水稻耕種方法與溫室氣體排放之研究

因應氣候變遷於全球之影響，為降低全球暖化速度，國際間投力於2050淨零碳排，台灣各產業也積極響應，水稻產業與淨零碳排之關係為值得吾人探討的課題。本研究針對我國主要糧食作物稻米進行溫室氣體排放之調查，並採用農民現行的三種水稻農法進行比較:慣行農法、乾溼交替(alternate wetting and drying, AWD)、益生菌水稻強化栽培系統(system of probiotic rice intensification, SPRI)，本研究採取現地訪查的方式了解各農法於栽培期間(育種至收割)所需使用之機具、流程與肥料，並藉由蒐集文獻取得甲烷及氧化亞氮於水稻田間的排放係數，進一步計算各農法栽培期間之溫室氣體排放。計算結果顯示，水稻耕作使用SPRI農法之溫室氣體排放最低值，其二氧化碳當量為2370.63公斤，與慣行農法之二氧化碳當量7786.33公斤比較減少了70%，與AWD農法之二氧化碳當量3918.11公斤比較則減少了39%，為更了解農法變化下溫室氣體減少的原因，本研究將溫室氣體排放因子分為運輸能源、物料、肥料、機械能源及灌溉等六大部分，探討各因子所占影響百分比。結果可知，稻田溫室氣體排放受灌溉管理影響最為明顯，其中SPRI灌溉用水的改變得以減少慣行用水稻田二氧化碳當量排放之91%，而SPRI施肥條件的改變得以減少慣行施肥二氧化碳當量排放之60%。由本研究結果發現，農法的改變對於水稻栽培溫室氣體排放值的影響甚大，因此若將農法進行調整可以在產量不改變的狀況下，讓育種至收割期間溫室氣體的排放量降低，對地球的溫室效應有相當程度的貢獻。

關鍵字

益生菌水稻強化栽培系統；全球暖化；溫室效應；二氧化碳排放；甲烷；氧化亞氮

並列摘要

To reduce the rate of global warming in response to the global impact of climate change. International investment in net-zero carbon emissions by 2050 . Various industries in Taiwan also responded positively to the idea that the relationship between rice industry and net zero carbon emissions is a subject worthy of my exploration.This study investigates the greenhouse gas emissions of rice, a major food crop in Taiwan, and uses three types of farmers' current rice farming methods for comparison: conventional farming, alternate wetting and drying (AWD), an a system of probiotic rice intensification (SPRI ).The study was conducted by means of on-site visits to uderstand the tools, processes and fertilizers required for each agricultural method during cultivation, and the values of methane and nitrous oxide emissions in rice fields were also obtained through literature collection to calculate of greenhouse gas emissions for each agricultural method. The calculation results show that the lowest greenhouse gas emission value is the SPRI agricultural method for rice cultivation, the CO2 eq of this is 2370.63 kg. This is a 70% reduction compared to the conventional agricultural method of 7786.33 kg of CO2 eq, and 39% reduction compared to the AWD method of 3918.11 kg of CO2 eq. To understand the reasons of reducing greenhouse gases with changing agricultural practices. This study divides the greenhouse gas (GHG) emission factors into six parts: transportation energy, material, fertilizer, mechanical energy and irrigation, to explore the percentage of influence of each factor. The results of the study show that the main impacts are irrigation water and fertilizer use, greenhouse gas emission from rice field is most significantly affected by irrigation management. Of this, changes in SPRI irrigation water reduced 91% of CO2-equivalent emissions from conventional paddy fields and changes in fertilizers by 60 %. Greenhouse gas emission differences are mainly affected by irrigation water and fertilizer use. This study found that use different agricultural methods had a significant impact on the value of greenhouse gas emissions from rice cultivation. Therefore, if the farming method is adjusted, the greenhouse gas emissions during cultivation can be reduced without changing the yield, and contribute to the Earth's greenhouse effect.