植生缓冲带具缓冲污染物与拦阻泥砂等功效

1、摘要植生緩衝帶具緩衝污染物與攔阻泥砂等功效，為坡地保育最佳處理措施(Best Management Practices, BMPs)之一；惟緩衝帶配置區位會影響耕地面積，用地取得不易。因此，如何在坡地農業規劃上，劃定緩衝綠帶，作為耕地保育及綠美化用地極為重要。本研究回顧水土保持相關法令，萃取需加強保育之環境敏感區內植生綠覆較差之點位，供依法需配置植生緩衝帶之優先區位；另既有農塘或潛在窪蓄等地因有涵養水源、滯洪沉砂、供給農業用水、營造生態環境、提供景觀休閒等多功能之誘因，可鼓勵農民於農塘周遭配置適宜之綠帶，為植生緩衝帶另一優選區位。最後以農業非點源污染模式結合地理資訊系統，檢討優選區位之植生緩衝

2、帶配置效益。油田村陡峭及濱水地區需要植生復育之面積約330公頃（陡峭區位299公頃，濱水區31公頃）。陡峭區位植生復育處理係直接萃取植生覆蓋因子（C）大於0.001之區位模擬植生造林（C = 0.001）；濱水區以10公尺寬度加以探討，針對需改善處（C > 0.1）配置植生緩衝帶（C = 0.1）加以模擬。依陡峭、濱水、以及陡峭與濱水區位需植生復育處理者，利用AGNPS模擬三種處理之集水區泥砂產量、泥砂含氮量、以及泥砂含磷量之單位面積改善效益。環境敏感與窪蓄區位之緩衝帶配置可相輔相成，在功能上若能互為緩衝更可增強緩衝效能。扣除環境敏感區已配置緩衝帶之窪蓄區位，以集水面積及窪蓄量體為篩選條

3、件，可優選集水區需配置植生緩衝帶之窪蓄區位。關鍵詞：窪蓄區位、環境敏感區位、植生緩衝帶AbstractVegetated buffer strips, which employed to intercept sediment and pollutant, are one of the best management practices (BMPs) for slopeland conservation. However, placements of buffer strips could decrease the cultivated lands which results in diffic

4、ult promotion. Therefore, how to delineate the buffer zones for the usage of tillage conservation and greenery is very important. This study reviewed the related acts of soil and water conservation to extract the environmentally sensitive areas of poor vegetation for priority placement of vegetation

5、 buffer strips. In addition, farm ponds and/or potential depression areas are also suitable sites for placement due to the multifunction of water storage, detention and sedimentation, irrigation, ecological enhancement, landscape and leisure. Finally, Agricultural Non-Point Source Pollution Model (A

6、GNPS) coupled with geographical information systems is applied to examine the benefits of placement of vegetated buffer strips.The vegetative restoration areas at the steep (slope55%) and riparian zones (distance to river = 10m) in Youtian Village are about 330 ha (steep 299 ha and riparian 31 ha, r

7、espectively). Steep areas of poor vegetation, vegetated cover index (C) greater than 0.001, were extracted to simulate the benefits of afforest (C = 0.001). Poor vegetation (C > 0.1) of the riparian areas was also simulated to examine the improvement benefits of placement of vegetated buffer stri

8、ps (C = 0.1). According to the different scenarios of improvement (steep areas only, riparian zones only, and both), the benefits of improvement for sediment yield, nitrogen and phosphate content in sediment are simulated by using AGNPS. The functionality of vegetated buffer strips are not exclusive for placed at the environmentally sensitive and/or depression areas. Since the placement of both areas could be more effective, the depression areas where environmentally sensitive areas duplicated were deducted are chosen to priority selection base