Scholarly article on topic 'Carbon Release from Agricultural Cultivated Peats at Sungai Hitam Wetland, Bengkulu Province, Indonesia'

Carbon Release from Agricultural Cultivated Peats at Sungai Hitam Wetland, Bengkulu Province, Indonesia Academic research paper on "Agriculture, forestry, and fisheries"

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Abstract of research paper on Agriculture, forestry, and fisheries, author of scientific article — Muhammad Faiz Barchia

Abstract This research aimed to determine CO2 emission related to agricultural activities in peat soils. The research was conducted in peak of drought season, August, 2015 at Sungai Hitam, Bengkulu, Indonesia. In order to get representative sampling sites, field survey was conducted in May, 2015 in the research location. Primary data was collected from rice field, vegetables, bare land, and oil palm involved incubated CO2 emissions, peat thickness, and level of water tables. The data were analyzed statistically from 10selected samples of the rice fields, 7 selected samples of lowland vegetables fields, 3 selected samples of bare lands, and 8 selected samples of oil palm fields. CO2 emission values under the land on Sungai Hitampeat were as follow; 237.86, 238.57, 259.35, and 265.35 mg m-2 hr-1, respectively. Moreover, carbon releases based on peat thickness; <100, 101 – 150, 151 – 200, 201 – 250, and > 250 cm, respectively were 119.71, 189.35, 229.47, 288.58, and 297.59 mg m-2 hr-1. The trend of CO2 emission (y1) related to peat thickness (x1) fit with a following equation; y1 = 3.996x1 0.778; R2 = 0.953. Level of carbon emission affected by water tables; <100, 101 – 150, 151 – 200, and >200 cm, respectively was 192.80, 245.54, 292.21, and 309.97 mg m-2 hr-1. CO2 emission rate (y2) related to lowering water tables (x2) conformed to a following formula; y2 = 23.96x2 0.48; R2 = 0.949. Peat ecosystems sequestering carbonhave undegone for thousands of years. Therefore, cultivated peat for sustainable agriculture development should consider in managing peat thickness and water table.

Academic research paper on topic "Carbon Release from Agricultural Cultivated Peats at Sungai Hitam Wetland, Bengkulu Province, Indonesia"

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Agriculture and Agricultural Science Procedia 11 (2016) 71 - 76

International Conference on Inventions & Innovations for Sustainable Agriculture 2016, ICIISA

Carbon Release from Agricultural Cultivated Peats at Sungai Hitam Wetland, Bengkulu Province, Indonesia

Muhammad Faiz Barchia*

Faculty of Agriculture, University of Bengkulu, Bengkulu 38371, Indonesia

Abstract

This research aimed to determine CO2 emission related to agricultural activities in peat soils. The research was conducted in peak of drought season, August, 2015 at Sungai Hitam, Bengkulu, Indonesia. In order to get representative sampling sites, field survey was conducted in May, 2015 in the research location. Primary data was collected from rice field, vegetables, bare land, and oil palm involved incubated CO2 emissions, peat thickness, and level of water tables. The data were analyzed statistically from 10selected samples of the rice fields, 7 selected samples of lowland vegetables fields, 3 selected samples of bare lands, and 8 selected samples of oil palm fields. CO2 emission values under the land on Sungai Hitam peat were as follow; 237.86, 238.57, 259.35, and 265.35 mg m-2 hr-1, respectively. Moreover, carbon releases based on peat thickness; <100, 101 - 150, 151 - 200, 201 - 250, and > 250 cm, respectively were 119.71, 189.35, 229.47, 288.58, and 297.59 mg m-2 hr-1. The trend of CO2 emission (y1) related to peat thickness (X1) fit with a following equation; y1 = 3.996x1tt778; R2 = 0.953. Level of carbon emission affected by water tables; <100, 101 - 150, 151 - 200, and >200 cm, respectively was 192.80, 245.54, 292.21, and 309.97 mg m-2 hr-1. CO2 emission rate (y2) related to lowering water tables (X2) conformed to a following formula; y2 = 23.96x2048; R2 = 0.949. Peat ecosystems sequestering carbon have undegone for thousands of years. Therefore, cultivated peat for sustainable agriculture development should consider in managing peat thickness and water table.

© 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.Org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of the Faculty of Animal Sciences and Agricultural Technology, Silpakorn University

Keywords.agricultural cultivated peatlands; peat thickness; water table; CO2 emission

• Corresponding author. Tel.: 6281271954246; fax: 6273621170. E-mail addressfaiz_barchia@yahoo.com

2210-7843 © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Peer-review under responsibility of the Faculty of Animal Sciences and Agricultural Technology, Silpakorn University doi:10.1016/j.aaspro.2016.12.012

1. Introduction

Indonesian peatlands lie on geographic areas which are characteristically prone to environmental impacts (Barchia, 2006; Sabiham, 2010). During a dry season, and the El-Nino effect, prolonged drought period initiates fire on peatlands, causing a hazard to animal environment and human. Indonesia peatlands plays an important role on ecosystem sustainability (Wösten et al., 2008). Today, the peatlands are an increasingly significant land resource for livelihood and economic development. While acting as a carbon sink under the natural forest, it turns into a carbon source of greenhouse gas once the peat forest is cleared and drained (Agus et al., 2010).

Indonesian peatlands, one of important natural resources, maintain hydrological systems and other ecological functions for human life and the whole biodiversity. In utilizing peatlands to support agricultural development, the peat should be cultivated under considerable management based on planning, suitable technologies, and perfect land management (Sowondo, et al. 2010). By following considerable management steps, agricultural cultivated peatlands provide high productive sustainable agriculture and food productions (Barchia, 2006; Kyuma, et al. 1992). Information about marginally peat characteristics and fragile ecosystems should be collected for accurate planning, perfect design in peat cultivation and conservation efforts (Agus and Subiksa, 2008).

Indonesia peatlands become the fourth following Russia, Canada, and US in term of area of peatlands. Based on the size of an area, the Indonesia peats cover 27,06 millions Ha, consisting of peat soil and peaty soil (Indonesia Soil Research Center, 1981^. Ismunadji and Soepardi (1982) reported that in Sumatera Island, the peatlands may be 11 m in thickness. Driessen and Soepraptohardjo (1974) stated that peatlands with thickness of 15 m were commonly found along eastern Sumatera areas. In Sumatera and Kalimantan peatlands with thickness of 0 - 100, 100 - 200, and > 200 cm will be at the proportion of 36.2%, 14,0% and 49.8%, respectively (Radjagukguk, 1991).These peatlands are ideal source for potential agricultural cultivation. However, to develop peatlands for use in agriculture, careful consideration should be directed to productivity of the selected area, thicker of the peat, economical viability, and impact to environment, particularly the possibility of releasing CO2 gas to the atmosphere (WWF, 2008).

Carbon transformation rates are quite related to peat thickness in which the thick peat would transform more carbon comparing to moderate and thin peat. Carbon releases from peatlands occur not only because of abiotic factors but also because of anthropogenic modified resultants (Melling et al. 2013). Various human activities working on peatlands affect natural peat ecosystems which disturb ecosystems with vary effect of carbon transformation (Hooijer et al., 2010). In western Sumatera, peatlands have been changed to agricultural cultivated area. However, there is little information with respect to peat destabilization and carbon transformation. In Indonesia, C-emission as a result of peat utilization have been given little attention compared with the application and utilization of peat for commercial purpose (Sabiham, 2010). Therefore, C-emission as a result of peat destabilization for use in agriculture in Western Sumatera was studied with respect to carbon emission rate from agriculture cultivation, peat thickness, and water table management.

2. Materials and Methods

The research was conducted in the Sungai Hitam agricultural cultivated peatlands, Bengkulu, Sumatera, Indonesia. The peatland covered about 2,500 ha. The research was conducted in peak of El-Nino effect in August 2015. In order to get representative sampling sites, field survey was conducted in May, 2015 in rice fields, lowland vegetables fields, bare land, and oil palm cultivated areas. Primary data collected from the land involved incubated emission gas, peat thickness, and level of water table in the agricultural cultivated areas. Carbon emission was analyzed at Soil Science Laboratory, Faculty of Agriculture, University of Bengkulu. The gas emitted through the peat surface was trapped by closed chambers made of transparent mica (Aini et al., 2007). Rate of carbon emission characteristic from incubated peat in the field trapped by KOH 0.2 N solution, then the carbon emission in the form of CO2 measured through titration method. Chemical solution indicator used for analisys of the CO2 emission was metyl orange of phenolphatalein, and then titrated by solution of HCl 0.1 N (Widyastuti and Anas, 2013). In oder to find equation formulas between CO2 emissions and peat thickness, and between the CO2 emissions and water tables, samples of CO2emissions, peat thickness, and level of water tables were analyzed statistically from 10 selected samples of the

rice fields, seven selected samples of lowland vegetables fields, three selected samples of bare lands and eight selected samples of oil palm fields.

3. Results and Discussions

3.1. CO2 Emission from Different Land Use

Agricultural cultivated peats with various plants managements on peatlands influenced the rate of carbon release. Level of carbon emission from land of rice, vegetables, bare land, and oil palm was 237.86, 238.57, 259.35, and 265.35 mg m-2 hr-1 respectively. These carbon emissions were lower than previous research in Central Kalimantan in which CO emissions were range of 350 - 670 mg CO2 m-2 hr-1(Rumbang et al., 2009). The CO2 emission on Sungai Hitam peat Bengkulu with various plant cultivation is shown (Figure 1).

300.00

g 250.00

g 200.00 eg

JÜ 150.00

J 100.00

Rice Vegetables Bare Lands Oil Palm

Figure 1. CO2 Emission from Agricultural Cultivated Peatlands.

CO2 emission with oil palm plantation and bare land was slightly higher than those of rice and vegetable cultivation although there was no statistically significant difference among these crops. On agricultural peatland in West Kalimantan, CO2 emission from oil palm plantation (perennial crops) was higher than these from corn and vegetables (annual crops) (Rumbang, et al, 2009). CO2 release under dry season condition in Sungai Hitam peat was two times higher than that in Central Kalimantan which CO2 emission under drainage (-25 cm water level) of rice plant was reported to be in the range of 111.41 - 161.18 mg m-2 hr1 (Barchia and Sabiham, 2002).

3.2. CO2 Emission from Different Peat Thickness

Using peatlands for agricultural purposes should understand the inherent characteristics of the peatlands, particularly the thickness of peat. Rate of peat decomposition correlated with thickness of peat in the Sungai Hitam. Average carbon emission in the form of CO2 of Sungai Hitam peatland Bengkulu in the dry season with various peat thicknesses is shown (Table 1).

Table 1. Rate of CO2 emission under various peat thickness on Sungai Hitam Bengkulu.

Peat Thickness CO2 Emission

(cm) (mg m-2 hr-1)

<100 119.71

101 - 150 189.35

151 - 200 229.47

201 - 250 288.58

>250 297.59

Analytical regression between peat thickness and carbon release in form of CO2 on Sungai Hitam cultivated peat is shown (Figure 2).

350.00 ^ 300.00

250.00

200.00 -■§ 150.00

W 100.00

O 50.00

■ Over-all land uses

- y = 3.9 9 6 3 x07784

R2 = 0.9534 A Oil Palm

- y = 10.926x05905

R2 = 0.9459 Rice Field

-y = 2.88 77x08394

R2 = 0.9685

—i—

100 150 200

Peat Depths (cm)

Figure 2. Correlation between CO2 emission and peat thickness in agricultural cultivated peatlands.

Rate of carbon transformation usually correlated with the thickness of peat, with the carbon release on thick peat higher than that of moderate and thin peat. The correlation between CO2 emission rate (yi) and peat thickness(xi) in Sungai Hitam Bengkulu can be presented in the following equation:

yi = 3.996xi0778 R2 = 0.953 Peat thickness contributed to value of carbon resources and these played as important characteristics carbon release in agricultural peatlands (Salampak et al., 2014). Peat thickness was a main factor that should consider in peat cultivation for agriculture in which the thicker peat is, the more carbon release would occur from the cultivated land (Handayani, 2009). With the occurrence of an acceleration of decomposition in thick peat, the area with thick peat used for agriculture should be managed carefully, and land productivity should be maintained by understanding peat inherent characteristics (Widjaja Adhi, 1997).

3.3. CO2 Emission from Different Water Table

Soil oxidative and reductive conditions are regulated by level of water table. Therefore, water level management could maintain CO2 emission from peatlands. Main constraint in developing peatlands for agriculture use was about the implementation of suitable drainage infrastructures. Changes in land use and plant management would affect the level of needed water table. The average of CO2 emission and the level of water table in Sungai Hitam peat, Bengkulu were shown Table 2.

Table 2. Rate of CO2 emission under different level of water table in Sungai Hitam, Bengkulu.

Water Table CO2 Emission

(cm) (mg m-2 hr-1)

<100 192.80

101 - 150 245.54

151 - 200 292.21

>200 309.97

The emission of CO2from Sungai Hitam peat, Bengkulu in dry season was significantly high (Table 2). Carbon emission from Sungai Hitam peat, Bengkulu was two times higher than those of other studies (Barchia and Sabiham, 2002). The depth of water table in Sungai Hitam peat contributed progressively to the increase of carbon release from the peat in this location. Rate of CO2 transformation from Sungai Hitam agricultural cultivated peat is shown (Figure

■ Over-all land uses

-y = 23.968x048

R2 = 0.9497 Oil Palm

-y = 33.477x04132

R2 = 0.9496

♦ Rice

-y = 17.572x05386

R2 = 0.9713

Figure 3. Relation between CO2 emission and water table in agricultural cultivated peatlands.

Rate of CO2 emission (y2) in correlation to the level of water tables (x2) in Sungai Hitam agricultural land was formulated in the following equation:

y2 = 23.96X2048, R2 = 0.949

Accelerated CO2 emission was contributed to the shallow level of water table in Sungai Hitam. There was linear correlation between level of water depth and CO2 emission values in agricultural peatland in Central Kalimantan (Rumbang, et al. 2009). CO2 emission from drainaged peat increase following depth of water level (Nusantara et al., 2014).Therefore, to maintain sustainable agriculture productivity, the level of water table should be maintained at the depth of root zone. Land and plant management, peat thickness, peat moisture and aeration, and depth of water tables were contributed to the values of carbon peat transformation (Barchia, 2006). Level of water table for sustainable rice productivity should be maintained at the level of +5 to +10 cm. The depth of water table should be controlled in the level of -25 cm when cultivating vegetables. Level of water table for the perennial crops, oil palm plantation should be maintained in the range of -50 to -60 cm to avoid the degradation of agricultural peat soils.

4. Conclusions

The emission of CO2 in Sungai Hitam peat, Bengkulu from oil palm plantation and bare land was slightly higher than that of rice field and vegetables cultivation. However, there was not statistical significant difference with respect to the release of CO2 among all crops. Agricultural peat cultivation in thick peat and deeper water table contributed to the increase of CO2 emission in Sungai Hitam peat, Bengkulu. Use peatland for agricultural development should take peat thickness and level of water table into consideration to maintain the productivity of sustainable agriculture.

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350.00

1 300.00

^ 250.00 -\

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■§ 150.00

w 100.00

O 50.00

—I-1-1-1-1

50 100 150 200 250

Water Table (cm)

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