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標題: A Study of Conservation Grass on the Restoration of Cd- contaminated Soils
作者: Lin, Chih-ju
關鍵字: Cd-contaminated soils
Conservation grass
Soil and water conservation
出版社: 水土保持學系
摘要: 台灣地區農田受鎘污染漸趨嚴重,造成稻米中鎘含量過高,而危害人體健 康。政府目前對於鎘污染地之處理,大多採用廢耕方式,或輔導種植非食 用作物,台灣地小人稠、資源寶貴,污染地之復育工作刻不容緩。本研究 選取常用之復育草種,包括百慕達草、地毯草、類地毯草、假儉草、百喜 草及五節芒等草種,分別施以不同鎘濃度處理,調查其生長情形,藉以篩 選各草種在鎘污染地中生長較好者,以及對鎘吸收度較佳者,期對鎘污染 地做復育之工作,並供環境復育之參考。試驗結果摘述如下:供試草種發 芽率受鎘處理並無顯著影響。草種受鎘毒害之臨界濃度皆在50ppm以下, 草種受鎘污染之性狀大致相同,植株具矮小、新葉黃化、根細少等癥狀, 鎘濃度愈高癥狀愈明顯。植體之株高、根長、乾重等與鎘處理呈顯著負相 關。鎘處理會抑制植體養分之吸收量,使植株生長因缺乏養分而致生長不 良。惟百慕達草對N、P、K、Na、Ca、Mg、Fe、Cu等元素之吸收,各處理 間未達顯著水準,差異不大,百慕達草對Mn之吸收量與鎘處理濃度呈顯著 負相關,而對Zn之吸收量呈顯著正相關。供試草種中,地毯草、類地毯草 、百喜草與五節芒等對鎘之耐受度較差,百慕達草及假儉草,植株受鎘處 理的影響不大,能吸收土壤中之鎘,對鎘污染土壤有顯著的復育效果,其 中以百慕達草對鎘之耐受度及吸收度最佳,為鎘污染地適當之復育草種。
Paddy fields contaminated by Cd in Taiwan need to be more concerned. High concentration of Cd in rice grains is harmful to human health. Cd-contaminated fields are often abandoned or being changed to plant non-edible crops. It is urgent to restore the contaminated environment due to limited nature resources. This research selects conservation grasses including Bermuda grass, Carpet grass, Carpet grass(Axonopus affinis Chase), Centipede grass, Bahia grass, Japanese silver grass etc. Every grass treated with different concentrations of Cd and then survey growth of grasses. The purpose of this paper is to find the suitable conservation grass for the reclamation of Cd- contaminated soils and establish the data base of conservation grass for the use of Cd-contaminated soils. The results are summarized as follows:Germination percentage for tested grasses are not affected by the concentration of Cd. Tested grasses are all showing the same symptoms of toxicity at the 50ppm treatment of Cd concentration. Stunted growth, chlorosis and undeveloped root systems are the major symptoms and can be identified obviously at high concentration of Cd added. Plant height, root length, and dry weight of grasses are decreased significantly by increasing Cd concentration. High Cd concentration results in poor nutrients uptake and stunted growth for tested grasses except Bermuda grass. Bermuda grass shows no significant difference on nutrients uptake but Mn and Zn under Cd treatment. Increasing Cd concentration inhibits Mn-uptake, while enhances Zn-uptake for Bermuda grass tissue. Comparing to Bermuda grass and Centipede grass, Carpet grass, Carpet grass(Axonopus affinis Chase), Bahia grass, and Japanese silver grass showed worse tolerance to Cd-contamiinated soils. Bermuda grass and Centipede grass show no significant difference in growth among the Cd- contaminated levels and both have good ability to absorb Cd element from the soils. Both of them can be as the suitable grasses (especially Bermuda grass) for the use of restoration of Cd-contaminated soils.
Appears in Collections:水土保持學系



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