RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com 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 ABSTRACT ARTICLE INFO Article history: Revise: 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 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 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 RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com 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 with areas suitable for rubber plantation of 340,606 It is also the province with most area used for rubber plantation in its region, coving 102,051 and also has remaining potential land use of 238,3994 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 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 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 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 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 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 are suitable for rubber plantation However, only 3.09 million ha, have yield more than 1,562 kilogram per per year and currently 0.45 million 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 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 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% RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com 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 mm by weighting method, and (3) particlesize 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 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 Growth and biomass of rubber Three samples are selected from five different age groups of plantations including year, 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 D2H 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) WS (trunk) WB (branhc) 1/WL (leaves) = = = Results and Discussion Growths Growth of rubber consists of the diameter, height and bush size which will differentiate between age groups Table 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, 189 (D2H)0.902 0.125 WS1.024 (1/WS0.9) + 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 RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com 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 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 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 years old plantations 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 inches or more for 10 years old plantations However, only 5.91% of 10 years old tress have diameter more than 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 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 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 years old plantation has average biomass of 19.10 Mg/ha Biomass from trunk, branch, leaves and roots equal RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com Fig 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 30 100 90 80 70 60 50 40 30 20 10 25 20 Rep.1 H (m) GBH (cm) Ponpisai Rep.2 Rep.1 15 Rep.2 Rep.3 Rep.3 10 5 10 15 20 10 15 20 Plantation ages (year s ) Plantation ages (year s ) Ponpisai 40,000 Biomass (kg/rai) 35,000 30,000 25,000 Rep.1 20,000 Rep.2 15,000 Rep.3 10,000 5,000 10 15 20 Plantation ages (year s ) Table Growths and biomass of para rubber in different age plantations on Phonpisai soil series Plantation age (years) 10 15 20 Plot No Mean Mean Mean Mean Mean Density (trees/rai) 79 78 77 78 71 71 71 213 80 79 78 237 86 77 79 242 85 86 84 255 GBH (cm) 8.86 + 1.97 7.69 + 1.56 8.13 + 2.22 8.23 + 1.99 31.92 + 4.86 30.86 + 5.33 25.50 + 5.39 29.42+ 5.89 34.79 + 9.12 34.60 + 6.66 40.96 + 7.23 36.76 + 8.26 50.92 + 10.63 52.23 + 11.77 57.67 + 11.25 53.54 + 11.54 54.90 + 11.20 53.05 + 8.89 55.44 + 10.65 54.45 + 10.30 Height (m) 6.57 + 0.83 6.53 + 0.69 6.36 + 0.70 6.49 + 0.75 8.86 + 0.30 8.84 + 0.39 8.78 + 0.41 8.83 + 0.37 12.04 + 1.45 12.03 + 1.26 11.87 + 1.17 11.98 + 1.30 15.34 + 0.93 15.34 + 0.66 15.55 + 0.61 15.41 + 0.76 15.07 + 1.58 14.22 + 1.18 14.08 + 1.14 14.46 + 1.38 Crown width (m) 2.70 + 0.20 2.60 + 0.20 2.60 + 0.20 2.60 + 0.20 5.10 + 0.80 5.20 + 0.80 4.10 + 0.80 4.80 + 0.90 4.80 + 0.60 5.20 + 0.80 5.90 + 0.60 5.30 + 0.80 6.60 + 1.60 7.20 + 1.50 6.40 + 1.60 5.70 + 1.60 5.70 + 1.40 5.70 + 1.40 5.70 + 1.40 5.70 + 1.40 Biomass (kg/tree) 3.6 2.8 3.1 3.2 50.0 46.8 33.3 43.0 87.6 81.7 114.5 94.5 246.7 263.4 328.7 278.8 284.1 244.1 266.8 264.9 RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com Table Biomass of para rubber in different age plantations on Phonpisai soil series Plantation age (years) Plot No Density Tree/rai 1 Mean % Mean % Mean 79 78 77 78 10 15 20 Mean % Mean % 71 71 71 71 80 79 78 79 % 86 77 79 81 85 86 84 85 Ws Wb Biomass (kg/rai) Wl Wr Total 116.7 88.7 97.0 100.8 40.84 1,297.9 1,222.9 874.1 1,131.6 37.03 2,303.1 2,203.8 2,898.9 2,468.6 33.07 5,947.2 5,592.4 6,875.0 6,138.2 27.29 6,584.9 5,933.2 6,208.3 6,242.2 27.72 26.4 17.3 20.9 21.5 8.73 1,115.6 1,025.1 621.9 920.9 30.13 2,810.0 2,417.4 3,695.4 2,974.3 39.84 10,789.2 10,505.6 14,037.3 11,777.4 52.37 12,665.6 10,584.5 11,551.8 11,600.6 51.52 45.1 37.4 39.0 40.5 16.41 225.5 216.1 171.3 204.3 6.69 339.9 332.5 399.3 357.3 4.79 668.6 617.7 719.3 668.56 2.97 714.3 670.4 685.4 690.0 3.06 96.4 74.7 80.8 83.9 34.02 909.8 860.2 627.9 799.3 26.15 1,557.9 1,500.2 1,936.8 1,665.0 22.30 3,808.8 3,568.0 4,338.7 3,905.1 17.36 4,186.4 3,805.0 3,961.9 3,984.4 17.70 284.5 218.1 237.8 246.8 100 3,548.8 3,324.3 2,295.3 3,056.1 100 7,010.9 6,453.9 8,930.5 7,465.1 100 21,213.8 20,283.7 25,970.3 22,489.3 100 24,151.2 20,993.1 22,407.4 22,517.3 100 Total Biomass (Mg/ha) 1.78 1.36 1.49 1.54 22.18 20.78 14.35 19.10 43.82 40.34 55.82 46.66 132.59 126.77 162.31 140.56 150.95 131.21 140.05 140.73 Mg.m-3) and bottom soil has low to high density Soil of 1, 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 Changes in Soil Characteristics with Plantation Ages Physical and chemical properties of the soil are shown in Table and Table 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, and 10 years old plantations have sandy clay loam to clay and and 15 years old plantation have sandy clay loam to clay soil 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 Bulk density: The top soil of natural forest has medium density (1.52 RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com 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 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 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 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 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 (100110 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 RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com Table 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 Mg m sand silt clay (%) 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 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 1-year-old Ap 5-year-old 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 0-19 43.52 12.00 44.48 50.56 2.20 2.55 10-year-old Ap 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 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 15-year-old 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 0-17 66.80 12.00 21.20 14.49 1.33 2.39 20-year-old Ap 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 RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com Table Soil physical properties under different age rubber plantations and adjacent dry dipterocarp forest on Ponpisai soil series Horizon Particle size distribution (%) Depth (cm) Gravel Bulk density Particle density Mg m sand silt clay (%) 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 Soil chemical properties under different age rubber plantations and adjacent dry dipterocarp forest on Ponpisai soil series Horizo Depth (cm) 1-year-old Ap 0-18 Btcv1 18-40 Btcv2 40-82/88 Btv 82/88-135/158 BCv1 135/158-190 BCv2 190-210+ 5-year-old Ap 0-19 Btcv1 19-36 Btcv2 36-110 Btcv3 110-143 BCv1 143-182 BCv2 182-210+ 10-year-old Ap 0-19 Btcv1 19-46 Btcv2 46-92/101 Btcv3 92/101-135 BCv1 135-182 BCv2 182-210+ 15-year-old Ap 0-20 Btc1 20-40 Btc2 40-80 Btv3 80-100 2Btv4 100-140 2BCv1 140-180 2BCv2 180-210+ 20-year-old Ap 0-17 Btcv1 17-40 Btcv2 40-107 BCv1 107-145 BCv2 145-185 BCv3 185-203+ Dry dipterocarp forest A 0-5 BA 5-18 Btcv1 18-50 Btcv2 50-98 Btv 98-154 BCv 154-210+ pH OM C g/kg N 4.9 5.0 4.6 4.7 4.7 4.5 46.6 11.2 5.8 2.5 1.8 2.0 27.02 6.49 3.36 1.45 1.04 1.16 1.93 0.78 0.25 0.13 0.10 0.10 1 83 82 77 100 110 193 7.6 7.7 8.2 14.4 15.1 15.6 1.92 4.14 4.53 12.12 13.55 13.60 51.40 22.12 21.96 6.82 5.25 8.11 4.7 4.6 4.8 4.9 4.9 4.8 12.1 10.6 5.4 1.7 2.7 2.5 7.01 6.14 3.13 0.98 1.56 1.45 0.72 0.73 0.35 0.10 0.10 0.10 1 47 69 62 63 83 80 4.1 5.1 6.3 3.3 7.4 7.0 2.07 3.15 3.65 2.27 5.76 5.76 26.79 22.37 19.51 25.54 13.72 13.04 5.0 4.9 5.0 5.0 4.9 4.7 17.6 10.7 5.7 5.0 5.0 3.9 10.20 6.20 3.30 2.90 2.90 2.26 1.29 0.74 0.29 0.10 0.10 0.10 1 1 86 88 88 61 77 80 7.1 7.8 6.9 6.1 8.3 9.6 3.55 4.19 3.35 3.01 5.67 6.50 24.12 17.81 19.99 22.78 13.32 9.23 4.8 4.8 4.8 4.7 4.7 4.6 4.7 28.5 13.6 6.2 3.0 3.0 1.3 1.7 16.53 7.88 3.59 1.74 1.74 0.75 0.98 1.10 0.71 0.37 0.27 0.10 0.10 0.10 1 1 1 100 87 103 85 109 121 105 6.4 8.6 8.8 10.9 14.0 11.4 11.6 2.41 5.62 5.12 8.77 11.68 9.90 10.69 35.10 14.36 19.69 7.26 5.37 5.29 4.62 4.8 4.8 4.9 4.9 4.9 4.6 15.1 12.6 5.4 2.7 2.0 1.7 8.75 7.30 3.13 1.56 1.16 0.98 0.88 0.58 0.38 0.10 0.10 0.10 1 1 110 57 44 44 36 36 3.6 5.2 7.3 7.3 6.9 6.3 2.07 3.30 5.08 5.86 5.42 5.76 24.75 10.56 13.48 7.14 6.50 6.00 5.0 4.7 4.7 4.7 4.8 4.6 32.9 17.9 10.2 6.0 3.0 3.7 10.08 10.38 5.91 3.48 1.74 2.14 1.80 1.06 0.64 0.26 0.18 0.17 110 97 113 113 120 128 7.7 12.6 16.9 17.2 18.4 19.0 1.63 8.03 13.25 14.18 15.47 15.47 70.10 26.27 17.79 14.84 13.30 15.48 Avail Avail mg/kg CEC EA cmol /kg BS % RUBBER THAI JOURNAL 1:1-18 (2012) Journal home page: www.rubberthai.com 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 and 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 Carbon Stocks in Para Rubber Plantations and Natural Forest 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 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 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 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 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 10 RUBBER THAI JOURNAL 1:19-31 (2012) Journal home page: www.rubberthai.com 1.6 0.35 K in leaves (%) P in leaves (%) 0.30 0.25 0.20 y = -0.0001x + 0.0047x + 0.1912 R2 = 0.19 0.15 1.2 0.8 0.4 y = -7E-05x + 0.011x + 0.6989 R2 = 0.2385 0.0 0.10 10 15 20 25 Available P in soil (mg/kg) 30 20 40 60 80 100 Exchangeable K in soil (mg/kg) 120 Figure 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 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 KH2PO4 that are mostly in SO42- form is not directly related to the concentration in leaves 50 40 40 Mean girth (cm) Mean girth (cm) 50 30 20 y = -1E-05x + 0.0137x + 29.119 R2 = 0.0604 10 30 20 y = -15.386x + 40.477x + 6.9345 R2 = 0.4668 10 0 0.5 200 400 600 800 Exchangeable Ca in soil (mg/kg) 1.0 1.5 Ca in leaves (%) 2.0 Ca in leaves (%) 2.5 2.0 1.5 1.0 y = -4E-06x + 0.0028x + 0.8432 R2 = 0.2517 0.5 0.0 200 400 600 Exchangeable Ca in soil (mg/kg) 800 Figure 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) 25 RUBBER THAI JOURNAL 1:19-31 (2012) Journal home page: www.rubberthai.com 0.5 Mg in leaves (%) Mean girth (cm) 50 40 30 20 y = -148.48x + 135.8x + 3.6214 R2 = 0.4314 10 0.4 0.3 0.2 y = -0.0008x - 0.0042x + 0.3228 R2 = 0.1268 0.1 0.0 0.1 0.2 0.3 0.4 Mg in leaves (%) 0.5 K/Mg in soil (mg/kg) 10 Figure The relationship between Mg in leaves and mean girth at 150 cm height (left), and the relationship between K/Mg in soil and Mg in leaves (right) 40 Mean girth (cm) 50 40 Mean girth (cm) 50 30 20 y = -0.0427x + 2.4869x - 3.6747 R2 = 0.2269 10 30 20 10 y = -465.44x + 235.54x + 4.0226 R2 = 0.548 0 15 20 25 30 35 Available S in soil (mg/kg) 0.10 0.15 0.20 0.25 0.30 0.35 0.40 S in leaves (%) 40 Figure The relationship between S in soil (left) and S in leaves (right) with mean girth at 150 cm height 500 mg/kg), so it might be further studies on Mn The result showed that the optimum ranges of Cu and Zn in soil were the same (0.5 – 1.5 mg/kg), which were higher than the recommendation of Rubber Research Institute of Thailand (2008) (0.4 – 0.6 and 0.8 – 1.0 respectively) Pushparajah (1977) suggested that the desired levels for Cu and Zn in leaves were 10 and 20 mg/kg respectively, which Cu was similar to the result in this study while Zn unable to established (table and 2) Most of the samples used in this study had low Cu and Zn It was probably due to the parent materials are alike Thus, the adding of these micronutrients might be improved the growth of rubber in the upper part of southern Thailand Soil samples used in this study had B in a range of 0.14 – 0.61 mg/kg which were Soil samples used in this study had Fe and Mn in the ranges of 13.5 – 97.5 and 0.5 – 332 mg/kg respectively which were in a wide range The result revealed that an optimum range of Fe in soil should be 30 – 90 mg/kg, as Mn was unable to establish (figure table 1) An optimum range of Fe in soil was higher than the general recommendation (Jones, 2003) and higher than the recommendation of Rubber Research Institute of Thailand (2008) too (30 – 35 mg/kg) Pushparajah (1977) suggested that the optimum ranges of Fe and Mn in leaves should be 60 – 80 and 45 – 150 mg/kg respectively while the results in this study were 80 – 140 and 300 – 500 mg/kg respectively (figure table 2) Rubber may not require such high values These high levels of Mn may be toxic to the rubber (> 26 RUBBER THAI JOURNAL 1:19-31 (2012) Journal home page: www.rubberthai.com The result revealed that K/Mg and K/Ca ratio in soil did not correlate with leaf K concentration, but correlated with leaf Mg and leaf Ca concentration respectively (figure and 9) Therefore, the K fertilizer recommendation without Mg and Ca application might lead to insufficiency of these elements in the long run The result showed that the rubber growth was related to Mg/Ca than Ca/Mg Thus, the ratio of Mg/Ca should be established instead of Ca/Mg Mg/Ca in soil did not correlated with leaf Mg concentration, but correlated with leaf Ca concentration (figure 9) So, the addition of Mg without Ca could decreased Mg uptake in rubber plant The result revealed that the optimum ranges of K/Mg, K/Ca and Mg/Ca in soil should be 2.0 – 6.0, 0.4 – 1.4 and 0.2 – 0.6 respectively The optimum ranges of K/Mg, K/Ca and Mg/Ca in leaves should be 3.0 – 4.2, 0.8 – 1.4 and 0.3 – 0.5 respectively low to medium for general plants The result revealed that rubber plant tended to respond to higher B level in soil than these The optimum range in soil was 0.3 – 0.7 mg/kg which was similar to the general recommendation (Jones, 2003) Pushparajah (1977) suggested that the desired level for B in leaves was 15 mg/kg, as in this study, the optimum range should be 40 - 80 mg/kg which was very different (table and 2) However, these values were slightly higher than the optimum range of B in leaves for tropical fruit crops, such as longkong (Onthong et al., 2007) and rambutan (Lim et al., 1997) Mengel and Kirkby (1987) said that dicotyledons which composes of latex often requires higher B than monocotyledons Therefore, the optimum range of B in rubber leaves in this study was not likely to be wrong (table and 2) 50 40 40 mean girth (cm) Mean girth (cm) 50 30 20 y = -0.0043x + 0.4966x + 19.871 R2 = 0.3897 10 30 20 0 20 40 60 80 Extractable Fe in soil (mg/kg) 100 60 40 80 100 120 140 160 Fe in leaves (mg/kg) 180 50 40 Mean girth (cm) 50 Mean girth (cm) y = -0.0029x + 0.6502x - 1.8174 R2 = 0.1937 10 30 20 y = -0.0001x + 0.0439x + 29.44 R2 = 0.0585 10 30 20 y = -9E-05x + 0.0778x + 16.467 R2 = 0.4953 10 0 0 100 200 300 400 Extractable Mn in soil (mg/kg) 100 200 300 400 500 600 700 Mn in leaves (mg/kg) Figure The relationship between Fe in soil (top left) and Fe in leaves (top right) with mean girth at 150 cm height, Mn in soil (bottom left) and Mn in leaves (bottom right) with mean girth at 150 cm height 27 RUBBER THAI JOURNAL 1:19-31 (2012) Journal home page: www.rubberthai.com 2.5 Ca in leaves (%) Ca in leaves (%) 2.5 y = 0.2004x - 0.7237x + 1.3864 R2 = 0.3829 2.0 1.5 1.0 0.5 y = 3.8496x - 3.2321x + 1.5695 R2 = 0.3243 2.0 1.5 1.0 0.5 0.0 0.0 0.0 0.5 1.0 1.5 K/Ca in soil (mg/kg) 0.0 2.0 0.1 0.2 0.3 0.4 0.5 Mg/Ca in soil (mg/kg) 0.6 Figure The relationship between K/Ca in soil and Ca in leaves (left) and the relationship between Mg/Ca in soil and Ca in leaves (right) The quadratic polynomial model that used in these studies had some limitation like the other models The precision of standard values depended on the amount and distribution of data points The narrow range of soil properties or soil- leaf nutrient concentration had been hardly to complete the standard values for all levels However, these results would help in improving the standard values in interpreting the soil and leaf analysis for assessing fertilizer needs in rubber plant Table Tentative standard values derived from the boundary line approach for nutritional diagnosis in soil at – 30 cm depth Ranking Chemical soil properties unit (analyzed method) Very low Low Optimum High Very high pH (1:2.5 in water) BS (calculate) % < 4.5 4.5 - 5.0 > 5.0 - - < 25 25 - 75 75 - 100 > 100 CEC (calculate) EA (1 M KCl) unable to establish mmol(+)/kg - < 10 10 - 30 > 30 - % - < 1.0 1.0 – 2.6 > 2.6 - P (Bray II) mg/kg 30 K (1 M NH4OAc pH7) mg/kg < 20 20 - 40 40 - 80 80 - 120 > 120 Ca (1 M NH4OAc pH7) mg/kg - < 50 50 - 600 > 600 - Mg (1 M NH4OAc pH7) mg/kg S (0.01 M KH2PO4) mg/kg < 15 15 - 25 25 - 35 > 35 - Fe (DTPA) mg/kg - < 30 30 – 90 > 90 - Mn (DTPA) mg/kg Cu (DTPA) mg/kg - < 0.5 0.5 - 1.5 > 1.5 - Zn (DTPA) mg/kg - < 0.5 0.5 - 1.5 > 1.5 - B (hot 0.01 M CaCl2) mg/kg - < 0.3 0.3 - 0.7 > 0.7 - OM (Walkley&Black) unable to establish unable to establish K/Mg - < 2.0 2.0 – 6.0 > 6.0 - K/Ca - < 0.4 0.4 - 1.4 > 1.4 - Mg/Ca - < 0.2 0.2 - 0.6 > 0.6 - 28 RUBBER THAI JOURNAL 1:19-31 (2012) Journal home page: www.rubberthai.com Table Tentative standard values derived from the boundary line approach for nutritional diagnosis in leaves, sampling the second or third leaves at 3-5 months of age from the terminal whorl of branches in canopy Ranking Nutrient elements Unit Very low Low Optimum High Very high N % < 2.6 2.6 - 3.2 3.2 – 3.8 > 3.8 - P % < 0.20 0.20 - 0.25 0.25 - 0.30 > 0.30 - K % < 0.7 0.7 - 1.0 1.0 - 1.4 > 1.4 - Ca % < 0.5 0.5 - 1.0 1.0 - 1.5 > 1.5 - Mg % < 0.25 0.25 - 0.35 > 0.35 - - S % < 0.1 0.1 - 0.2 0.2 - 0.3 0.3 - 0.4 > 0.4 Fe mg/kg < 50 50 - 90 90 – 130 130 - 170 > 170 Mn mg/kg < 200 200 - 300 300 - 500 > 500 - Cu mg/kg 15 - Zn mg/kg B mg/kg unable to establish < 10 10 - 40 40 - 80 > 80 - K/Mg - < 3.0 3.0 – 4.2 > 4.2 - K/Ca - < 0.8 0.8 - 1.4 > 1.4 - Mg/Ca - < 0.3 0.3 - 0.5 > 0.5 - CEC, Mg in soil, Mn in soil and Zn in leaves were unable to establish The quadratic polynomial equations as mathematical models for fitting the boundary line can be used to establish the standard values These models did not require the large number of observations in comparison with other models The data covering only one side of the optimum range was enough to establish the standard values Beside, an advantage of this model is that, it is neither to know the real data scope on the boundary line nor remove a large number of data points In addition, the data was equally emphasized both in the higher side and lower side of optimum range This method can also reduce bias from the researchers The results in this study would help in improving the standard values in interpreting the soil and leaf analysis for assessing fertilizer needs in rubber plant CONCLUSIONS The optimum ranges for soil pH, base saturation, and exchangeable acidity were 4.5 – 5.0, 25 - 75 % and 10 – 30 mmol(+)/kg respectively The optimum ranges for P (Bray 2), K (1 M NH4OAc pH 7), Ca (1 M NH4OAc pH 7), S (0.01 M KH2PO4), Fe (DTPA), Cu (DTPA), Zn (DTPA), and B (hot 0.01 M CaCl2) 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 29 RUBBER THAI JOURNAL 1:19-31 (2012) Journal home page: www.rubberthai.com from genetic engineering to field practice (pp 281-283) Kluwer Academic Publishers: Cochin, India Lim, T.K., L Luders, Y Diczbalis and M Poffley 1997 Rambutan nutrient requirement and management Department of Primary Industry and Fisheries Maneepong, S 2008 A nutrient survey for establishment of standard recommendation of soil and plant analysis for pomelo Agricultural Sci J 37(3):62-65 Nujanart Kungpisdan, Rasamee Suravanit, Wanpen Prukwiwat, Sumet Prukwarun and Anusorn Ramlee 2006 Development of technology in fertilizer utilization to increase yield of rubber Thai Agricultural Research Journal 24(2):112-131 Ologunde, O O and R.C Sorensen 1982 Influence of K and Mg in nutrient solutions on sorgum Agron J 74:41-46 Onthong, J., S Gimsanguan, and P Tiraphat 2006 Stand values of nitrogen, phosphorus, potassium, calcium and magnesium in longkong leaf Agricultural Sci J 37(3):257268 Onthong, J., P Tirapat, and K, Sukmee 2007 Tentative standard concentration values of iron, manganese, zinc, copper and boron in Longkong (Aglaia dookkoo Griff.) Leaf Songklanakarin J Sci Technol 29(2):287-296 Poovaradom S and W Chatupote 2002 Boundary line approach in specifying durian nutrient standards Poster presentation at 17th World Congress of Soil Science 14-21 August 2002, Bangkok, Thailand Pushparajah, E and K.T Tan 1972 Proc Rubb Res Inst Malaya Pla’s Conf Kuala Lunpur 1972 p.140 Pushparajah, E 1977 Nutrition and fertilizer use in Hevea and associated covers in Peninsular Malaysia A review: Quarterly Journal Rubber ACKOWLEDGEMENTS We are very grateful thank to rubber growers for the cooperation We would like to thank the official of Surat Thani Rubber Research Centre for assistance with sample collection and thank Rubber Replanting Aid Fund in the studied area for supporting the data of rubber growers This study was supported by Walailak University Fund REFERENCES Casanova, D., J Goudriaan, J Bouma and G.F Epema 1999 Yield gap analysis in relation to soil properties in direct-seeded flooded rice Geoderma 91:191-216 de la Puente, L.S and R.M Belda 1999 Square root and quadratic equation for the study of leaf diagnosis in wheat Journal of Plant Nutrition 22:1469-1479 FAO 2006 Plant Nutrition for Food Security: A guide for integrated nutrient management Food and Agriculture Organization of the United Nation: Rome P.141-192 Jones, J.B 2001 Laboratory guide for conducting soil test and plant analysis CRC Press: New York Jones, J.B 2003 Agronomic Handbook: Management of crops, soils, and their fertility CRC Press: New York Mengel, K and E.A Kirkby 1987 Principles of plant nutrition International Potass Institute: Bern p.559-572 Fageria, N.K 2009 The use of nutrients in crop plants CRC Press: New York Hannaway, D.B., L.P Bush, and J.E Leggett 1982 Mineral composition of Kenhytall fescue as affected by nutrient solution concentration of Mg and K J Plant Nutr 5:137-151 Lau, C.H and C.B Wong 1993 Collection of leaf nutrient values for assessment of Hevea nutrition In N.J Barrow (ed.), Plant nutrition – 30 RUBBER THAI JOURNAL 1:19-31 (2012) Journal home page: www.rubberthai.com Van Erp, Peter.J and Marinus L Van Beusichem 1998 Soil and plant testing programs as a tool for optimizing fertilizer strategies In Z Rengel (Ed.), Nutrient use in crop production (pp 53-75) Food Products Press: New York Webb, R.A 1972 Use of the boundary line in the analysis of biological data Journal of Horticultural Science 47:309-319 Research Institute of Sri Lanka 54:270-283 Rubber Research Institute of Thailand 2008 The use of fertilizers based on soil and leaf analysis Rubber Research Institute of Thailand: Bangkok p.9 (in Thai) Saichai Suchartgul, Somsak Maneepong and Montree Issarakraisila 2010 Fertilizer usage and growth of immature rubber in Chumporn, Surat Thani, and Nakhon Si Thammarat Provinces Thai Journal of Soils and Fertilizers 32(3):180-197 Schnug, E., J Heym and D.P Murphy 1995 Boundary line determination technique (BOLIDES) In P.C Robert, R.H Rust & W.E Larson (Eds.), Site-Specific Management for Agricultural Systems Madison, WI: ASA-CSSA-SSSA P.899-908 Schnug, E., J Heym and F Achwan 1996 Establishing critical values for soil and plant analysis by means of the boundary line development system (Bolides) Communications in Soil Science and Plant Analysis 27:27392748 Shatar, T.M and A.B McBratney 2004 Boundary-line analysis of field-scale yield response to soil properties Journal of Agricultural Science 142:553-560 Sungsing, K and P Chaipanit 2009 The chemical properties of soil and leaf chlorophyll concentration on the growth of immature rubber in non traditional area Para Rubber Bulletin 30(1):35-60 (in Thai) Tandon, H.L.S ed 1995 Methods of analysis of soils, plants, waters and fertilisers Fertiliser development and consultation oganisation: New Delhi Thainugul, W 1986 Soil and Leaf analysis as a basis of fertilizer recommendations for Hevea brasilliensis in Thailand D Sc Thesis, University of Ghent, Belgium 31 RUBBER THAI JOURNAL 1: 32-39 (2012) Journal home page: www.rubberthai.com Modification of Asphalt Cement by Natural Rubber for Pavement Construction Nopparat Vichitcholchai* , Jaratsri Panmai* and Nuchanat Na-Ranong* * Rubber Products Industry Group, Post-harvest and Product Processing Research and Development Office, Department of Agriculture, Ministry of Agriculture and Co-operatives, Bangkok, Thailand 10900 Abstract ARTICLE INFO Article history: Revise: January 2012 Revise: in revise International Rubber Conference 2005, 24-25 October 2005, Yokohama Japan Accepted: 12 January 2012 Available online: January 2012 Improvement the quality of asphalt for pavement construction is practical to prolong lifetime of roads Polymer Modified Asphalt or PMA is one of such improvement by mixing polymers in asphalt Natural rubber is an interested polymer that can be efficiently used The distingue quality of natural rubber is its’ high stability, elasticity, and fatigue resistance The aim of the study is to find the appropriate ratio of asphalt and rubber, which can achieve specifications required The experiments were carried on by adding Ribbed Smoked Sheet (RSS) of 0, 2, 4, 6, and10% by weight in asphalt and using high shear mixer Asphalt qualities were investigated in penetration, softening point, penetration index, ductility, torsional recovery, toughness-tenacity, and viscosity It was found that 6% by weight of natural rubber in asphalt is the most effective ratio to develop low penetration, high softening point, high penetration index, high torsional recovery, and high toughness - tenacity The road using this mixing rate shows high strength and resistance, whilst increasing of viscosity does not cause the problem in aggregation of asphalt-concrete RUBBER THAI JOURNAL 1: 32-39 (2012) Journal home page: www.rubberthai.com Mathew, N.M., Thomas, S., Chatterjee, P and Siddqui, Ma (1992) had studied on improvement asphalt properties using fumigated rubber to reduce molecule by dissolving rubber into Fluxing oil until it became to Liquid Natural Rubber, LNR, and had been mixed with asphalt cement by heating Two kinds of asphalt cements were investigated those are penetration grade and blown grade Another factor was the ratio of rubber to asphalt used to mix The properties experimented were penetration, ductility, softening point and viscosity It was found that adding LNR provided reduction of ductility and increased the softening point On the other hand, Fermando, M.J Nadarajah, M (1992) had carried on improvement asphalt properties by various kinds of natural rubber latex such as field latex, concentrated latex, and skim latex They used heating mixture method by spraying natural rubber latex into asphalt at the Introduction Road construction is currently paved with asphalt owing to its good flexibility apart from the price that is lower than that of concrete Materials for asphalt paving and standard structures must be complied with the requirements of standard specified by Highway Department in order to be sure that it’s suitable to utilize and last long whilst highly safe for the users However, asphalt paving roads shows limitation on temperature, soften when the temperature is high and cracked when the temperature is low In addition, hard traffic and high loading weight will damage the roads earlier than usual and cause expenses to repair and maintenance Therefore, it is necessary to improve the quality of asphalt by the material which can play the role as a binder to achieve the following properties ; increasing viscosity and elasticity diminution of temperature susceptibility higher softening point and aging resistance ameliorate of cohesion O temperature of 300 - 325 C and stirring continuously for 20 minutes after adding natural rubber latex The results showed the same tendency that the penetration value had been reduced whilst the softening point was increased Shelburne, T.E and Sheppe, RL used powdered natural rubber, powdered reclaimed rubber mixed into asphalt The properties studied were the nature of road surface compare to the roads of natural asphalt constructed by the agency of Virginia State (Virginia Department of Highway) The visual observations on damaged area showed that the road surface improved with polymer had less rough and crack However, it took for years to investigate the difference between the road surface improved with powdered natural rubber and that of non-improvement with natural rubber The improvement of asphalt to have those properties with various methods is continually carried on, and the practical one is using polymers to mix in asphalt that is called “Polymer Modification Asphalt” Rubber is a kind of polymers using for modifying the asphalt properties Some properties that are advantages such as stability, elasticity and fatigue resistance will be the better supplementary to asphalt properties and to extend aging of roads which can be help to save budget of maintenance One of polymers used to improve asphalt property is Styrene Butadiene Styrene, SBS Mixing asphalt with rubber has been testing for a long time Nair, N.R., 33 RUBBER THAI JOURNAL 1: 32-39 (2012) Journal home page: www.rubberthai.com The study in the past provided a useful technical information that rubber is an interested polymer mixing with asphalt to improve its properties resulted extending of the durability of roads In addition, as Thailand is a biggest producing country of natural rubber, it is a good opportunity to increase amount of NR domestic consumption Therefore, it is reasonable to study on suitable kind of rubber, ratio mixed in asphalt, and mixture technique degree and left for 30 minutes then measure degree of recovery Toughness-tenacity - the toughness means energy used to make test piece broken completely under the force - Tenacity means work provided from maximum force to tear the sample The test is made by sinking halfcircle head of test equipment into the sample and stretch with constant velocity of 500 ± mm per minute until the sample torn separately from each other, record value of force and elongation Viscosity value measured with Experiments Masticate RSS with two-roll mill O O at the temperature of 70 C for 30 minutes, then cut into small pieces Add them to asphalt by using high shear mixer at the ratio of 2, 4, 6, and 10% by weight at Thermal Brookfield Viscometer at 135 C O and 165 C Results and Discussion O 150 -170 C for hours, then incubate at O Viscosity The viscosity of the mixtures of asphalt and RSS at the ratio of 2, 4, 6, and 10% by weight by Thermal 120 C for day Properties of asphalt and asphalt mixed with rubber are tested in Penetration value, measuring from depth of standard needle of Penetrometer sank into asphalt O Brookfield Viscometer at 135 C and O O under pressed weight of 100 grams at 25 C for minutes, the higher in hardness the lower of penetration value Softening point, the critical temperature that the asphalt becomes softens which affects the asphalt surface in bleeding Penetration Index (PI), sensitivity owing to changing of temperature of asphalt, the PI value shall be specified into level; over +1 referred to low sensitivity, under –1 high sensitivity of temperature changing and in between and +1 Torsional recovery, a test to investigate the elasticity of asphalt using steel cylinder placed in the middle of sample in cylinder cup with a specified size, twist the axis to 180 165 C are investigated It is found that the viscosity becomes higher than that of non-modified asphalt as shown in Figure and 34 RUBBER THAI JOURNAL 1: 32-39 (2012) Journal home page: www.rubberthai.com % RSS in sphalt by weight Figure Viscosity of mixed asphalt by RSS at 135 C RSS in asphalt by weight Figure Viscosity of mixed asphalt by RSS at 165 C The viscosity of the mixtures shows the value of 1.7, 3.7, 6.6, 14.5 and 19.2 times of non-modified respectively A consideration of increasing viscosity, the ratio of 2, and % revealed lower tangent slope than that of to and 10% The sudden high viscosity shall affect asphalt mixture with aggregate as the mixer will be unable to spray the asphalt being mixed with aggregate and it may cause the mixture system clogged Penetration value In term of penetration value, the asphalt used to test is AC 60/70 Grade that its penetration value is 64 Improving asphalt property by RSS at the ratio of 2, and 4% by weight provided lower penetration value of 55, and 49 respectively revealed in Figure 3, which is shown the tendency of strength 35 RUBBER THAI JOURNAL 1: 32-39 (2012) Journal home page: www.rubberthai.com % RSS in asphalt by weight Figure Penetration Values of asphalt improved with Ribbed Smoked Sheet At 6% by weight, the penetration value shows return point to the value of 51 Increasing the ratio of RSS to and 10% by weight the penetration value is increased to 76 and 78 respectively It was shown that excess of RSS affected the dispersion of rubber in asphalt causing mixed asphalt with higher penetration value that is the asphalt would be softer temperature higher at the beginning point and then gradually reduced respectively as shown in figure The values are at 47.5 for non-modified to 50.0, 60.0, 61.0, 59.5 and 56.0 C The suitable explanation is that as RSS is a macromolecule with long chain and three-dimensional network, mixing it into asphalt composed of polar aromatic material which is hard, large molecule and dispersed in saturated paraffin materials, will cause difficulty to soften the mixture The higher softening point is practical for the tropical countries Softening point Test results on softening point showed that the ratio of 2, 4, 6, and 10% by asphalt weight caused softening % RSS in asphalt by weight Figure Softening point of asphalt improved with Ribbed Smoked Sheet 36 RUBBER THAI JOURNAL 1: 32-39 (2012) Journal home page: www.rubberthai.com positive value when increasing amount of natural rubber The advantage of higher index is that the roads have sensitivity to temperature changing and can be indicated the trend on durability of the roads Penetration Index (PI) Improvement on asphalt properties with RSS will make asphalt more strength and softer at higher temperature The penetration indexes shows sensitivity to temperature changing and figure revealed that PI value has increased to % RSS in asphalt by weigh Figure Penetration Index Value of asphalt improved with Ribbed Smoked Sheet force But excess ratio resulted that this property would descend (figure 6) because the dispersion of RSS in asphalt is not enough homogenized, make level separation and finally reduction of torsional recovery Torsional Recovery Adding RSS in asphalt at higher ratio affected gradually on Torsional Recovery since RSS which is a polymer has a characteristic of elasticity, can be deformed under force and returned to the original shape after released that % RSS in asphalt by weight Figure Torsional Recovery of asphalt improved with Ribbed Smoked Sheet 37 RUBBER THAI JOURNAL 1: 32-39 (2012) Journal home page: www.rubberthai.com case It can be explained that increasing RSS to and 10% make high viscosity mixture, so the strength of modified asphalt provides higher values of toughness and tenacity Toughness-Tenacity The ratio of 2, and 6% by weight of asphalt ameliorate Toughness -Tenacity of mixed asphalt but the ratio of and 10% values are increased very rapidly shown in figures and In this % RSS in asphalt by weight Figure Toughness of asphalt improved with Ribbed Smoked Sheet % RSS in asphalt by weight Figure Tenacity of asphalt improved with Ribbed Smoked Sheet 38 RUBBER THAI JOURNAL 1: 32-39 (2012) Journal home page: www.rubberthai.com Shelburne, T.E., and Sheppe, R.L Field Experiments with Powdered Rubber in Bituminous Road Construction Rubber Age Vol.66(5) p 531-538 Conclusion The most effective ratio of Ribbed Smoked Sheet (RSS) to improve properties of asphalt is 6% by weight of natural rubber in asphalt The results from experiments show low penetration, high softening point, high penetration index, high torsional recovery, and high toughness – tenacity These properties can indicate that the roads paving with NR-modified asphalt shall have more strength and durability than using nonmodified asphalt Addition of polymer causes increasing viscosity but it will not affect mixing process However, this process needs high efficiency mixer that can be further applied to pilot scale References Fernando, M.J.,and Nadarajah, M 1992 Use of Natural Rubber Latex in Road Construction Polymer Modified Asphalt Binders ASTM STP 1108, Kenneth R Wardlaw and Scott Shuler, Eds., American Society for Testing and Material, Philadelphia Nair, NR., Mathew,N.M.,Thomas,S., Chatterjee, P and Siddqui, M.A 1992 Physical and Rheological Characteristics of Liquid Natural Rubber Modified Bitumen Polymer Modified Asphalt Binders ASTM STP 1108, Kenneth R Wardlaw and Scott Shuler, Eds., American Society for Testing and Material, Philadelphia 39 ... concentration extracted with ammonium acitate 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. .. plantations in the northeastern region will be an important area for rubber and carbon production, similar to the level of the southern region Carbon Stocks in Para Rubber Plantations and Natural Forest... increasing viscosity and elasticity diminution of temperature susceptibility higher softening point and aging resistance ameliorate of cohesion O temperature of 300 - 325 C and stirring continuously