GHG Emissions and Carbon Sequestration in Coastal Bambusa edulis Shelterbelts with Biochar and Organic Fertilizer

This study evaluated the seasonal greenhouse gas (GHG) emissions and carbon assimilation of Bambusa edulis under four soil amendment treatments—control (C), biochar (B), fertilizer (F), and biochar plus fertilizer (B+F)—in a coastal shelterbelt system in southwestern Taiwan. Over a 12-month monitoring period (August 2023–July 2024), static chamber techniques and portable photosynthesis systems were used to measure CO₂ and N₂O fluxes as well as net photosynthetic assimilation. Results showed that the fertilizer-only (F) treatment produced the highest CO₂ (up to 4.0 kg m⁻² season⁻¹) and N₂O emissions (peak at 160.73 ± 96.22 g CO₂e m⁻² in summer), but also achieved the highest seasonal carbon assimilation (up to 18.5 kg CO₂ clump⁻¹ season⁻¹). In contrast, the biochar-only (B) treatment exhibited lower GHG emissions—reducing N₂O by 43.3% in summer and 54.3% in autumn compared to F—while maintaining moderate carbon uptake. The B+F treatment showed intermediate performance, suggesting potential synergistic effects. Control plots had the lowest emissions and assimilation rates, with seasonal uptake dropping to 1.8 kg CO₂ clump⁻¹ in autumn due to drought stress. Soil CO₂ flux was significantly correlated with soil temperature (r = 0.63, p < 0.01) and moisture (r = 0.45, p < 0.05), while N₂O flux had a strong positive correlation with soil moisture (r = 0.71, p < 0.001). The findings underscore the trade-off between nutrient-driven productivity and GHG intensity and demonstrate that optimized organic and biochar applications can enhance photosynthetic carbon gain while mitigating emissions. This study provides empirical evidence for bamboo’s potential role in climate mitigation, carbon offset strategies, and ESG-aligned nature-based solutions. The data serve as a baseline for incorporating bamboo shelterbelts into Taiwan’s national GHG accounting and carbon neutrality roadmap.