Energy and environmental impact analysis of rice cultivation and straw management in northern Thailand.

Rice cultivation and energy use for rice production can produce the environmental impacts, especially related to greenhouse gas (GHG) emissions. Also, rice straw open burning by farmers generally practiced after harvesting stage in Thailand for removing the residues in the rice field is associated with emissions of air pollutants, especially particulate matter formation that affects human health and global climate. This study assessed the environmental burdens, consisting of GHG emissions, energy use, and particulate matter formation (PM10), from rice cultivation in Thailand by life cycle assessment (LCA) and compared the environmental burdens of rice straw management scenarios: open burning, incorporation into soil, and direct combustion for electricity generation. The data were collected from the rice production cooperative in Chiang Mai province, northern Thailand, via onsite records and face-to-face questionnaires in 2016. The environmental impacts were evaluated from cradle-to-farm gate. The results showed that the total GHG emissions were 0.64 kg CO2-eq per kilogram of paddy rice, the total energy use was 1.80 MJ per kilogram of paddy rice and the PM10 emissions were 0.42 g PM10-eq per kilogram of paddy rice. The results of rice straw management scenarios showed that rice straw open burning had the highest GHG and PM10 emissions. However, rice straw utilization by incorporation into soil and direct combustion for electricity generation could reduce these impacts substantially.

Life cycle GHG evaluation of organic rice production in northern Thailand.

Greenhouse gas (GHG) emission is one of the serious international environmental issues that can lead to severe damages such as climate change, sea level rise, emerging disease and many other impacts. Rice cultivation is associated with emissions of potent GHGs such as methane and nitrous oxide. Thai rice has been massively exported worldwide however the markets are becoming more competitive than ever since the green market has been hugely promoted. In order to maintain the same level or enhance of competitiveness, Thai rice needs to be considered for environmentally conscious products to meet the international environmental standards. Therefore, it is necessary to evaluate the greenhouse gas emissions throughout the life cycle of rice production in order to identify the major emission sources and possible reduction strategies. In this research, the rice variety considered is Khao Dawk Mali 105 (KDML 105) cultivated by organic practices. The data sources were Don-Chiang Organic Agricultural Cooperative (DCOAC), Mae-teang district, Chiang Mai province, Thailand and the Office of Agricultural Economics (OAE) of Thailand with onsite records and interviews of farmers in 2013. The GHG emissions were calculated from cradle-to-farm by using the Life Cycle Assessment (LCA) approach and the 2006 IPCC Guideline for National Greenhouse Gas Inventories. The functional unit is defined as 1 kg of paddy rice at farm gate. Results showed that the total GHG emissions of organic rice production were 0.58 kg CO2-eq per kg of paddy rice. The major source of GHG emission was from the field emissions accounting for 0.48 kg CO2-eq per kg of paddy rice, about 83% of total, followed by land preparation, harvesting and other stages (planting, cultivation and transport of raw materials) were 9, 5 and 3% of total, respectively. The comparative results clearly showed that the GHG emissions of organic paddy rice were considerably lower than conventional rice production due to the advantages of using organic fertilisers.