| 不同开垦年限湿地土壤铁变化特征研究 |
| 摘要点击 5066 全文点击 2661 投稿时间：2007-04-10 修订日期：2007-05-31 |
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| 中文关键词 沼泽湿地 土壤铁 开垦年限 三江平原 |
| 英文关键词 marsh wetland soil iron ages of reclamation Sanjiang Plain |
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| 中文摘要 |
| 以三江平原不同开垦年限的湿地土壤为对象，研究了土壤全铁含量、氧化铁游离度、活化度和络合度的时空变化趋势.结果表明，耕层(0～20 cm)土壤较中下层(20～100 cm)土壤、开垦初期(0～1 a)较开垦后期(1～25 a)铁所受影响更为显著.土壤全铁与有机质呈极显著负相关，相关系数为-0.620，而与全磷和pH值的相关程度较低.土层1(0～10 cm)全铁含量于开垦前7 a快速增长，13 a后趋于平稳；而土层2(10～20 cm)的快速增长期为8 a，15 a后进入平稳期.土层1比土层2的响应时间更短，规律性更强.土壤氧化铁的游离度在开垦之后迅速升高，而后降低再升高.活化度和络合度随开垦年限的增加都呈指数衰减趋势，其中土层1的活化度在开垦前4 a迅速降低，6 a后趋于平稳，土层2的活化度则在开垦1 a内迅速降低而后一直保持平稳；而络合度的上述年限分别为6 a、14 a和2 a.土壤中全铁的相对含量、氧化铁的活化度和络合度的拟合方程都可反推出土壤的开垦年限，可见铁对土壤环境变迁具有一定的指示作用. |
| 英文摘要 |
| The temporal-spatial trends of soil total iron concentration (Fet), free degree (Fed/Fet), activation degree (Feo/Fed) and complex degree (Fep/Fed) of soil iron oxides after reclamation were studied in Sanjiang Plain Wetlands. The result suggests that Fet in the upper tillage layers (0～20 cm) are influenced by reclamation more significantly than that in the lower ones (20～100 cm), and so does the early ages (0～1 years) than the late ages (1～25 years). Fet is negatively correlated with organic matter extremely significantly (R=-0.62), while that with total phosphorus and pH are not significant. Fet of soil layer Ⅰ (0～10 cm) increases obviously during the first 7 years after reclamation, and tends to become stable after 13 years, while those ages of soil layer Ⅱ (10～20 cm) are 8 years and 15 years respectively. Soil layer Ⅰ shows shorter responding time and better regularity than layer Ⅱ. Fed/Fet increases rapidly after reclamation, decreases later and then increases again. Feo/Fed indicates exponential decrease with the reclamation ages as well as Fep/Fed. Feo/Fed of layer Ⅰ decreases radically during the first 4 years after reclamation and tends to become stable after 13 years, while that of layer Ⅱ decreases dramatically within the first year and keeps stable henceforth. The counterparts of Fep/Fed are 6 years, 14 years, and 2 years respectively. With the fitted experimental equations of Fet, Feo/Fed, and Fep/Fed, the ages of reclamation can be deduced reversely, which indicates the implication of iron on the shifts of soil environment. |
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