[A-CG39] グローバル炭素循環の観測と解析

[ACG39-P09] Agricultural strategies in a changing climate: do elevation and farming practices influence carbon sequestration in the tea farms of Taiwan?

*Yu-Ching yang¹、Kuo-Jung Chao²、Hsing-Juh Lin³、Guo-Zhang Michael Song¹ (1.Department of Soil and Water Conservation, National Chung Hsing University, Taichung 402, Taiwan.、2.International Master Program in Agriculture, National Chung Hsing University, Taichung 402, Taiwan、3.Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan)

キーワード：carbon sequestration, economic crops, tea plantations carbon sink

To mitigate climate change, it is essential to identify agricultural management practices that balance economic viability with carbon sequestration potential. Our study focused on Camellia sinensis, a key crop in Taiwan’s tea industry, which, as a woody perennial, offers greater carbon sequestration potential than annual crops. Our research investigated the influence of elevation and farming practices on carbon sequestration in tea farms. We surveyed 21 tea farms in central Taiwan across three elevation ranges (300–500 m, 500–1000 m, and 1000–1500 m) and two farming practices (ecological and conventional). We assessed carbon storage (aboveground tea plant biomass and litter carbon stocks), carbon inputs (aboveground biomass growth and fertilization), and carbon removals (tea harvest and litter decomposition). Kruskal-Wallis tests revealed significant differences in aboveground carbon storage (p = 0.006), litter carbon storage (p = 0.009), net carbon growth (p = 0.036), and aboveground carbon removal (p = 0.036) across elevations. Mid-elevation farms exhibited lower values of these four attributes than low- and high-elevation sites, likely due to more intensive pruning by farmers, which reduced aboveground biomass. Net carbon growth rate approached significance for both elevation (p = 0.061) and farming practice (p = 0.064), showing a decreasing trend with increasing elevation, possibly due to lower temperatures at higher altitudes limiting tea plant growth. Using linear mixed-effects models, we analyzed the effects of seven fixed factors (temperature, temperature squared, rainfall, farming practice, elevation, tea variety, and tea plant age) and two nested random effects (the location of farms and crop rows) on net aboveground carbon growth rate. Temperature emerged as the most influential factor. Under future climate change scenarios, while short-term warming may enhance net carbon growth in tea farms, excessive temperature increases could slow growth or even lead to plant mortality.