Inventory of pollutions from rice field residue open burning based on field survey

Transcription

1 2011 2nd International Conference on Environmental Science and Technology IPCBEE vol.6 (2011) (2011) IACSIT Press, Singapore Inventory of pollutions from rice field residue open burning based on field survey Penwadee Cheewaphongphan and Savitri Garivait The Joint Graduate School of Energy and Environment King Mongkut s University of Technology Thonburi, Center for Technology and Environment, Ministry of Education, Bangkok, Thailand penvadee_chee@hotmail.com Adisak Pongpullponsak Department of Mathematics, Faculty of Science, King Mongkut s University of Technology Thonburi, Bangkok 10140, Thailand Abstract Open Burning of rice residue is the common practice in Thailand that releases pollutants and green house gases emission. This study intended to estimate the spatial and temporal distribution of emissions from rice field residues burning during in Thailand, using questionnaire survey and field experiment. Based on the harvested area from published by Office of Agricultural Economics (OAE), the questionnaire survey, and the field experiment, the annual average amount of burned area was estimated as 4.7 Mha (SD 0.2 Mha), included 2.1 Mha (SD 0.2 Mha) in irrigated-area and 2.5 Mha (SD 0.06 Mha) in rain-fed area. The average annual amount of burned rice residue is about 21.7 Mt (SD 1.8 Mt). About 62 percent of overall burned residue was the major rice residue and 38 percent was the minor rice residue. In case of burning of major rice residue, it was mainly burned during October to December for preparing minor rice plantation and during March to May for preparing major rice plantation for the following year. In minor rice residue, it was mainly burned during February to April for preparing the next crop. Based on 2006 IPCC Guideline, by using emission factor from previous study and annual amount of burned rice residue, the annual average amount of GHG emissions was about 27 Mt CO 2eq (SD 2.3 Mt CO 2eq ) which included 17 Mt CO 2eq (SD 0.3 Mt CO 2eq ) from burning of major rice residue and 10 MtCO 2eq (SD 2.2 Mt CO 2eq ) from burning of minor rice residue. From the overall result, it demonstrated, in Thailand the burning of rice residue was mainly occurred with the major rice residue especially in the rain-fed area, during March to May which emits GHG emission 40 percent of annual amount of GHG emissions from burning of rice residue. Keywords-rice residue; open burning; Greenhouse gases; emissions I. INTRODUCTION Thailand is an agricultural country and the main economic crop is rice. In 2009, value of rice export was about 172,208 million baht which was about 31 percentage of value of agricultural export [1]. In Thailand, rice is classified by season into two types. The first type is major rice which planted in the rainy season (start between May and October and finish between August and April of the follow year). The second type is minor rice which planted in the dry season (start between November and April of the next year and finish between February and October). Rice Stubble and straw are the agricultural residues generated after harvesting process. From the harvesting season of major rice and minor rice demonstrates stubble and straw are occurred all year. There are 3 management methods as open burning, soil incorporation, and commercial utilization [2]. In Thailand, the burning of rice residues is the common eliminated method [3, 4] and occurred annually [4, 5] because of saving time and cost [2, 6-7]. Pollution Control Department reports the paddy field is burned about 50 percentages and 75 percentages for major rice and minor rice respectively [8]. The rice residue open burning contributes the greenhouse gases emission as carbon dioxide (CO 2 ), carbon monoxide (CO), methane (CH 4 ), nitrous oxide (N 2 O), and nitrogen oxide (NO x ) and particulate matter as PM 2.5 due to the incomplete combustion process [9] and also causes of the losses of nutrients and organic matter [2, 10-11]. Based on Guideline IPCC 2006, the amount of GHG emission from agricultural residue open burning can be calculated using equation (1); L A M C G 10 3 (1) fire = B f ef Where L fire (tons of each emission) is the amount of emissions from burning, A (ha) is the amount of harvested area, M B (g kg -1 d.m. burned) is mass of fuel available for combustion, C f (dimensionless) is the combustion factor, and G ef (g kg -1 d.m. burned) is emission factor [IPCC 2006]. From the equation, the result of the production between harvested area (A), mass of fuel available for combustion (M B ) and combustion factor (C f ) is the amount of residue burned. So, the principle of the estimation of emission from agricultural residue open burning is the production between amount of residue burned and emission factor of a particular emission. This study attends to estimate the spatial and temporal distribution of the emission from the rice field residue open burning in each crop season between 1998 and 2009, using 2006 IPCC Guidelines method. The seasonal amount of rice residue burned comparing between irrigated area and rainfed area through the questionnaire survey and field experiment. The emission factor obtained from literature review. II. METHODOLOGY Based on principal of Guideline IPCC 2006, emission equation used to estimate the amount of emission from rice residues open burning in this study is V2-93

2 L G A A M C 10 3 (2) fire = ef B B f Where L fire (tons of each emission) is the amount of emissions from burning, G ef (g kg -1 d.m. burned) is emission factor, A (ha) is the amount of harvested area, A B (percentage) percentage of burned area, M B (g kg -1 d.m. burned) is mass of fuel available for burning, C f (dimensionless) is the combustion factor. The EF of CO 2, CO, CH 4, N 2 O, NO x, and PM 2.5 mostly specific for rice straw open burning are obtained from literature review and presented in the table 1. The value of harvested area (A) is published annually by Office of Agricultural Economics (OAE). The value of percentage of area burned, mass of fuel available for burning and combustion factor are estimated from the questionnaire survey and the field experiment. A. 2.1 Questionnaire survey The questionnaire survey is conducted with the objective to investigate the percentage of area burned, the mass of fuel available for burning and the combustion factor. Survey question related to this study is shown in table farmers were interviewed during 2007 to The number of questionnaire survey calculated based on rank set sampling method, at 5% proportional error and 95% confident level. The distribution of the site survey obtained from the interpretation of fire hot spot (FHS) detected by Moderateresolution imaging spectroradiometer (MODIS) sensor aboard the Terra and Aqua satellites and land use map. The site survey included 5 provinces in the Northern; Nakornsawan, Petchchabun, Pitchsanulok, Lampang, and Chiengmai, 6 provinces in the North-eastern; Khnongkai, Surin, Konkaen, Buriram, Mahasarakam, and Nakornratchasrima, 5 provinces in the Central; Chainat, Petchburi, Ratchaburi, Chachoengsao, and Suphanburi, and 4 provinces in the Southern; Chumporn, Nakornratchasrima, Pattalung, and Songkla (the location of questionnaire survey is shown in the fig. 1). TABLE I. DEFAULT VALUE OF EMISSION FACTOR Factor Default value EF OB of CO 2 (g CO 2 kg -1 d.m.burned) a 1,18 EF OB of CO (g CO kg -1 d.m.burned) a EF OB of CH 4(g CH 4 kg -1 d.m.burned) b 2.70 EF OB of N 2 O(g N 2 O kg -1 d.m.burned) b 0.07 EF OB of NO x (g NO x kg -1 d.m.burned) c 3.10 EF OB of PM 2.5 (g PM 2.5 kg -1 d.m.burned) a a. Kanittha Kanokkanjana and Savitri Garivait, 2010 b. Andrea, M.O., Merlet, P., 2001 c. Kiran L. Kadam, Loyd H. Forrest, and W. Alan Jacobson, 2000 TABLE II. A PART OF QUESTION IN QUESTIONNAIRE SURVEY USING IN THIS STUDY 1. What is the size of your paddy field? 2. How many times do you usually plant rice in your area per year? 3. What is your water resource? (Irrigation / Rain fed) 4. Do you burn your paddy field? If yes, how much of the area burned? 5. Do you use the rice residue for any purpose? If yes, how much does it used? 6. Do you burn the rice residue in your area? If yes, how much does it burned? 7. Which picture represents as the characteristic of your residue after burned? Figure 1. Location of questionnaire survey B. Field experiment The purpose of the field experiment is to measure the amount of rice residues per area. 30 sites on major rice field and 30 sites on minor rice field were experimented during 2007 to samples is the minimum acceptable value of statistical precision. The experiment is done by random 5 sampling plots at 4 4 m 2 (4 corners and 1 center of the paddy field), then collects the residues that cover on the soil and closes to the ground separately between stubble and straw. Then stubble and straw in the sampling plot were weight. Due to the span of pushcart is about m, size 4 4 m 2 represents the all characteristic of paddy after harvesting. 1) Experimental estimation of A B The percentage of burned area (A B ) is the proportion of paddy field burned to the overall of paddy field. This parameter obtained from questionnaire surveys. From the questionnaire survey found the fraction of burned area depends on crop season and area. The percentage of burned area was in the range of 38 to 62 for major rice season (SD ) and in the range of 28 to 72 for minor rice season (SD ). In term of area, the percentage of burned area in the irrigated area was V2-94

3 approximately 67; in the rain-fed area, it was approximately 33. From these results it demonstrates the main of burned residue is major rice residue and occurred in the irrigatedarea. The results of this study had the wider range than the value of 50% of major area and 75% of minor area reported by PCD [4] because of the varieties of site study in this study (cover the irrigated area and the rain-fed area). 2) Experimental estimation of M B The mass of fuel available for combustion (M B ) is the amount of unused rice residue in unit area. This study assesses this factor from the subtraction between the amount of rice residue in unit area and the amount of rice residue used. The amount of residue in unit area obtained from field experiment and the fraction of utilized residue got from questionnaire survey. Analytical on the amount of residue per unit area and the fraction of used residue found the amount of residue available for burning depends on type of residue and crop season. The average of stubble and straw left in the field was about 8.1 tons/ha (SD 0.13 tons/ha) and 7.6 tons/ha (SD 0.04 tons/ha) respectively. The mass of residue subjected to open burned was about 3.7 to 4.9 tons/ha, and 11.2 to 11.5 tons/ha for major rice residue (stubble/straw) and minor rice residue (stubble/straw) respectively. From these results it demonstrates the main of fuel in paddy field open burning is major rice stubble. This was more intensive than some previous study which reported between 0.82 and 6.91 tons/ha [4, 10]. 3) Experimental estimation of C f The combustion efficiency is the proportion of rice field residue consumed by fire. This factor obtained from questionnaire survey. From the questionnaire survey found the combustion efficiency depends on crop season. The combustion efficiency varied on for major rice residue (SD ) and for minor rice residue ( ). From these results it demonstrates the main of residue that burned in the field is major rice residue. The result of major rice residue was associated to the value 0.87 of combustion efficiency for all rice, reported by PCD [4] III. RESULT AND DISCUSSION A. Spatial and temporal distribution of rice residue burned in the field The annual amount of rice residue burned during is estimated through the harvested area, the percentage of area burned, mass of fuel available for burning and combustion factor. The annual amount of harvested area published by Office of Agricultural Economics (OAE) and the annual amount of burned area obtained from the field survey and the questionnaire survey are shown in table 3. By using the value of mass of fuel available for combustion (M B ), the annual amount of burned residue and the density of burned residue are shown in table 4. Result can be summarized in the following: The annual average amount of harvested area is about 10.0 Mha (SD 0.3 Mha). The annual amount of harvested area of major rice varies between 8.1 and 8.8 Mha, the annual average amount is about 8.6 Mha (Standard deviation; SD 0.18 Mha). The annual amount of harvested area of minor rice varies between 1.0 and 2.0 Mha, the annual average amount is about 1.4 Mha (SD 0.28 Mha). Main of major rice (25 percent of major rice field) is in the rain-fed area. Main of minor rice (74 percent of minor rice field) is in the irrigated-area. The annual average amount of burned area is about 4.7 Mha (SD 0.2 Mha). The annual amount of burned area of major rice varies between 3.6 and 3.9 Mha, the annual average amount is about 3.8 Mha (SD 0.08 Mha). The annual amount of burned area of minor rice varies between 0.6 and 1.3 Mha, the annual average amount is about 0.8 Mha (SD 0.2 Mha). The annual amount of burning in irrigated-area is about Mha and in rain-fed area is about Mha. The annual average amount of burned area in irrigated-area is about 2.1 Mha (SD 0.2 Mha) and in rain-fed area is about 2.5 Mha (SD 0.06 Mha). Although the burning in the rain-fed area is higher than irrigated-area, the fraction of burned area to overall area of irrigated-area is higher than rain-fed area. The burning is mainly occurred in the irrigatedarea. The average annual amount of burned rice residue is about 21.7 Mt (SD 1.8 Mt). The annual amount of burned residue varies between 12.8 and 13.8 Mt for major rice residue and between 5.6 and 12.0 Mt for minor rice residue. The annual amount of residue burned in the irrigated-area is about Mt and in the rain-fed area is about Mt. In term of burned residue to harvested area, about 2.2 tons/ha of major rice and 6.8 tons/ha of minor are burned annually. For the type of reside burned in the field, about 75 percent of major rice residue and 80 percent of minor rice residue that burned in the field is straw. TABLE. III THE ANNUAL AMOUNT OF HARVESTED AREA ABD BURNED AREA DURING 1998 TO 2009 Harvested area (Mha) Burned area (Mha) Irrigated Rain-fed Major Minor Major Minor TABLE. IV ESTIMATION OF ANNUAL AMOUNT OF BURNED RICE RESIDUE AND AMOUNT OF RESIDUE PER HARVESTED AREA UNIT DURING Burned residue (Mt) Major residue Minor residue stubble straw stubble straw Irrigated area Rain-fed area Burned residue/harvested area (t/ha) Irrigated area Rain-fed area V2-95

4 From these results, the burning of rice residue is mainly occurred with the minor rice straw especially in the irrigated-area. Fig. 2 shows the ly about of burned rice field residue between 1998 and The amount of burned rice residue is fluctuation but has the same cycle. The analytical on the fraction burned of residue in each and the amount burned residue found there are 2 peaks period of residual burning; the first period is between March and May and the second period is between October and December. In major rice residue, it is mainly burned during October to December and during March to May. The objective of the first burning is to prepare area for minor rice plantation. The objective of the second burning is to prepare area for plantation of major rice of the following crop season. In minor rice residue, it was mainly burned during February to April for preparing the next crop. B. Spatial and temporal distribution of emission from rice residue burning in the field The emission factor published in previous study (as shown in table 1) and the amount of burned residue (the result from previous topic) are combined to estimate the emission from burning of rice residue in the field. The amount of emission is tabulated as shown in table 5; result can be summarized in the following way: The annual amount of pollutant (CO, NO x, and PM 2.5 due to the burning of rice residue in the range of Mt, Mt, and Mt respectively, the average annual amount is 2.9 Mt (SD 0.2 Mt) of CO, 0.07 Mt (SD 6 Mt) of NO x and 0.6 Mt (SD 0.05 Mt) of PM 2.5. The annual amount of GHG (CO 2, CH 4, and N 2 O) due to the burning of rice residue in the field is in the range of Mt, Mt, and 1-2 Mt respectively, the average annual amount is 15.7 Mt (SD 2.2 Mt) of CO 2, 0.06 Mt (SD 5 Mt) of CH 4 and 2 Mt (SD 01 Mt) of N 2 O. The annual amount of GHG emission in term of carbon dioxide equivalent (CO 2eq ) from burning of rice residue in the field varies between 24.4 and 32.6 Mt, the average annual amount is about 27.4 Mt (SD 2.3 Mt). About 40 percent of GHG emission emits from the burning of major rice residue in the rain-fed area. The percentage of GHG emission (in term of CO 2eq ) due to the burning of major rice residue in the field in each is shown in fig 3. The peak period of emission is during March to May which is about 52 percent of GHG emission from burning of major rice residue. In case of burning of minor rice residue (as shown in fig. 4), the peak period of emission is during February to April which is about 61 percent of GHG emission. Fig. 5 shows the percentage of overall GHG emission in each. The temporal distribution of emission from rice residue burning has cyclic shape. The peak period of emission is in May to August which emits about 54% of overall GHG emission. residues burned (Mt) major residue minor residue Total rice residue Aug-98 Feb-99 Aug-99 Feb-00 Aug-00 Feb-01 Aug-01 Feb-02 Aug-02 Feb-03 Aug-03 Feb-04 Aug-04 Feb-05 Aug-05 Feb-06 Aug-06 Feb-07 Aug-07 Feb-08 Aug-08 Feb-09 Aug-09 Figure 2. Monthly amount of rice residue burned in the field between 1998 and 2009 TABLE V THE ANNUAL AMOUNT OF POLLUTANT AND GHG EMISSION FROM RICE RESIDUE BURNING BETWEEN 1998 AND 2008 (MT) Irrigated Rain-fed Total major minor major minor CO CO CH N 2O NO x PM CO 2eq V2-96

5 Percent of GHG emission Figure 3. Percentage of GHG emission from burning of major rice residue Percent of GHG emission Figure 4. Percentage of GHG emission from burning of minor rice residue Percent of GHG emission 3 Figure 5. temporal distribution of GHG emission from rice residue burning IV. CONCLUSION This study estimates the emission from rice field residues burning during year in Thailand using questionnaire survey data and field experiment data. Based on 2006 IPCC guideline method, the emission from agricultural open burning is estimated from the emission factor and the amount of burned rice residue. The emission factor mostly specific for rice residue open burning is obtained from literature review. The amount of burned residue got from the field survey and the questionnaire survey. From the estimation found the burning of rice residue in Thailand is mainly occurred with the major rice residue especially in the rain-fed area, and generally occurred in March to May. About 22 Mt of rice residue is burned annually that emits GHG emission in term of carbon dioxide equivalent approximately 27 Mt. ACKNOWLEDGMENTS The author would like to grateful to The Joint Graduate School of Energy and Environment for research fund. Thanks for office of agricultural economic, Ministry of Agriculture and Cooperatives for supporting the information. Sincerely thank you for the corporation of the farmer for answering the question and permission the author did the experiment in their area. REFERENCES [1] Office of Agricultural Economics (2010) Agricultural statistic 2009 Thailand, pp [2] Suramaythangkoor, T., and Gheewala, S.H. (2008) Potential of practice implementation of rice straw based power generation in Thailand. Energy Policy, doi: /j.enpol [3] Jiaranaikul, K. (2004) Research and Development on the use of rice transplanter for seed production field, Journal of agricultural engineering research, Agricultural department. [4] PCD-Pollution control department (2005) National Master Plan for open Burning Control, Pollution control Department, Ministry of Natural Resource and Environment, Thailand, pp [5] Fungthammasan, B. (2005) Bioenergy and Biofuels utilization in Thailand, The Joint Graduate School of Energy and Environment (JGSEE), presented at UNIDO Vienna, [6] CAO GuoLiang, ZHANG XiaoYe, WANG YaQiang, and Zheng FangCheng (2008) Estimation of emissions from field burning of crop straw in China, Chinese Science Bulletin, 53, (5), pp [7] Shijian Yang, Hongping He, Shangling Lu, Dong Chen, Jianxi Zhu (2008) Quantification of crop residue burning in the field and its influence on ambient air quality in Suqian, China, Atmospheric Environment, 42, pp [8] PCD-Pollution control department (2007) Monitoring and Assessment of Open Burning in Agricultural Areas/Lands, Ministry of Natural Resource and Environment, Thailand. pp [9] IPCC (The Intergovenmental Panel on Climate Changes) (2006) 2006 IPCC Guidelines for National Greenhouse Gas Inventories. [10] Deborah A. Bossio, William R. Horwath, Randall G. Mutters, and Chris van Kessel (1999) Methane pool and flux dynamics in a rice field following straw incorporation, Soil Biology and Biochemistry, 31, pp [11] M. Chandiramani, J. Jones, P.Kosina. (2007) Crop residues management, IRRI-CIMMYT. V2-97