| Abstrakt: |
Purpose: The increasing demand for livestock products is the main driver of expansion of maize cultivation areas in Thailand. However, its environmental impacts, especially those associated with greenhouse gas (GHG) emissions in different cropping seasons, remain unclear. Therefore, this study aimed to estimate the carbon dioxide equivalences (CO2-eq) occurring during various weather seasons (early rainy, late rainy, and dry seasons) of maize production. Life cycle costing (LCC) associated with grain production were also evaluated. Methods: A total of 131 plantation land plots in dominant areas of maize plantation in Chiang Rai, Nan, Tak, Phetchabun, and Loei Provinces were selected for data collection. The system boundaries included the cultivation, grain drying, and transportation of grain to feed mills. A carbon movement categorization method was employed to determine CO2 equivalences including carbon emissions, fixation, and reduction. The functional unit used for CO2 equivalences evaluation was either kg CO2-eq/ha or kg CO2-eq/ton grain. LCC was used as analytical tool to examine the total cost and net profit of maize production among different cropping seasons. Results and discussion: Total GHG emissions from maize production were found to be an average of 429 ± 27 kg CO2-eq/ton grain. The highest emissions among different seasons of maize production were during the dry season which were 2970 ± 792 kg CO2-eq/ha. However, no significant difference was observed between total emissions per unit of grain produced in the different seasons. The results of LCC of maize grain production revealed that the net economic benefits per carbon emitted during the early rainy, late rainy, and dry seasons were 0.44, 0.49, and 0.50 USD/kg CO2-eq, respectively. These confirmed that the dry season exhibited greater economic benefits compared with rainy seasons. Moreover, the carbon fixation efficiency was computed to be 79.0–80.2%, indicating that maize production still emits carbon to the atmosphere. Conclusions and recommendations: This study evaluated CO2 emissions from different cropping seasons of maize production to identify the most suitable cropping season in terms of lower CO2 emissions and higher net economic benefit. These findings may be used to effect better government policy on reducing GHG emissions and managing land use for maize cultivation in Thailand. [ABSTRACT FROM AUTHOR] |
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