International Journal of Applied Environmental Sciences ISSN 0973-6077 Volume 12, Number 7 (2017), pp. 1249-1260 © Research India Publications http://www.ripublication.com

Carbon Stock in Upland Agroforestry System, Province, Thailand

Chattanong Podong and Sudarat Permpoola a Department of Environmental Science, Faculty of Science and Technology, Uttaradit Rajabhat University, , Thailand 5300

Abstract The study site is located in northern of Thailand with an annual rainfall from 5-260 mm. mean rainfall 1,371 mm. / year. The soils, categorized as Clayey soils series group and Utt soils series (FAO classification), on five dominate species systems in farmers’ fields upland agroforestry regions are mainly located in lower northern, Thailand, where the main vegetations are known as (Durio zibethinus L.), mangosteen (Garcinia mangostana), lansium (Lansium domesticum Serr.), longkong (Lansium domesticum Corr.) and mixed deciduous forest. Carbon stock in the biomass was estimated by allometric equations and soil carbon stock was determined at three depths surface soil (0-10 cm), crop root zone (10-40 cm) and tree root zone (40-100). Biomass carbon stock ranged from 440 to700,360 kgC ha-1, and total carbon stock (biomass carbon and soil carbon, 0-100 cm depth) from 8,458.60 to 701,131.30 kgC ha-1, indicating that a major portion of the total amount of carbon in the system is stored in the soil. Traditional parkland agroforestry systems had relatively larger carbon stock than the improved systems, but they seemed to have only limited potential for sequestering additional carbon. On the other hand, the improved systems showed higher potential for sequestering carbon from the atmosphere. The results show that soil carbon is a substantial component of the total carbon stock of the system, suggesting the importance of considering soil carbon in carbon sequestration calculations, which at present is not recognized by Kyoto Protocol. Overall, agroforestry systems have a positive potential to sequester carbon in both aboveground and belowground. Although the carbon sequestration amount is not as

Corresponding author, Ph.D., E-mail: [email protected] a B.Sc., E-mail: [email protected]

1250 Chattanong Podong and Sudarat Permpoola large as other sequestration amount is not as large as other sequestration project such as mono-species plantation agroforestry can also provide various other land uses and environmental. Keywords: Carbon stock, Soil organic carbon, Vegetation carbon, Upland agroforestry

1. INTRODUCTION The demand to improve food security and fiber production through agriculture has increased the exploitation of natural resources by humans. Many of these resources are close to their limits support. The land resource base in all agro-ecosystem is at a very advanced level of degradation in many regions of the world (Al-Kaisi et.al., 2005). In upland agroforestry Uttaradit province, , Where the ecosystem is highly slope. In these regions, factors such as high fertility, high organic matter decomposition rate, high soil erosion. In Thailand, upland agroforestry regions are mainly located in lower northern, Thailand, where the main vegetation are known as durian (Durio zibethinus L.), mangosteen (Garcinia mangostana) and lansium (Lansium domesticum Serr.), longkong (Lansium domesticum Corr.), and mixed deciduous forest. Thus, it is all consequential to propose agricultural methods and patterns that value the environmental potentialities in the slope agroforestry areas. In this context upland agroforestry, which are circumscribed as land use systems in which woody plants are engendered in association with agricultural crops, grazing land or livestock (Breman and Kessler., 1997) have been widely advertised as a sustainable food engenderment system, and would be particularly captivating for developing regions, where the role of external inputs is not feasible (FAO, 1997). In such a setting, correct soil organic matter (SOM) management is critical to preserve the economic and environmental prospects of food engenderment, particularly in in lower northern, Thailand zones. Some surveys have shown that agro-ecological practices, like agroforestry, are consequential to amend the quality and the amount of ground organic matter. Furthermore, in upland agroforestry may be a paramount denotes to increment soil organic matter inputs and the organic carbon contents of different soil organic matter components (active, slow, and passive), which will more preponderant the tone of the soils of these areas. Referable to the intricacy of the biological, chemical and physical soil processes and their interactions, the decay of soil organic matter components is prodigiously variable. Thus, it is of interest to examine the kinetics of ground organic matter through its sundry pools, which differ in their residence time, soil mapping and control factors (Greenland et al., 1992). Looking at these aspects, this work was transmitted out in order to examine the hypothesis that agroforestry systems can Carbon Stock in Upland Agroforestry System, Uttaradit Province, Thailand 1251 promote increases in the soil organic carbon pools, contributing positively to soil quality and to the execution of more sustainable farming systems. Thus, the objective of this work was to evaluate the impact upland agroforestry and a conventional farming system on the soil organic carbon storage and pools.

2. MATERIALS AND METHODS 2.1 Site location and climate The study was undertaken in farmers’ fields in Lab-Lare district, Uttaradit province, Thailand. Uttaradit province has a tropical savanna climate (Köppen climate classification Aw). Winters are dry and very warm. Temperatures rise until April, which is very hot with an average daily maximum of 38.2 °C. The monsoon season runs from May through October, with heavy rain and somewhat cooler temperatures during the day, although nights remain warm. The study site is located in northern of Thailand with an annual rainfall from 5-260 mm. mean rainfall 1,371 mm./ year. The soils, categorized as clayey soils series group and Utt soils series (Kamo et al., 2002). Agriculture is durian (Durio zibethinus L.) is main crop, mangosteen (Garcinia mangostana), longkong (Lansium domesticum Corr.), Langsat (Lansium parasiticum), Mangosteen (Garcinia mangostana Linn.) and mixed deciduous forest. Five study plots site were selected for the study by random from elevation range 100- 300 m (Table 1).

Table 1 Characteristics of five plots study site in Lab-Lare district, Uttaradit province, Thailand Study Position Elevation(m) Size of plot (ha) sites 1 N. 17.72567, E. 99.98143 78 0.25 2 N. 17.72565, E. 99.98176 128 0.25 3 N. 17.72548, E. 99.98205 206 0.25 4 N. 17.72535, E. 99.98236 275 0.25 5 N. 17.72567, E. 99.98300 306 0.25

2.2 Biomass carbon estimation Data collection was conducted from July to September 2013. Data recorded for aboveground biomass were: (1) species and number of trees in each plot, (2) diameter at breast height (DBH), (3) tree height, (4) crown size for bushes in abandoned land. Ages of upland agroforestry system were difficult to estimate. According to owners of 1252 Chattanong Podong and Sudarat Permpoola plots, all upland agroforestry system plots were at least 15 years old. Species-specific allometric equations, through ideal for biomass estimations, were not available for all tree species in the study site. Therefore, the following general equations from (Lal, 2001), recommended by the (Nair and Nair, 2003), were used for parkland trees. Biomass of the five plot sites were estimated by general equation for < 900 mm annual rainfall from the UNFCCC guideline. (-0.535+log (¶ x DBH(cm)2) 2 Tree biomass (kg) = 10 10 ) (R = 0.94) (1) To calculate C in the biomass, C in the biomass, C fraction rate of 0.5 is suggested in the UNFCCC guideline. Below ground biomass was estimated by using the suggested root/shoot ratios, which are 0.25 for trees and 0.5 for abandoned land bushes.

2.3 Soil sampling and analysis Soil samples were collected from three depth in each plot sites: 0-10 cm (surface soil), 10-40 cm (crop root zone) and 40-100 cm (tree root zone). This was based on the expectation that the amount of C will be different by depth class depending on the presence or absence of tree roots and tillage. The amount of soil carbon stock was estimated by using the following equation bellow: Soil C stock (kg ha-1) = (% soil carbon /100) x soil mass (kg ha-1) (2) Where Soil mass (kg ha-1) = depth (m) x bulk density (mg soil m-3) x 10,000 m2 ha-1 x 1000 kg Mg-1 Bulk density was determined separately for each depth class using a 100 cm3 stainless steel cylinder. Soil organic carbon was determined by Walkley and Black’s rapid titration method [8].

3. RESULTS 3.1 Biomass carbon stock The five plot sizes upland agroforestry system was similar in tree density and extent of the dominance of major tree species (Table 2).

Carbon Stock in Upland Agroforestry System, Uttaradit Province, Thailand 1253

Table 2 Aboveground biomass, belowground biomass and biomass carbon stock in upland agroforestry system.

Study Number Dominant species Aboveground Belowground Biomass site of tree per biomass biomass carbon site (t ha-1) (t ha-1) stock (kgC ha-1)

1 25 Lansium parasiticum 1,120.57 280.14 700,360

2 8 Durio zibethinus L.(1) 70.80 17.70 440

3 12 Durio zibethinus L.(2) 209.75 55.44 131,090

4 15 Garcinia mangostana 12.39 3.10 7,740 Linn.

5 12 Lansium domesticum 18.60 4.65 11,630 Corr.

Total 851,260

Total aboveground carbon in upland agroforestry system was 851,260 kgC ha-1. The results shown aboveground biomass from Lansium parasiticum dominant species plot site (1,120.57 t ha-1), Durio zibethinus dominant species plot site (280.55 t ha-1), Lansium domesticum dominant species plot site (18.60 t ha-1) and Garcinia mangostana dominant species plot site (12.36 t ha-1), respectively. The results shown belowground biomass from Lansium parasiticum dominant species plot site (280.14 t ha-1), Durio zibethinus dominant species plot site (73.14 t ha-1), Lansium domesticum dominant species plot site (4.63 t ha-1) and Garcinia mangostana dominant species plot site (3.10 t ha-1), respectively. The results shown biomass carbon from Lansium parasiticum dominant species plot site (700,360 kgC ha-1), Durio zibethinus dominant species plot site 2 (131,090 kgC ha-1), Lansium domesticum dominant species plot site (11,630 kgC ha-1) and Garcinia mangostana dominant species plot site (7,740 kgC ha- 1), respectively.

3.2 Soil carbon stock Carbon in soil was collected in each plot of upland agroforestry system at fifteen pits (three pits per plot) at depths three of 0-10, 10-40 and 40-100 cm, respectively.

1254 Chattanong Podong and Sudarat Permpoola

Table 3. Percentage of soil organic carbon in upland agroforestry system

Study Dominant Soil organic carbon Soil organic carbon Soil organic carbon site species (%) (%) 10-40 cm (%) 40-100 cm 0-10 cm Lower Middle Uppe Lower Middle Uppe Lower Middl Uppe r r e r 1 Lansium 4.34 4.64 4.43 5.15 4.36 4.68 5.02 6.28 5.08 parasiticum 2 Durio zibet 4.06 4.97 4.45 4.34 5.03 5.35 3.91 4.56 5.34 hinus L.(1) 3 Durio zibet 4.48 4.03 4.03 5.27 4.45 4.70 5.32 4.62 4.76 hinus L.(2) 4 Garcinia m 4.58 3.42 4.95 4.95 4.36 4.82 5.27 4.49 4.97 angostana Linn. 5 Lansium d 3.69 4.41 4.10 8.85 8.98 8.29 9.74 9.18 9.20 omesticum Corr.

Percentage of soil organic carbon in upland agroforestry system range was surface soil (3.42-4.97 %), crop root zone (4.34-8.98 %) and tree root zone (3.91-9.74 %), respectively (Table 3).The percentage of soil organic carbon average in surface soil were Durio zibethinus dominant species plot 1 (4.49%), Lansium parasiticum dominant species plot (4.47%), Garcinia mangostana dominant species plot (4.32%), Lansium domesticum dominant species plot (4.07%) and Durio zibethinus dominant species plot 2 (4.18%), respectively. The percentage of soil organic carbon average in crop root zone were Lansium domesticum dominant species plot (8.71%), Durio zibethinus dominant species plot 1 (4.91%), Durio zibethinus dominant species plot 2 (4.81%), Lansium parasiticum dominant species plot (4.73%) and Garcinia mangostana dominant species plot (4.71%) respectively. The percentage of soil organic carbon average in tree root zone were Lansium domesticum dominant species plot (9.37%), Lansium parasiticum dominant species plot (5.46%), Garcinia mangostana dominant species plot (4.91%), Durio zibethinus dominant species plot 2 (4.92%) and Durio zibethinus dominant species plot 1 (4.60%), respectively (Fig 1). Carbon Stock in Upland Agroforestry System, Uttaradit Province, Thailand 1255

12.00 10.00 surface soil crop root zone tree root zone 8.00 6.00 4.00 2.00 0.00

Soil organic organic Soil (%) carbon Lansium Durio zibethinusDurio zibethinus Garcinia Lansium parasiticum L. 1 L. 2 mangostana domesticum Dominant species site Linn. Corr.

Fig.1 Percentage of soil organic carbon in surface soil (0-10 cm), crop root zone (10- 40 cm) and tree root zone (40-100 cm) of upland agroforestry system

Soil carbon stock carbon in upand agroforestry system were total 4,208.80 kg ha-1 and 322.90 kg ha-1 in surface soil, 1,253.70 kg ha-1 in crop root zone and 2,632.20 kg ha-1, respectively. The total soil carbon stock were Lansium domesticum Corr. dominant species site (1,296.40 kg ha-1), Lansium parasiticum dominant species site (771.20 kg ha-1), Durio zibethinus L. dominant species site 2 (720 kg ha-1), Garcinia mangostana Linn dominant species site (718.60 kg ha-1) and Durio zibethinus L. dominant species site 1(702.50 kg ha-1), respectively (Table 4). Table 4 Soil carbon stock carbon in upland agroforestry system Stu Dominant Soil carbon stock (kg ha-1) Total -1 dy species Surface soil Crop root zone Tree root zone (kg ha ) site (0-10cm) (10-40 cm) (40-100 cm)

1 Lansium p 67.05 212.85 491.40 771.30 arasiticum 2 Durio zibet 67.40 220.80 414.30 702.50 hinus L.(1) 3 Durio zibet 62.70 216.30 441.00 720.00 hinus L.(2) 4 Garcinia m 64.75 211.95 441.90 718.60 angostana Linn. 5 Lansium d 61.00 391.80 843.60 1,296.40 omesticum Corr. Total (kg ha-1) 322.90 1,253.70 2,632.20 4,208.80 1256 Chattanong Podong and Sudarat Permpoola

3.3 Total carbon (biomass + soil) stock Total carbon stock (biomass+soil) of each system was calculated and compared in five different dominant species type. The toal carbon stock in upland agroforestry system was 855,468.80 kg C ha-1. The total carbon stock following dominant species site were Lansium parasiticum dominant species site (701,131.30 kg C ha-1), Durio zibethinus L. dominant species site 2 (131,810 kg C ha-1), Lansium domesticum Corr. dominant species site (12,926.40 kg C ha-1), Garcinia mangostana Linn. dominant species site (8,458.60 kg C ha-1) and Durio zibethinus L. dominant species site 1 (1,142.50 kg C ha-1), respectively (Table5).

Table 5. Total carbon stock carbon in upland agroforestry system Study site Dominant spec Biomass carbo Soil carbon st Total carbon ies n stock ock stock (kg C ha-1) (kg ha-1) (kg ha-1) 1 Lansium parasi 700,360 771.30 701,131.30 ticum 2 Durio zibethinu 440 702.50 1,142.50 s L.(1) 3 Durio zibethinu 131,090 720.00 131,810 s L.(2) 4 Garcinia mang 7,740 718.60 8,458.60 ostana Linn. 5 Lansium domes 11,630 1,296.40 12,926.40 ticum Corr. Total (kg ha-1) 588,085854

3. DISCUSSION 3.1 Biomass carbon stock In term of biomass carbon stock, upland agroforestry system, especially Lansium parasiticum dominant species site, stored more carbon than other agroforestry systems demonstrated relatively low carbon storage within the range for forest plantation in Thailand. Generally, species selected in plantation was inhibited by intense competition associated with vigorous growth of tree species in nature forest (Pibumrung et.al., 2008). Obviously, the agroforestry system are relatively young, but they are not likely to store as much carbon as the parkland at the end of their assumed rotation period (25 years) because branch of trees are annually pruned similarly and planted in a high density such that tree biomass accumulation per tree will be Carbon Stock in Upland Agroforestry System, Uttaradit Province, Thailand 1257 comparatively. However, having a large carbon sequestration potential. Carbon stock refers to the absolute quantity of carbon held at the time of inventory, whereas, as stated before, carbon stock relate to the process of removing carbon from the atmosphere and deposition in a reservoir. Some study plantation in Thailand that para rubber plantation was 24,828.87 kgC ha-1 and total abovebiomass carbon (24,828.87 kgC ha-1) and belowground (6,082.37 kgC ha-1) (Podong, 2016).

3.2 Soil carbon stock Determination of the baseline for soil carbon is a major issue while assessing and comparing the carbon stock potential of land use systems, if soil carbon is taken into account in such calculations, which at present is not according to the Kyoto Protocol. Soil sampling depth is a significant factor in estimating the amount of carbon stored, as well as the potential for carbon stock. Soil carbon in agroforestry relation with organic matter and varies by other factors such as: decomposition from microbial activity (Pretty and Ball, 2001), soil tillage (Roshetk et al., 2002), cropping system (Salila et al., 2001), and soil temperature and soil respiration (Smith and Fend, 2010). The amount of SOC is balanced by the input and outputs. The input is usually in the form of litterfall (UNFCCC, 2006). Summarized leaf and total fine litterfall data for twenty sites in the humid forest zone. Some study in Thailand reported that land use in the mixed deciduous forest, reforestation and agriculture land at Nam Yao sub- watershed soil carbon was 35,762, 19,525 and 10,310 kgC ha-1 respectively (Pibumrung et.al., 2008).

3.3 Total carbon stock The objective of this study was to compare carbon stock of the five dominant species with upland agroforestry system and discuss their carbon sequestration potential. Carbon sequestration potential is usually calculated based on hypothetical baseline, and it is customary to consider the difference in carbon content in the system “before” and “after” the project as the carbon sequestration potential and express it by time averaged quantities (Mg C/ year) (Zhang and Zhang, 2003; Zhang et al., 2007). Agricultural systems contribute to carbon emissions through several mechanisms: (1) the direct use of fossil fuels in farm operations; (2) the indirect use of embodied energy in inputs that are energy-intensive to manufacture (particularly fertilizers); and (3) the cultivation of soils resulting in the loss of soil organic matter. On the other hand, agriculture is also an accumulator of carbon, offsetting losses when organic matter has accumulated in the soil, or when aboveground woody biomass acts either as a permanent sink or is used as an energy source that substitute for fossil fuels (Zhang et al., 2007). 1258 Chattanong Podong and Sudarat Permpoola

4. CONCLUSIONS The five dominant species site of upland agroforestry system, especially Lansium parasiticum site store significant amounts of carbon in their biomass. However, not likely to be considered for carbon sequestration projects anytime soon because Kyoto Protocol currently admits only carbon sequestration as a result of implemented mitigation projects. On the other hand, the biomass stored in the newly introduced agroforestry system can be counted as carbon stock for carbon trading calculations. However, the absolute amounts of carbon stored in these systems per unit area would not be as large as for agroforestry, because of the nature of planting configurations and tree management requirements in such system. Overall, agroforestry systems have a positive potential to sequester carbon in both aboveround and belowground. Although the carbon sequestration amount is not as large as other sequestration amount is not as large as other sequestration project such as mono-species plantation agroforestry can also provide various other land uses and environmental.

ACKNOWLEDGMENTS This study was funded by Uttaradit Rajabhat University and private owner for study site with upland agroforestry system, Lab-Lare district, Uttaradit province, Thailand.

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