生物聚合物三仙膠於海岸定砂效益評估之研究

In recent years, because of the fast development of economy, high pressure of population and increasing demand of lands make the migration of people toward the seacoast. Unfortunately, even if there are the barriers of windbreaks, the existing rate of the windbreak-seedling becomes extremely low because of the accumulation or abrasion of flying sands in the monsoon season. Therefore, avoiding flying sands plays an important role in the building of windbreaks. This study focuses on the application of Xanthan gum at the seashore areas through probing into the efficiency of sand fixation, application, and germination. The best concentration of application can be inferred from the three inquiries. The results are summarized as follows: First, the uniform distribution of Xanthan gum in the top of soil layers shows the significant efficiency of sand fixation. In the time period test, the protect layers that used 0.05% Xanthan gum is easy to break because the protect strength is low after 2 months. Second, the higher concentration of Xanthan gum used, the harder the Xanthan gum applied. But we have to notice that the lower the concentration of Xanthan gum, the weaker the strength of protect layers. Thus, the weaker protect layers is not strong enough to fix sand. Third, the germination rate descends slightly and the germination is sluggish for the applying concentration of Xanthan gum up to 0.2%. Sprayed the Xanthan gum in the sand with the concentration rises, pH will descends slightly that shows using Xanthan gum in coastal area can buffer the threaten of high pH. It is good for plants . It is suggested that the area which allow vegetation intrude do not use more than 0.2% Xanthan gum on sand fixation. If the water supply is sufficient, the concentration of Xanthan gum can be reduced to 0.05% and the vegetation seeds can be mixed with Xanthan gum to spray. In early stage, the ability of sand fixation of Xanthan gum can decrease the damage of flying sands on the germination of Bermuda grasses. After the germination of Bermuda grasses , the root system of grasses can play the role of sand fixation instead.近年經濟快速發展，在高人口壓力及土地需求漸增的情形下，不得不往濱海地區發展。濱海地區雖有防風林屏障，以減少東北季風的威脅，但在成林過程中常因飛砂堆積或磨損，導致防風林幼苗生存率過低，因此栽植防風林之先驅工作宜以防止飛砂為要務。 本研究將三仙膠在海岸定砂的適用性分為定砂效益、施用效益及發芽效益，綜合探討最佳施用濃度。由施用效益來說，當三仙膠濃度愈濃施用效益愈差，其間有著線性負相關性，但須注意的是當濃度愈低其砂面保護強度亦隨之下降，無法提供有效的定砂保護作用。定砂效益顯示，濃度達0.05%，即具有定砂效果，但在持久性方面，僅施用0.05%的三仙膠溶液在經過兩個月後，易因保護強度不足而出現破壞面。濃度提高至0.2%時，發芽率微幅下降且有發芽遲滯的現象。噴附三仙膠於海砂上，隨著噴附濃度之增加，土壤pH值則隨之微幅下降，顯示三仙膠溶液噴灑在海砂上可以緩和pH值，有利植物生長。 採取植生入侵的區位不建議施作濃度大於0.2%的三仙膠。在有水源補注的區域可使用濃度0.05%的三仙膠溶液混合植生草種進行噴植，利用三仙膠的定砂能力防止幼芽受到飛砂磨傷，待植生成長之後，植群產生定砂作用後，三仙膠的穩定沙丘、防止飛砂的階段性任務已完成，此時進行防風林栽植工作可收事半功倍之效。壹、 前言 1 貳、 前人研究 3 一、海岸變遷之研究 3 二、海岸飛砂特性 4 (一)土壤結殼的影響 5 三、風蝕相關研究 5 四、三仙膠相關研究 6 五、穩定藥劑對土壤穩定效果之相關應用 9 （一）生石灰處理 9 （二）氯化鈣處理 11 （三）矽酸鈉處理 11 （四）混合施用處理 12 （五）土壤團粒化劑處理 12 六、土壤改良 14 六、定砂方法之相關研究 15 （一）植生方法 15 （二）覆蓋 15 （三）土壤水分 16 參、 研究材料與方法 18 一、研究流程 18 二、試驗材料 18 （一）供試土壤 19 （二）三仙膠簡介 19 (三) 供試三仙膠 21 （四）試驗草種 21 三、試驗項目與方法 22 （一）土壤物理性質分析 22 （二）施用效益評估 23 （三）定砂效益 24 （四）種子發芽試驗 28 肆、 結果與討論 30 一、施用效益 30 （一）噴灑入滲深度 30 （二）噴灑直徑調查 30 （三）土壤保濕效益 32 （四）砂面膠結強度調查 33 二、定砂效益試驗 34 （一）抗風蝕試驗 34 （二）耐久度試驗 35 三、發芽試驗 38 （一）種子發芽試驗 38 （二）種子發芽勢 40 四、土壤性質 41 （一）土壤pH值 41 五、最佳濃度決定 42 伍、 結論與建議 44 參考文獻 4