| 水稻不同生育期根际及非根际土壤砷形态迁移转化规律 |
| 摘要点击 3098 全文点击 1591 投稿时间：2014-08-22 修订日期：2014-09-28 |
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| 中文关键词 根际土壤 非根际土壤 水稻 TCLP 砷 |
| 英文关键词 rhizosphere soil non-rhizosphere soil rice TCLP arsenic |
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| 中文摘要 |
| 选取湖南某矿区污染稻田土,以盆栽试验的方式,采用美国 TCLP(toxicity characteristic leaching procedure) 和砷形态分析分级测定法,研究了水稻 (Oryza sativa L.)各生育期(分蘖期、拔节期、孕穗期、灌浆期、成熟期)根际和非根际土壤中砷的赋存形态及转化规律. 结果表明: 1随着水稻生育期的延长, 根际及非根际土壤pH值和砷TCLP提取态含量均逐渐上升,且非根际土壤pH值和砷TCLP提取态含量均高于同时期根际土壤. 2水稻各生育期根际和非根际土壤中交换态砷(AE-As)含量均低于水稻种植前,并随着水稻生育期的延长逐渐上升. 与水稻种植前相比,铝型砷(Al-As)、铁型砷(Fe-As)和钙型砷(Ca-As)含量在水稻种植后逐渐上升,但并不显著. 残渣态砷(O-As)和总砷(T-As)含量在水稻种植后逐渐下降,在根际土壤中下降了37.30%和14.69%,在非根际土壤中分别下降了31.38%、8.67%. 3在水稻不同生育期,土壤中各形态砷含量均表现为:残渣态>铁型砷>铝型砷>钙型砷>交换态砷. 在pH值为5.0~5.8的范围内,各砷形态和砷TCLP提取态含量与pH值之间大都呈极显著或显著正相关,但根际土壤中钙型砷与pH值的相关关系较差. |
| 英文摘要 |
| Speciation and bioavailability of arsenic in the rhizosphere and non-rhizosphere soils at different growth stages (tillering stage, jointing stage, booting stage, filling stage and maturing stage) of rice (Oryza sativa L.) were studied using toxicity characteristic leaching procedure (TCLP) and arsenic speciation analysis. Pot experiments were conducted and the soil samples were taken from a certain paddy soil in Hunan Province contaminated by mining industry. The results showed that: ①With the extension of rice growth period, pH values and TCLP extractable arsenic levels in the rhizosphere and non-rhizosphere soils increased gradually. Soil pH and TCLP extractable arsenic levels in non-rhizosphere soils were higher than those in the rhizosphere soils at the same growth stage. ② At the different growth stages of rice, contents of exchangeable arsenic (AE-As) in rhizosphere and non-rhizosphere soils were lower than those before the rice planting, and increased gradually with the extension of the rice growing period. Contents of Al-bound arsenic (Al-As), Fe-bound arsenic (Fe-As) and Ca-bound arsenic (Ca-As) increased gradually after rice planting, but not significantly. Residual arsenic (O-As) and total arsenic (T-As) decreased gradually after rice planting, by 37.30% and 14.69% in the rhizosphere soils and by 31.38% and 8.67 % in the non-rhizosphere soils, respectively. ③At the different growth stages of rice, contents of various forms of arsenic in the soils were in the following order: residual arsenic (O-As)>Fe-bound arsenic (Fe-As)>Al-bound arsenic (Al-As)>Ca-bound arsenic (Ca-As)>exchangeable arsenic (AE-As). In the pH range of 5.0-5.8, significant positive linear correlations were found between most forms of arsenic or TCLP extractable arsenic levels and pH values, while the Ca-bound arsenic was poorly correlated with pH values in the rhizosphere soils. |
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