稻藁掩埋處理對水田溫室氣體排放影響之研究

為評估是否可藉由將收穫後的稻藁切碎掩埋入土，以協助減少國家溫室氣體的排放量，本研究利用一個可以模擬水田生態系中碳和氮之動態變化的電腦模式，進行長期將稻藁掩埋入土或將稻藁移除兩種作法對水田溫室氣體排放影響的模擬研究。模擬結果指出，水稻收穫後將稻藁切碎掩埋入土的作法，雖然在實施初期可以因為土壤中有機物含量增加而減少水田溫室氣體的淨排放量，然而土壤有機物含量的增加速率會因趨近平衡而逐年降低，且暖化潛勢較高之CH4在湛水期間的釋放量卻因土壤中有機物含量增加而逐年增加。將稻藁掩埋入土作法在中～粗質地土壤連續實施約10年（細質地土壤實施約20年）後，其溫室氣體的淨排放量反而超過不將稻藁掩埋入土的作法。因此，將稻藁掩埋入土的作法並不是能降低水田溫室氣體淨排放量的「無悔」措施。

關鍵字

全球暖化；溫室氣體；稻藁掩埋

並列摘要

Simulation studies were conducted, using a computer model which considered the dynamic changes C and N in paddy ecosystems, to evaluate the potential of decreasing national greenhouse gases (GHG) emissions by incorporating shredded rice straws into soils after harvest. Results indicated that the net GHG emission from paddy fields could be decreased in the beginning, as results of the rapid increasing of soil organic carbon (SOC) content through the rice straws incorporation. However, the atmospheric CO2 sequestering capability would be gradually reduced while the SOC contents were reaching equilibrium, but the amounts of CH4 emitted during flooding periods were increased due to the increasing of SOC content. Considering the higher global warming potential of CH4, the net amount of GHG emitted due to rice straw incorporation would exceed those not incorporating the rice straws after practicing the measures for more than 10 years in medium to coarse textured soils (20 years for fine textured soils). Therefore, rice straw incorporation can not be considered as a no-regret measure to decrease the amount of GHG emission from paddy fields.

並列關鍵字

Global warming ； Greenhouse gases ； Rice straw incorporation

國際替代計量

稻藁掩埋處理對水田溫室氣體排放影響之研究

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