添加稻殻炭對泥岩土壤沖蝕潛勢及百慕達草萌芽之影響

The Effects of Rice Hull Biochar Application on Soil Erosion Potential and Germination of Bamuda Grass in Mudstone Soils

簡維信(Wei-Hsing Chien)

指導教授 ： 簡士濠

國立屏東科技大學/工學院/水土保持系所/碩士(2013年)

https://doi.org/10.6346/NPUST.2013.00162

摘要

臺灣位熱帶與亞熱帶交界處，乾濕季分明，雨季則有颱風及梅雨對地表造成沖蝕，加上近年又因氣候變遷，易造成極端降雨事件進而加劇沖蝕。泥岩(mudstone)為臺灣地區土壤沖蝕最嚴重的土壤，土壤貧脊且植物不易於上生長，屬一惡地。本研究目的在於利用農業廢棄物回製成之有機碳資材，添加致泥岩土壤中，希望可改善泥岩土壤物化性質、降低沖蝕潛勢與提升植物生長之效益。生物炭(biochar)為高含碳物質(≧30 %)，其特性為多孔性及具高比表面積。添加生物炭致土壤中不僅可提高土壤碳含量，亦可有效提升土壤保肥能力與作物生產力。以700 ℃及400 ℃兩種溫度燒製而稻殼炭，分別添加0 %、2.5 %、5 %和10 %不同比例於供試土壤中，並培育6個月，每3週固定測定土壤孔隙率、飽和水力傳導度、團粒粒徑變化、土壤水分特定曲線、土壤反應、電導度、有機碳含量、陽離子交換容量、鹽基飽和度與微生物生質碳等土壤物化性質。培育最終亦測定土壤沖蝕量、土壤入滲量與地表逕流量。百慕達草萌芽部分土壤硬度及種子發芽數。試驗結果顯示，添加稻殼炭時，土壤孔隙率隨施用率增加而顯著提升；於最高施用量(10 %, w/w)下，孔隙率顯著增加1.4倍以上；然而，不同溫度製備之稻殼炭在對土壤孔隙度之影響上並無顯著差異。團粒穩定度700 ℃及400 ℃稻殼炭添加量10 %最佳，約BK培育6.4倍；土壤水分特性曲線700 ℃及400 ℃稻殼炭添加量10 %最佳；土壤反應下降到4.7-3.3；電導度兩種稻殼炭添加量10 %最低約15 ds/m；有機碳含量皆為1.5 %左右；陽離子交換容量個處理約為10 cmol (+) kg-1沒明顯差異；鹽基飽和度皆為100 %。土壤沖蝕量方面，本研究於降雨強度為80 mm/hr，且坡度為10∘及20∘之模擬條件下進行沖蝕試驗，土壤沖蝕量明顯隨稻殼炭之施用率增加而顯著降低，分別降低30-40 %、80-84 %和89-91 %。不同溫度製備之稻殼炭施用對土壤沖蝕量亦無顯著差異，進一步顯示該兩溫度製備對稻殼炭特性影響不大。百慕達草萌芽部分，土壤硬度於稻殼炭最高添加量(10 %)下，低於10 mm，顯示10 %以上之施用量，土壤硬度方適合種子發芽生長。種子發芽試驗結果顯示，施用10 %之400 ℃稻殼炭可使電導度降至8.5 ds/m以下；同時，淋洗試驗亦顯示該處理下，僅需以最少量之水淋洗，即可使植生發芽，同時達到最高發芽株數(36顆)。本試驗結果明顯證實添加稻殼炭對泥岩之土壤物化性質、土壤沖蝕潛勢與百慕達草萌芽影響具改善效果。

關鍵詞：泥岩、生物炭、土壤可蝕性。

關鍵字

泥岩 ； 生物炭 ； 土壤可蝕性

並列摘要

Taiwan is located at the boundary between subtropical and tropical area. Relatively heavy rainfall and several typhoons visiting during wet season (May to October) are major reason to result in serious soil erosion in Taiwan. Recently, violent rainfall due to global climatic change further leads to more severe erosion events. Mudstone soil is one of the soils with the most serious erosion situation in Taiwan, which is also called badland landscape. In this study, biochar, recycled from agricultural waste was used as an amendment to improve physical properties and erosion potential of the mudstone soils. Rice hull biochar used here was characterized by high carbon contents, porosity and specific surface area, which was incorporated into the mudstone soil with different application rates of 0 %, 2.5 %, 5 % and 10 % (wt/wt). In addition, the biochars pyrolized with 400 and 700 were used and then incubated six months. The soil samples were collected at 0, 21, 42, 63, 84, 105 and 136 and 147 days for analysis of soil properties, including pH, cation exchange capacity (CEC), base saturation percent (BS), bulk density, porosity, saturated water conductivity (Ksat), moisture retention, penetration resistance, soil losses and germination ratio of Bamuda Grass. The experiment results indicated that applying biochar improved the physicochemical properties of the mudstone soils. As comparison with the control (i.e., no biochar), increased porosity by 1.2 times at least, increased Ksat obviously, and increased the mean weight diameter (MWD) of soil aggregates by 1.5 times. The improvements were increased with application rates. Except for porosity, the other physical properties were better improved by rice hull biochar made of 400 ℃. Furthermore, regardless of slope gradients of 10° and 20°, incorporating biochar into the soil significantly reduced soil loss by 30 %, 80 % and 90 % at 2.5 %, 5 % and 10 % application rates, respectively, compared with the control. For germination ratio in the control and the amended soils, Application of the 700 ℃ biochar performed better than 400 ℃ one. Form our results, a 10 % application rate of biochar by a 700 ℃ pyrolysis temperature is considered as suitable for highly weathered soil because this application rate efficiently improves soil physiochemical properties and reduces soil loss.

Key words：mudstone, biochar, soil erodibility

並列關鍵字

mudstone ； biochar ； soil erodibility

參考文獻

3. 李德河，紀雲曜，田坤國，1994，「泥岩之基本特性及泥岩邊坡之保護措施」，地工技術雜誌，第48卷，第35-47頁。

10. 陳時祖，2000a，「臺灣西南部泥(頁)岩之物化地質特性」，臺灣泥岩生態研討會，第1-12頁。

14. 陳慶雄，謝豪榮，1986，「穩定藥劑處理對紅土與青灰泥岩邊坡穩定效果之研究」，水土保持學報，第17卷，第160-180頁。

15. 黃俊義，1986，「臺灣坡地土壤沖蝕性及流失量之推估」，中華水土保持學報，第17卷，第139-154頁。

17. 簡士濠，江介倫，王建昇，張庠睿，2012，「添加生物炭對酸性紅壤肥力之影響」，農業工程學報，第58卷，第4 期，第15-22頁。