07
0.31
1.33
70
Brucea javanica
0.68
0.06
0.07
0.30
1.10
71
Anneslea fragrans
0.53
0.06
0.05
0.21
0.85
72
Gnetum montanum
0.46
0.05
0.04
0.19
0.74
73
Lepisanthes rubiginosa

0.39
0.03
0.04
0.18
0.64
74
Bridelia affinis
0.38
0.04
0.04
0.16
0.61
75
Mitragyna hirsuta
0.25
0.02
0.02
0.11
0.40
76
Antidesma sp.
0.13
0.01
0.01
0.06
0.22

Total (kg/rai)
9,633.24
2,487.11

453.64
2,222.51
14,796.51

Total (Mg/ha)
60.21
15.54
2.84
13.89
92.48


Table 7. Biomass carbon storages in the natural dry dipterocarp forest

Speci


Biomass Carbon
No.
Plant name
Stem
Branch
Leaf
Root
Total




kg/rai

1
Shorea siamensis
1,006.77
232.7625
49.98116
229.797
1,519.32
2
Shorea obtuse
912.29
207.2073
46.44858
212.3778
1,378.32
3
Canarium

653.64
172.3998
26.7556
138.2349
991.03
4
Terminalia alata
405.07
166.9533
6.565862
64.71458

643.30
5
Dipterocarpus

357.34
92.9636
14.79587
75.20499
540.30
6
Syzygium cumini
232.55
57.33505
10.64413
51.97803
352.51
7
Careya sphaerica
116.51
32.9359
4.103232
23.06325
176.61
8
Ulmus lancaefolia
101.98
26.70888
4.149266
21.18202
154.02

9
Irvingia malayana
90.65
19.43306
4.969958
22.32803
137.38
10
Bombax anceps
86.72
30.29821
1.713537
14.67929
133.41
11
Quercus kerrii
83.30
20.07172
3.900394
18.50887
125.78
12
Walsura robusta
72.10
17.5394
3.327114
15.96767
108.93
13
Stereospermum

64.63
15.79787
2.961339
14.24007
97.63
14
Dalbergia velutina
60.77
11.33827
3.819067
16.0013
91.92
15
Spondias pinnata
38.56
9.987194
1.613094
8.265305
58.43
16
Cratoxylum

36.90
5.562423
2.758679
11.61181
56.83
17
Flemingia

36.37
8.962849
1.662597
8.31536
55.31
18
Zizyphus oenoplia
35.07
8.704733
1.572595
7.738956
53.09
19
Strychnos nux-

32.75
7.746399
1.57074
7.290428
49.36
20
Buchanania

31.53
5.729612
2.035808
8.623143
47.92
21

Pterocarpus

27.56
7.14656
1.141945
5.789003
41.64
22
Sindora siamensis
23.20
3.877831
1.605819
6.767095
35.45
23 Litsea glutinosa 23.35 4.906418 1.307327 5.789779 35.35
24
Memecylon sp.
21.37
2.850456
1.717209
7.201149
33.13
25 Aporosa villosa 19.95 3.128594 1.438433 5.944953 30.46
26
Zizyphus
ii
19.32
4.165525
1.048171
4.627629

29.17
27
Macaranga
d il
18.91 3.119647 1.319896 5.509714 28.86
28 Schoepfia fragrans 16.47 2.825589 1.110127 4.607342 25.01
29
Symplocos

14.73
2.831356
0.903846
3.845152
22.32
30 Olea salicifolia 13.75 2.308386 0.942674 3.894101 20.89
31
Mimusops elengi
11.92
1.702117
0.913936
3.782743
18.32
32
Mitragyna
dif li
10.07 1.509527 0.749186 3.097539 15.43
33
Ampelocissus
i ii
10.10

1.576626
0.728916
2.996283
15.41
34 Garuga pinnata 9.48 2.067498 0.507796 2.241222 14.30
RUBBER THAI JOURNAL 1:1-18 (2012)
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14



Speci


Biomass Carbon
No.
Plant name
Stem
Branch
Leaf
Root
Total




kg/rai

35
Tristaniopsis

9.33
2.046373
0.495131
2.188198
14.06
36
Wendlandia tinctoria
8.48
1.632107
0.517077
2.172374
12.80
37
Garcinia sootepensis
8.05
1.482626
0.513043
2.142423
12.19
38
Phyllanthus emblica
7.27
1.0319
0.560606
2.328596
11.19
39

Garcinia merguensis
6.96
0.76074
0.621759
2.65883
11.00
40
Memecylon

5.91
0.761687
0.485036
2.040108
9.20
41
Macalanga

4.72
0.835322
0.310317
1.28797
7.15
42
Antidesma acidum
4.29
0.459364
0.386565
1.655269
6.79
43

Vitex pinnata
4.16
0.533183
0.344406
1.45627
6.50
44
Croton roxburghii
4.14
0.719539
0.276211
1.144493
6.28
45
Dalbergia oliverli
3.72
0.465895
0.307716
1.287903
5.78
46
Mitrephora

3.35
0.41526
0.279254
1.174734
5.21
47
Climber

3.41
0.503608
0.254642
1.048317
5.21
48
Catunaregam

3.27
0.387728
0.279796
1.182165
5.12
49
Vitex peduncularis
3.22
0.462529
0.249247
1.049682
4.98
50
Terminalia chebula
3.13
0.556321
0.205279
0.846819
4.74
51
Artocarpus lakoocha
3.04

0.394926
0.245748
1.022186
4.70
52
Hymenodictyon

2.54
0.432835
0.172317
0.707951
3.86
53
Garcinia cowa
2.48
0.346178
0.192603
0.796206
3.82
54
Lithocarpus elegans
2.42
0.322458
0.193775
0.807856
3.74
55
Bridelia affinis
2.02
0.218005

0.181855
0.777476
3.20
56
Antidesma

2.03
0.325214
0.14429
0.593563
3.09
57
Antidesma

1.88
0.258609
0.146922
0.609568
2.89
58
Colona floribunda
1.47
0.223648
0.107767
0.441944
2.24
59
Pavetta sp.
1.07
0.126832

0.090818
0.382454
1.67
60
Arytera littoralis
1.05
0.149422
0.080522
0.331418
1.61
61
Ochna intergerima
0.97
0.097822
0.089465
0.385513
1.54
62
Ilex umbellate
0.95
0.132458
0.073768
0.304108
1.46
63
Artabotrys vanprukii
0.95
0.132458
0.073768
0.304108

1.46
64
Rhus javanica
0.70
0.080549
0.061009
0.257741
1.10
65
Pavetta tomentosa
0.68
0.068917
0.063104
0.272269
1.09
66
Flacourtia indica
0.66
0.085662
0.053648
0.222815
1.02
67
Aganosma marginata
0.63
0.080849
0.05142
0.213808
0.98
68

Dalbergia cultrata
0.53
0.053749
0.048685
0.209951
0.84
69
Euodia roxburghiana
0.42
0.049628
0.035904
0.150928
0.66
70
Brucea javanica
0.34
0.031128
0.032739
0.143577
0.54
71
Anneslea fragrans
0.27
0.028497
0.023819
0.101587
0.42
72
Gnetum montanum
0.23

0.023896
0.020904
0.089593
0.36
73
Lepisanthes

0.19
0.016924
0.019258
0.085133
0.31
74
Bridelia affinis
0.19
0.018754
0.017462
0.075365
0.30
75
Mitragyna hirsuta
0.12
0.011257
0.011947
0.052357
0.20
76
Antidesma sp.
0.07
0.005441

0.00695
0.031164
0.11

Total
4,806.98
1,211.22
219.11
1,071.25
7,308.57

















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15

2. Carbon storages in soils
Accumulated carbon in the form of
organic matter is different between each age
group. Natural forest have organic matter of
57.81 Mg/ha, calculated to carbon level of
33.53 Mg/ha. In plantations aged 1, 5, 10, 15
and 20 years old, the level is at 37.37, 64.41,
49.37, 53.85 and 20.74 Mg/ha respectively.
With the average carbon in organic matter is
at 58 percent, the carbon level is calculated to
be 21.67, 37.36, 28.64, 31.23 and 12.03
Mg/ha respectively.
1 year old plantations have higher
carbon level than older plantations because of
the plowing that produces humus. For 5 years
old plantation, the level is lowest from the
erosion of the top soil. The carbon level
increases along with the age but 20 years old
plantations have low level, possibly due to the
originally low fertility level of the soil and
partly due to the top soil erosion.

Table 8. Biomass carbon storages in soils under rubber plantations and dry dipterocarp forest

Horizon Depth
Soil

Organic matter Org. Carbon

(cm)
(kg/m
2
)
(kg/rai)
(kg/ha)
(kg/rai)
(kg/ha)
1-year-old






Ap1
0-18
40.0
3,355.2
20,970.00
1,946.0
12,162.60
Ap2
18-40
70.0
1,261.6
7,884.80
731.7
4,573.18

Bt1
40-82/88
110.0
1,044.0
6,525.00
605.5
3,784.50
Btc1
82/88-100
70.0
318.0
1,987.50
184.4
1,152.75



5,978.8
37,367.30
3,467.7
21,673.03
5-year-old






Ap1
0-19

60.0
1,324.2
8,276.40
768.0
4,800.31
Ap2

19-36 70.0 1,239.8 7,748.60 719.1 4,494.19
Bt1

36-100 890.0 7,741.4 48,384.00 4,490.0 28,062.72



10,305.4
64,409.00
5,977.2
37,357.22
10-year-old






Ap1
0-19
50.0
1,498.1
9,363.20

868.9
5,430.66
Ap2
19-46
130.0
2,265.0
14,156.10
1,313.7
8,210.54
Bt1
46-100
450.0
4,136.8
25,855.20
2,399.4
14,996.02



7,899.9
49,374.50
4,582.0
28,637.21
15-year-old

Ap1
0-20
50.0
2,280.0
14,250.00
1,322.4
8,265.00
Ap2

20-40 50.0 1,088.0 6,800.00 631.0 3,944.00
Bt1

40-80 500.0 4,960.0 31,000.00 2,876.8 17,980.00
Bt2
80-100
60.0
288.0
1,800.00
167.0
1,044.00



8,616.0
53,850.00
4,997.3
31,233.00
20-year-old

Ap1

0-17
40.0
1,191.1
7,444.30
690.8
4,317.69
Ap2
17-40
20.7
417.3
2,608.20
242.0
1,512.76
Bt1
40-100
198.0
1,710.7
10,692.00
992.2
6,201.36



3,319.1
20,744.50
1,925.1
12,031.81
Dry dipterocarp forest

A 0-5 9.0 473.8 2,961.00 274.8 1,717.38
Bt1

5-18 59.4 1,701.2 10,632.60 986.7 6,166.91
Bt2
18-50
80.0
1,410.0
8,812.80
817.8
5,111.42
Bt3
50-100
590.0
5,664.0
35,400.00
3,285.1
20,532.00



9,249.0
57,806.40
5,364.4
33,527.71

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16

3. Ecosystem carbon storages
Accumulation of carbon level in the
ecosystem can be divided into two
types, the accumulation in biomass and
accumulation in soil. In natural forest,
the carbon level in the ecosystem
measures to 79.21 Mg/ha while in rubber
plantations aged 1, 5, 10, 15 and 20 years
measures to 22.54, 48.28, 55.32, 111.46
and 92.60 Mg/ha respectively.
The amount of carbon increases as
the biomass of the rubber trees increases
as they age. Younger plantations have high
ratio of carbon in the ground and decreases
as they age. The ratio of accumulation in
biomass also increases as they age.
However, 20 years old plantation has
lower carbon accumulation than 15 years
old plantation. The reason maybe the
inappropriate environment and some part
due to the different in management.


Table 9. Ecosystem carbon storages in rubber plantations and dry dipterocarp forest

Ecosystems
Biomass carbon
Soil carbon
Total
Mg/ha % Mg/ha % Mg/ha
1-year-old

0.87
3.00
21.67
97.00
22.54
5-year-old
10.92
22.00
37.36
73.00
48.28
10-year-old

26.68
48.00
28.64
52.00
55.32
15-year-old

80.23
70.00

31.23
30.00
111.46
20-year-old

80.57
87.00
12.03
13.00
92.60
Natural forest
45.68
57.00
33.53
43.00
79.21

Conclusion

Plantation in Phonpisai area was
dipterocarp forest, with original rock
formation as hard rock, siltstone and sandy
stone. Soil in dipterocarp forest is 5
centimeters thick. When turned into rubber
plantation, the plowing increases the
thickness to 15-20 centimeters. Original
top soil in dipterocarp forest is sandy clay
loam and bottom soil is clay soil. The soil
content and density has very little change
between plantation age groups. Soil

reaction in top and bottom soil is very
high. Organic matter in top soil is medium
to high. Available P is low. CEC is fairly
low to low. Base saturation is medium to
low. These properties do not vary between
age groups and are similar to natural
forest. As for the available K, the trend is
to increase in the top soil of older
plantations but still similar to natural
forest.
The density of the rubber tree has
some differentiation between age groups
with the value of 71-85 trees per rai. The
circumference increases as the trees age,
with plantations aged 1, 5, 10, 15 and 20
years old averaging 8.23, 29.42, 36.76,
53.54 and 54.45 centimeters respectively.
The average height averages 6.49, 8.83,
11.98, 15.41 and 14.46 centimeters and
diameter averaging 2.60, 4.80, 5.30, 6.40,
and 5.70 centimeters respectively. When
compared to the trees in the southern
region, the tree circumference and
available trees for harvest is lower.
Average biomass of rubber trees for
plantations aged 1, 5, 10, 15 and 20 years
old equals to 3.2, 43.0, 94.5, 278.8 and
264.9 kg/tree respectively. Biomass per
area averages 1.54, 19.10, 46.66, 140.56
and 140.73 Mg/ha respectively. Hence, the

biomass increases as the trees age with
highest rate between 1 to 15 years old and
slows down when 15 to 20 years old. The
ratio of biomass accumulation in each part
of the tree also changes as they age with
the branch increasing in biomass and
leaves and roots decreasing. When the
RUBBER THAI JOURNAL 1:1-18 (2012)
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17

trees are 20 years old, the biomass is 48.24
Mg/ha higher than dipterocarp forest.
Amount of accumulated carbon in biomass
of rubber plantation also increases by age
with the highest rate during 1 to 15 years
old and slows down during 15 to 20 years
old. Plantations aged 1, 5, 10, 15 and 20
years old have total carbon level of 0.87,
10.92, 26.68, 80.23 and 80.57 Mg/ha
respectively while dipterocarp forest only
have 45.68 Mg/ha Even if there is less
carbon stock in Nong Khai District
compared to those in eastern region, the
future bolds well when rubber trees in
Nong Khai grow and increase in size to
near carbon stock level of plantations in
the eastern region.
Phonpisai soil is usually covered with

dipterocarp foreset that have regular forest
fire during the dry season. The soil erosion
is also high with low level of water
absorption during rainy season. The soil is
very shallow and low in fertility.
Plantation of rubber tree in this soil for all
age groups, 1 to 20 years old, slowly
changes the soil property of the area.
However, the soil nutrient is also used by
the rubber trees as biomass at a higher rate
than natural forest, especially the
accumulation of carbon in biomass.
Even as the current growth of rubber
trees in the northeastern region is lower
than that of the southern region, mainly
due to the different environment and lower
soil fertility, the future of the northeastern
region as a major rubber plantation area is
possible. Support to the farmer to maintain
rubber trees in good quality is needed in
order to increase rubber growth rate to be
on par with southern region. Rubber
plantation in northeastern region will be an
important source for national carbon stock.
Other than helping with global warming,
the plantations will also help generation
income to the farmers and the country.
Plantations in the northeastern region of
around 0.45 million ha can serve as carbon
stock for 18.23 million metric tons. In the

future, the area has available plantation
area as high as 2.67 million ha that can be
utilized as important national carbon stock
and create value up to 10 billion Baht.

Acknowledgement

The authors would like to thank
Director General of Department of
Agriculture, Director General of Land
Development Department and Director of
Department of Plant Science and Natural
Resources, Faculty of Agriculture, Chiang
Mai University for chemical analysis of
plant and soil samples as well as Nongkai
Rubber Research Center staffs for
facilitate soil samples collection. Thanks to
students in Department of Plant Science
and Natural Resources, Faculty of
Agriculture, Chiang Mai University for
their help during soil sampling and
measuring rubber growths.

References

Bowen, G.D. and E. K.S. Nambiar. 1989.
Nutrition of Plantation Forests.
Academic Press, London, 505p.

Fisher, R.F. and D. Binkley. 2000.

Ecology and Management of Forest
Soils. John Wiley & Sons, Inc.,
489p.

Ogawa, H., K. Yoda, K. Ogino, and T.
Kira. 1965. Comparative ecological
study on three main types of forest
vegetation in Thailand. II. Plant
biomass. Nature and Life in
Southeast Asia. 4: 49-80.

Ogino, K., D. Ratanawongs, T. Tsutsumi
and T. Shidei. 1967. The primary
production of tropical forest in
Thailand. The Southeast Asian
Studies Vol. 5 (1): 122-154, Kyoto,
Japan.

Tsutsumi, T., K. Yoda, P. Sahunaru,
P.Dhanmanonda and B. Prachaiyo.
RUBBER THAI JOURNAL 1:1-18 (2012)
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18

1983. Forest: burning and
regeneration. In Shifting cultivation,
an experiment at Nam Phrom,
Northeast Thailand, and its
implications for upland farming in

the monsoon tropics. Kyuma, K and
Pairintra, C. (ed.). A report of a
cooperative research between Thai-
Japanese universities.

RUBBER THAI JOURNAL 1:19-31 (2012)
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Establishment of Standard Values for Nutritional Diagnosis
in Soil and Leaves of Immature Rubber Tree

Saichai Suchartgul
1
, Somsak Maneepong
2
, and Montree
Issarakrisila
2

1
Surat Thani Rubber Research Centre, Ta-Chana District, Surat Thani
Province, 84170,
2
School of Agricultural Technology, Walailak
University, Tha Sala, Nakhon Si Thammarat, Thailand 80160

ARTICLE INFO

Article history:
Revise: 1 January 2012
Revise: in revise
Presentation of IRRDB
Conference, 15-16
December 2011,
Changmai, Thailand
Accepted:
30 January 2012
Availabel online:
15 February 2012


Keywords:
rubber tree, standard
values, nutritional
diagnosis, leaf nutrient






ABSTRACT

Standard values for nutrient assessment are
required for integrated nutrient management (INM) of crop
production. The INM was used in order to maximize growth
or yield and sustain soil quality in the same time. This study
was aimed to establish standard values for immature rubber
tree. A nutrient survey was carried out during June - July
2009 in the east coast of Chumporn, Surat Thani and
Nakhon Si Thammarat provinces. The data were collected
from 43 farmers who grew rubber of the RRIM 600 variety.
The girths at 150 cm height of 4 year-old rubber were
measured in 100 trees from each plantation. Soil and leaves
were sampled in the area of girth measured trees. The
samples were analyzed for chemical properties and nutrient
concentrations. Correlations between the obtained values
and mean girths were fitting by a quadratic equation. The
result of tentative standard values revealed that the optimum
ranges for soil pH, base saturation, and exchangeable
acidity were 4.5 – 5.0, 25 - 75 % and 10 - 30 m mol (+)/kg
respectively. The optimum ranges for P (Bray 2), K (1 M
NH
4
OAc pH 7), Ca (1 M NH
4
OAc pH 7), S (0.01 M
KH
2
PO
4
), Fe (DTPA), Cu (DTPA), Zn (DTPA), and B (hot

0.01 M CaCl
2
) concentrations in soil were 10 - 20, 40 - 80,
50 - 600, 25 - 35, 30 - 90, 0.5 - 1.5, 0.5 - 1.5 and 0.3 - 0.7
mg/kg respectively. The optimum ranges for K/Mg, K/Ca
and Mg/Ca in soil were 2.0 - 6.0, 0.4 - 1.4 and 0.2 - 0.6
respectively. The optimum ranges for N, P, K, Ca, Mg and
S concentrations in leaves were 3.2 - 3.8, 0.25 - 0.30, 1.0 -
1.4, 1.0 - 1.5, > 0.35 and 0.2 - 0.3 % respectively, and for
Fe, Mn, Cu, and B were 90 - 130, 300 - 500, 10 - 15, and 40
- 80 mg/kg respectively. The optimum ranges for K/Mg,
K/Ca and Mg/Ca in leaves were 3.0 - 4.2, 0.8 - 1.4 and 0.3 -
0.5 respectively. The optimum ranges of CEC, Mg in soil,
Mn in soil and Zn in leaves were unable to establish.



RUBBER THAI JOURNAL 1:19-31 (2012)
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20
INTRODUCTION

Thailand is the largest natural
rubber producer, and produces the highest
mean yield as well. However, actual
productivity is still below the potential
yield of rubber plant. Thus, Thailand has
potential to increase productivity by

suitable nutrient management. Nujanart et
al. (2006) founded that fertilizer by the
farmers’ practices having an average
annual yield of 1,737 kg of dry
rubber/hectare, but if using the rates of
fertilizer recommendation of Rubber
Research Institute of Thailand (30-5-18,
recommended rate is 1 kg/tree/year), yield
was increased by an average of 1,894
kg/hectare/year. If increasing the rates of
fertilizer recommendation to 1.5
kg/tree/year, yield was increased by an
average of 2,100 kg/hectare/year. This
study showed that using fertilizer
recommendation for 3 consecutive years,
the concentration of phosphorus, calcium
and magnesium in rubber leaves dropped
significantly. So, the use of fertilizer in this
manner may not appropriate in the long
run.
Nutrient management aims to
achieve the highest yield of crops by
providing adequate supply of all plant
nutrient elements. It is difficult in
practicing since there are many factors
involved, as well as economic factors. The
use of fertilizers that contain only major
nutrient elements, plants have to obtain the
other plant nutrient elements from soil
alone. When the concentrations of those

elements are not meet the demand of plant,
the use of major nutrient elements alone
will not give benefit anymore. Thus, the
concept has shifted from fertilization to
integrated nutrient management to sustain
yield and maintain soil quality and prevent
deterioration (FAO, 2006). The integrated
nutrient management needs to know the
nutrient status in soil and plants, the ability
of plant nutrient uptake, and also the
nutrient removal, to adopt the balance of
nutrient. The standard values for assessing
nutrient status both in soil and in leaves are
essential. Recommendations for rubber
plant have been proposed (Thainugul,
1986; Pushparajah, 1977). However, the
values are not complete, and the analytical
methods are not widely used at the present.
Standard values can be developed
from the correlation between plant nutrient
concentration and tree performance or
yield. To create such a correlation, in the
case of short-lived plants can be carried out
by pot trials or field experiments by adding
different rates of nutrients (de la Puente
and Belda, 1999), but in the case of
perennial plants a nutrient survey method
is more favorable (Poovarodom &
Chatupote, 2002; Onthong et al., 2006;
Maneepong, 2008). Generally, nutrient

concentrations and girth or yield from the
survey do not correlate, because the growth
or yields have been affected by multiple
factors. Therefore, the analysis of
relationship commonly assumes that at the
concentration of any nutrient element, the
fields which have the best growth or most
productivity are the maximum potential
yields in the absence of any other limiting
factors and the rests are limited by another
variable. After selecting the maximum
yield at the increasing levels of each
nutrient then draw line to fit the boundary-
line curve. Boundary-line curve has
usually fitted models by eye (e.g. Webb,
1972) and commonly drawn the boundary-
line by hand (Schnug et al., 1996), or
fitting according to a statistical models,
such as linear regression ((Poovarodom &
Chatupote, 2002; Onthong et al, 2006;
Casanova et al., 2008), quadratic
polynomials (Schnug et al., 1995, 1996) or
splines (Shatar and McBratney, 2004). The
disadvantages of linear regression models
are: (1) the large number of observations
required, and (2) the construction of the
accurate boundary line (Van Erp and Van
Beusichem (1998). For this research,
authors have fitted boundary-line models by
quadratic equation.

RUBBER THAI JOURNAL 1:19-31 (2012)
Journal home page: www.rubberthai.com


21
MATERIALS AND METHODS

1. Sampling: A nutrient survey of
a RRIM 600 rubber clone at the age of 4
years from 43 farmer plantations in east
coast of upper part of southern Thailand
was carried out during June – July 2009.
Girths at 150 cm height were measured for
growth index for 100 trees from the
homogeneity area and space out at least
two rows from the edge. Soil and leaves
were sampled in a sub-plot of that area from
each plantation. Soil samples were collected
in X-cross shape for 9 holes/plantation
within a sup-plot, using a soil auger at the
depth of 0 - 30 cm. Soil samples were
mixed together and sampling again to make
a composite sample. Second and third
leaves were sampled at 3 - 5 months of age
from the terminal whorl of branches in the
canopy. Leaves were sampled from 12 – 15
trees/plantation and all samples were
mixed together to make a composite
sample.

2. Soil analysis: Soil samples
were air dried in the shade area, then
ground and sieved through a 2 mm sieve,
and analyzed for pH (soil : water = 1 : 2.5),
organic matter (OM; estimated from
organic carbon), available P (extracted with
Bray II solution and analyzed the
concentration by the molybdenum blue
method), available S (extracted with 0.01 M
KH
2
PO
4
and analyzed the concentration by
turbidimetry), exchangeable Ca, Mg, Na
and K (extracted with 1.0 M NH
4
OAc and
analyzed the concentration of Na and K by
flame photometry, Ca and Mg by atomic
absorption spectrophotometry) Fe, Mn Cu
and Zn (extracted with DTPA and analyzed
the concentration also by atomic absorption
spectrophotometry), available B (extracted
with 0.01 M CaCl
2
and analyzed the
concentration by azomethine-H method),
exchangeable acidity (EA; extracted with 1
M KCl and titrated with 0.01 M NaOH),

cation exchange capacity (CEC; calculated
from the summation of EA and
exchangeable Ca, Mg, Na and K) and base
saturation (BS; calculated from the
summation of exchangeable basic cations
divided by CEC) (Jones, 2001).
3. Leaves analysis: Leaves
samples were dried at 65 – 70 °C then
ground and sieved through 1 mm sieve,
and analyzed for N (Kjeldahl method), P,
K, Ca, Mg, S, Fe, Mn, Cu, Zn (digested
with HNO
3
: HClO
4
= 2 : 1, analyzed P by
vanadomolybdate method, K by flame
photometry, S by turbidimetry and Ca, Mg,
Fe, Mn, Cu and Zn by atomic absorption
spectrophotometry) and B (burned with
CaCO
3
, dissolved in 1 : 1 of HCl : water,
and analyzed the concentration by
azomethine-H method) (Tandon, 1995;
Jones, 2001).
4. Data processing: The scattered
plot diagrams were constructed between
mean girth and soil properties, or nutrient
concentrations both in soil and leaves.

Fitting the boundary-line curve with a
quadratic polynomial equation (Y = aX
2
+
bX + c). Outliers were removed on the
lower mean girth in order to explicit
influence of soil properties or nutrients.
Then calculated each predictor value that
resulting in maximum mean girth, using
the differential equation when the value of
the derivative is zero (0 = 2ax + b). A
range of soil properties or nutrient
concentrations resulted the mean girth at
high level, as classifying by Saichai et al.,
(2010), were selected as an optimum
range. And, then defined the values for
very low, low, high and very high range
categories. If the relationship was not
found after removal of the outliners. The
optimum range would be estimated from
the relationship between the concentration
of nutrients in soil and in leaves, or the
optimum range would be omitted.

RESULTES AND DISCUSSION

The result revealed that pH did
not correlate with mean girth. This might
mean that pH had no effect on the growth
of rubber tree significantly, or pH might be

block out from other prominent factors.
However, the result showed that pH
RUBBER THAI JOURNAL 1:19-31 (2012)
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22
correlated with BS. Therefore, the
optimum pH range could be derived from
the relationship between BS and mean
girth. The mean girth was highest at 50.7
% BS. The result indicated that rubber
plants prefer acidic soil (figure 1 and table
1). This result conforms with the
recommendation of Rubber Research
Institute of Thailand (2008) (pH 4.5 – 5.5),
and conforms with the studies of Sangsing
and Chaipanit (2009), which found that the
girth was negative linear relationship with
soil pH.
Mean girth responded to changing
of EA. The range of EA also covered the
optimum range. After removal of outliners
on the low data points, the optimum range
of EA should be 10 - 30 mmol(+)/kg
(figure 2 and table 1).
Samples used in this study had
CEC in a range of 7 – 97 mmol(+)/kg
which was in the rank of low to very low
as follow ranking of Thainugul (1986).

This range did not cover the optimum
range, and the growth of rubber still
responded to the increasing of CEC even if
the outliners were removed, and the data
points in some range was also discontinued
(figure 2). Therefore, an optimum range of
CEC was unable to establish.

y = -0.004x
2
+ 0.4052x + 22.735
R
2
= 0.2802
0
10
20
30
40
50
0 20 40 60 80 100 120
Base saturation (%)
Mean girth (cm)

y = 0.0081x + 4.3701
R
2
= 0.5503
4.0
4.5

5.0
5.5
6.0
0 20 40 60 80 100 120
Base saturation (%)
Soil pH


Figure 1 The relationship between BS and mean girth of rubber at 150 cm height (left), and the relationship
between BS and soil pH (right).

y = -0.026x
2
+ 0.9985x + 24.658
R
2
= 0.5148
0
10
20
30
40
50
0 10 20 30 40
Exchangeable acidity (mmol(+)/kg)
Mean girth (cm)

y = -0.0003x
2
+ 0.144x + 27.461

R
2
= 0.1862
0
10
20
30
40
50
0 20 40 60 80 100
CEC (mmol(+)/kg)
Mean girth (cm)


Figure 2 The relationship between EA (left) and CEC (right) with mean girth of rubber at 150 cm height.

RUBBER THAI JOURNAL 1:19-31 (2012)
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23
An optimum range of OM which
resulting maximum mean girth was 1.0 –
2.6 %. OM content did not cover the very
low and very high range, so it could be
classified only into low, optimum and high
(figure 3 and table 1). The optimum range
was nearly equal to the recommendation of
Rubber Research Institute of Thailand
(2008) (1.0 – 2.5 %).

Leaf N was in the range of 2.2 –
3.5 % which almost covered in low range
as follow the ranking of Thainugul (1986).
The result revealed that the optimum range
of N in leaves was 3.2 – 3.8 %, which was
nearly equal to the previous
recommendation (3.31 – 3.70 %)
(Pushparajah, 1977) (figure 3 and table 2).


y = -5.0314x
2
+ 18.52x + 17.42
R
2
= 0.4044
0
10
20
30
40
50
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Organic matter (%)
Mean girth (cm)

y = -4.5762x
2
+ 32.733x - 25.235
R

2
= 0.4528
0
10
20
30
40
50
2.0 2.5 3.0 3.5 4.0
N in leaves (%)
Mean girth (cm)


Figure 3 The relationship between OM (left) and N in leaves (right) with mean girth of rubber at 150 cm height.

Mean girths of rubber reached
maximum at 14.7 mg/kg of P in soil and
0.26 % of P in leaves. Rubber plant tended
to respond to P in soil up to 20 mg/kg.
Therefore, optimum range in soil should be
10 – 20 mg/kg and in leaves should be 0.25
– 0.30 % (figure 4, table 1 and 2).
Optimum range of P in soil was lower than
the previous recommendation (11 – 30
mg/kg) (Thainugul, 1986), but in leaves
was higher (0.20 – 0.25 %) (Pushparajah,
1977).
Mean girth declined when K in
soil was higher than 62 mg/kg, and K in
leaves was higher than 1.2 %. K in leaves

tended to respond to K in soil up to 80
mg/kg. Therefore, optimum range in soil
should be 40 – 80 mg/kg, and in leaves
should be 1.0 – 1.4 % (figure 4, table 1 and
2). The optimum range of K in soil was
lower than the generally recommendation,
recommendation of pomelos, and the
previous recommendation (Jones, 2003;
Somsak, 2008; Thainugul, 1986). It might
due to the influence of K-Mg antagonism.
The increasing of soil K decreased Mg
uptake by rubber plants. As a result, the
mean girth decreased (figure 6). This result
was similar to the result of Ologunde and
Sorensen (1982) (as cited in Fageria,
2009). They grew sorghum with various
levels of K and Mg in a sand culture
system, and found that K depressed the
concentration of Mg substantially in the
shoots, but the effect of Mg on K was a
slightly antagonistic effect or no effect at
all. Hannaway et al. (1982) (as cited in
Fageria, 2009), using solution culture,
found that increasing levels of K in
solution decreased the shoot concentration
of Mg in fescue. It can be deduced that
K/Mg imbalance retards rubber growth.
So, the use of K fertilizer and neglect Mg
may not appropriate for the growth of
rubber plant in the upper part of southern

Thailand. Pushparajah (1977) reported that
a RRIM 600 rubber clone did not respond
to K application when leaf K was higher
RUBBER THAI JOURNAL 1:19-31 (2012)
Journal home page: www.rubberthai.com


24
than 1.65 %, which was higher than the
result in this study. K in leaves in this
study might affected by the low Mg.
All soil samples used in this study
were acidic and had low Ca and Mg. The
concentrations of Ca did not cover the
optimum range even if the outliners were
removed, and rubber tends to respond to
the increasing of Ca in soil. As a result, Ca
in soil was unable to completely
establishment. The relationship between
mean girth and leaf Ca was found. Mean
girth was highest at 1.3 % Ca in leaves.
Therefore, an optimum range of Ca in
leaves should be 1.0 – 1.6 %. Ca in leaves
tended to respond to Ca in soil up to 350
mg/kg. Therefore, an optimum range of Ca
in soil should be 50 – 600 mg/kg, which
were in a wide range (figure 5, table 1 and
2). Hence, Ca may unessential to adding
because the increasing of Ca in soil had no
effect on Ca level in leaves. Similarly,

Pushparajah and Tan (1972) (as cited in
Lau and Wong, 1993) found that the
addition of Ca through application of
phosphate rock in normal or high rate on
leaf Ca content did not appear to be
significant. However, Ca is an essential
element for plant growth. Suntaree and
Jintana (2006) reported that Ca was the
most immobile in stem and branch of
rubber. They suggested that Ca should
adequately supply through the fertilizer
application scheme. Pushparajah (1977)
had proposed the optimum range of leaf Ca
for rubber should be 0.5 – 0.7 %, which
was lower than optimum range in this
study. It might be caused by take effect of
Ca on latex flow into consideration,
because excessive Ca can cause in stability
in the latex vessels resulting in early pre-
coagulation, thus reducing the time of flow
and yield. The concentrations of Mg in soil
did not cover the optimum range even if
the outliners were removed, and Mg in soil
did not correlate with Mg in leaves. As a
result, Mg in soil was unable to
establishment. The graph showed that Mg
in leaves did not cover the optimum range.
Therefore, an optimum range of Mg in
leaves should be more than 0.35 % (figure
6 table 2), which was higher than the

previous recommendation (0.20 – 0.25%)
(Pushparajah, 1977).

y = -0.0294x
2
+ 0.8662x + 28.177
R
2
= 0.1801
0
10
20
30
40
50
0 5 10 15 20 25 30
Available P in soil (mg/kg)
Mean girth (cm)

y = -0.0037x
2
+ 0.4616x + 19.957
R
2
= 0.3578
0
10
20
30
40

50
0 20 40 60 80 100 120
Exchangeble K in soil (mg/kg)
Mean girth (cm)

y = -696.11x
2
+ 368.35x - 14.224
R
2
= 0.4516
0
10
20
30
40
50
0.10 0.15 0.20 0.25 0.30
P in leaves (%)
Mean girth (cm)

y = -37.427x
2
+ 90.251x - 20.235
R
2
= 0.4888
0
10
20

30
40
50
0.5 0.7 0.9 1.1 1.3 1.5
K in leaves (%)
Mean girth (cm)

RUBBER THAI JOURNAL 1:19-31 (2012)
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25
y = -0.0001x
2
+ 0.0047x + 0.1912
R
2
= 0.19
0.10
0.15
0.20
0.25
0.30
0.35
0 5 10 15 20 25 30
Available P in soil (mg/kg)
P in leaves (%)

y = -7E-05x
2

+ 0.011x + 0.6989
R
2
= 0.2385
0.0
0.4
0.8
1.2
1.6
0 20 40 60 80 100 120
Exchangeable K in soil (mg/kg)
K in leaves (%)

Figure 4 The relationship between P in soil and mean girth at 150 cm height (top left), P in leaves and mean
girth at 150 cm height (middle left), P in soil and P in leaves (bottom left), K in soil and mean girth at
150 cm height (top right), K in leaves and mean girth at 150 cm height (middle right), and K in soil
and K in leaves (bottom right)

Sulfur both in soil and in leaves
were scattered in a wide range (figure 7).
After removal of the outliners, the result
showed that the optimum ranges in soil and
in leaves should be 25 – 35 mg/kg and 0.2
– 0.3 % respectively (table 1 and 2). The
optimum range in soils was higher than the
general recommendation (Jones, 2001) and
in leaves were higher than the previous
recommendation (Pushparajah, 1977) (0.20
– 0.25 %). Most S content in soil is in
organic compound, which must be

mineralized before it can be utilized for
plant. Thus, S which is extracted by 0.01
M KH
2
PO
4
that are mostly in SO
4
2-
form is
not directly related to the concentration in
leaves.

y = -1E-05x
2
+ 0.0137x + 29.119
R
2
= 0.0604
0
10
20
30
40
50
0 200 400 600 800
Exchangeable Ca in soil (mg/kg)
Mean girth (cm)

y = -15.386x

2
+ 40.477x + 6.9345
R
2
= 0.4668
0
10
20
30
40
50
0.5 1.0 1.5 2.0
Ca in leaves (%)
Mean girth (cm)

y = -4E-06x
2
+ 0.0028x + 0.8432
R
2
= 0.2517
0.0
0.5
1.0
1.5
2.0
2.5
0 200 400 600 800
Exchangeable Ca in soil (mg/kg)
Ca in leaves (%)

Figure 5 The relationship between Ca in soil (top left) and Mg in leaves (top right) with mean girth at 150 cm
height , and the relationship between Ca in soil and Ca in leaves (bottom)