不同灌溉方式茶樹碳匯通量之機制解析與比較

Abstract

本研究旨在探討不同灌溉模式對茶園碳循環動態之影響，重點聚焦於宜蘭地區田間實際條件下，土壤有機碳（Soil Organic Carbon, SOC）儲存與二氧化碳（Carbon Dioxide, CO₂）通量之量化評估。研究採用密閉式靜態罩（Closed Static Chamber, CSC）進行原位氣體通量監測，並配合季度性土壤採樣，分析氣態碳排放與SOC累積變化，涵蓋三種土地利用情境：全灌溉茶園、雨養式茶園及廢耕坵塊。 實驗結果顯示，灌溉管理顯著影響茶園碳循環過程。相較於其他處理，全灌溉地塊表現出較低之CO₂排放與較高之SOC累積，展現出更強的碳封存潛能；雨養地塊則呈現通量波動性高與碳儲存效率低的特徵；廢耕地作為未受人為干預之對照，反映自然放任狀態下的土壤碳行為。儘管多年生作物系統在結構與操作上存在一定挑戰，CSC方法仍證實具備可行性與穩定性，適用於長期監測茶園溫室氣體排放。 灌溉在茶園碳循環調節中扮演關鍵角色，能同時提升作物生產力與土壤碳儲存。研究結果凸顯自然本位灌溉策略於氣候緩解上的潛力，並為永續土地管理提供具體指引。所建立之在地碳監測架構亦展現多年生農作系統整合農業發展與環境目標的可行性。

This study investigates how different irrigation regimes influence carbon cycling in tea plantations, with a focus on quantifying soil organic carbon (SOC) storage and carbon dioxide (CO₂) fluxes under field conditions in Yilan, Taiwan. Through in-situ field monitoring using the closed static chamber (CSC) method and quarterly soil sampling, we examined gaseous carbon emissions and SOC accumulation in three distinct plots: a well-irrigated tea plantation, a rainfed tea field, and an abandoned tea plot. The results reveal clear differences in carbon behavior under varying irrigation practices. Well-irrigated tea plantations demonstrated lower CO₂ emissions and higher SOC levels, indicating a stronger potential for carbon sequestration. Rainfed plots, by contrast, exhibited greater flux variability and lower carbon retention, while abandoned fields served as baselines for unmanaged soil conditions. The CSC method, despite structural challenges in perennial systems, proved to be a practical and consistent tool for long-term field monitoring. Irrigation plays a pivotal role in regulating carbon cycling in tea plantations, promoting both productivity and soil carbon storage. These results highlight the potential of nature-based irrigation for climate mitigation and offer guidance for sustainable land management. The localized carbon monitoring framework further demonstrates how perennial systems can integrate agricultural and environmental objectives.