土壤pH值與有機質含量對Cr(Ⅲ)之植物毒性及在土壤中型態分佈之影響

The Effect of soil pH and Organic Matter Content on Cr(Ⅲ) Phytotoxicity and Bound Type in Soils

陳秋萍(Chiou-Pin Chen) ； 莊愷瑋(Kai-Wei Juang) ； 林紫慧(Tzu-Huei Lin) ； 李達源(Dar-Yuan Lee)

《臺灣農業化學與食品科學》 47卷6期 (2009/12) Pp. 317-326

https://doi.org/10.6578/TJACFS.2009.036

摘要

土壤中Cr(Ⅲ)之值物毒性可能會由於酸性土壤中Cr(Ⅲ)溶解皮之上升而增加，或是因為土壤中的有機質含量多寡而有所增減。因此，評估不同pH值及有機質含量土壤中之Cr(Ⅲ)植物毒性有其必要性。本研究選取台灣兩種酸性土壤進行試驗。在添加不同含量CaCO3於供試土壤中以調整土壤pH值至4-5、5-6以及6-7三個範圍後，再添加不同濃度Cr(Ⅲ)（0、150、300、500、1000及1500mg/kg）於供試土壤中，並在孵育完成後供後續試驗使用。本研究利用Chelex100樹脂評估添加不同含量CaCO2土壤中Cr(Ⅲ)之有效性，並進行小麥盆栽試驗以評估其植物毒性。此外，本研究亦利用序列抽出試驗來測定添加Cr(Ⅲ)土壤中之Cr(Ⅲ)型態，以闡釋其型態分佈與植物毒性之關係。研究結果顯示，Chelex100樹脂之銘抽出量會隨著兩種供試土壤pH值的降低而增加，而小麥之株高、地上部乾重及根部乾重則隨著土壤pH值的降低而減少，意即Cr(Ⅲ)之植物毒性會隨著土壤pH值的下降而提高。生長於有機質含量較高的內埔系土壤中之小麥所受到之毒害較生長於有機質含量較低之平鎮系土壤者為小。序列抽出結果顯示，內埔系土壤中之有機結合態鉻含量較平鎮系土壤中高出許多，意即添加於內埔系土壤中之Cr(Ⅲ)可能大量與土壤中之有機質結合，並與之形成有機複合物，因而使Cr(Ⅲ)之植物毒性降低。

關鍵字

Chelex100樹脂 ； 植物毒性 ； 序列抽出

並列摘要

The phytotoxicity of Cr(Ⅲ) was affected by solubility of Cr(Ⅲ) in acidic soil and the contents of organic matter in soil; thus evaluation of phytotoxicity of Cr(Ⅲ) in soil with various soil pH conditions and organic matter content is necessary. Two acidic soils (Neipu and Pinchen) were adjusted to three pH ranges (4-5, 5-6, and 6-7) and then treated with six Cr(Ⅲ)-spiked levels (0, 150, 300, 500, 1000, and 1500 mg/kg). Chelex 100 resin was used to extract Cr(Ⅲ) from soils with different CaCO3 addition, and wheat seedling experiment was conducted for illustration of Cr phytotoxicity. Additionally, the form of Cr(Ⅲ) in Cr(Ⅲ)-added soils were subjected to extraction and determination using the procedure of sequential extraction. The results showed that the amount of Cr(Ⅲ) extracted increased with increasing Cr(Ⅲ) concentration and decreasing pH of studied soils, and the injury of wheat seedlings increased with decreasing soil pH. It indicated that the phytoxicity of Cr(Ⅲ) increased with decreasing soil pH. Organic matter bound Cr in Neipu soil is much higher than that in Pinchen soil, which indicated that phytotoxicity of Cr(Ⅲ) in Pinchen soil was greater than that in Neipu soil due to that the Cr(Ⅲ)-complex could be formed with large amount of organic matter in the Neipu soil, thus reducing the phytotoxicity of Cr(Ⅲ).

並列關鍵字

Chelex 100 resin ； phytotoxicity ； sequential extraction