挺水植物根系發展對濱水地區土壤沖蝕之影響

本研究進行種植四種挺水植物的植物區與裸露土壤區的沖蝕實驗，以雷射掃描分析地形變化及沖蝕量，洗根測量瞭解植物根系發展情況，用以探討挺水植物對濱水區土壤沖蝕之影響。結果顯示，單葉鹹草有最佳存活率，且根系最長。在種植香蒲、單葉鹹草及水丁香之試區與裸露區相比都能減少沖蝕量；且單葉鹹草及水丁香區沖蝕量低，植物根系長，抗沖蝕能力較佳。考量植物存活率，單葉鹹草應適合推廣作為改善濱水區土壤沖蝕之植生復育工法物種。

關鍵字

土壤沖蝕；挺水植物；根系長度；雷射掃描地形

並列摘要

In this study, erosion experiments were conducted using vegetated plots with four species of emergent vegetation and bare-soil plots in a recirculating flume. To investigate the effects of emergent vegetation on soil erosion in riparian regions, erosion topography and eroded soil mass were obtained using laser-scanned images, and root system development of the emergent plants was analyzed by measuring root parameters after the root washing process. The results showed that Cyperus malaccensis (i.e., shortleaf galingale) demonstrated the highest survival rate and developed the longest root system. The vegetated plots with Typha orientalis (oriental cat-tail), C. malaccensis, and Ludwigia octovalvis (lantern seedbox (H)) exhibited smaller eroded soil masses than did the bare-soil plots. C. malaccensis and L. octovalvis exhibited higher erosion resistance than the other species because the vegetated plots with these species exhibited less soil loss than the plots with the other species, and the plants exhibited greater development of root systems than the other species. Considering the survival rate, C. malaccensis was the most suitable species among the four species for increasing erosion resistance of riverbanks in riparian regions.