| 三峡库区消落区周期性干湿交替环境对土壤磷释放的影响 |
| 摘要点击 3360 全文点击 1400 投稿时间：2007-04-23 修订日期：2007-08-20 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 三峡库区 消落区 磷释放 淹水 落干 |
| 英文关键词 Three Gorges Reservoir water-fluctuation-zone phosphorous release inundate drain |
|
| 中文摘要 |
| 以三峡库区消落区典型江段万州断面为试验基地，以释磷能力较强的紫色土为对象，根据三峡水库消落带的“干湿交替”空间和时间特征，进行万州断面土壤磷释放的实验室模拟试验，分析了周期性“淹水-落干”干湿交替对土壤磷释放的影响.研究发现，在“淹水-落干”干湿交替条件下各形态磷在水土界面释放的活性为：Ca2-P, Fe-P>Ca8-P, Al-P>O-P>Ca10-P;T-P在每次淹没时释放量递增，从第1次的15.4 mg·kg-1，到第3次26.5 mg·kg-1；磷在持续淹水状态下释放的主要动力为Ca2-P在水相的溶解和还原状态下Fe-P的释放，其中Ca2-P活性最高，由淹水初期的14 mg·kg-1降至5 mg·kg-1左右；而干湿交替条件下P的释放主要是氧化-还原条件变换下Fe-P的形态转换.淹水并不会使O-P释放，但可以使O-P活化，使其在落干氧化时转化为Fe-P，在下一次淹水时释放.研究发现每次淹水时土壤的有效磷水平都略有增加，每次落干时较上次落干时有效磷水平降低. |
| 英文摘要 |
| The water-fluctuation-zone (WFZ) of reservoir and big river had special environmental characteristics that were a joint of aquicolous and terrestrial ecological system.According to the WFZ's alternately waterlogged and drained environment, the control experiment for phosphorous release with purple alluvial soil of the water-fluctuation-zone (WFZ) at the Three Gorges Reservoir were carried out. Research was focused on the characteristics of phosphorous release from soil in the WFZ in periodic inundating-draining environment. Results showed that the release of T-P increased after each inundating process, from 15.4 mg·kg-1 at first time to 26.5 mg·kg-1 at third time. The activity of each phosphorous fraction at the water-soil interface in alternately inundating-draining conditions followed the sequence of Ca2-P, Fe-P>Ca8-P, Al-P>O-P>Ca10-P. The main impetus of phosphorous release at continuing inundating condition was the solubilization of Ca2-P and the transformation of Fe-P at alternately oxidizing-deoxidizing conditions; and the main impetus of phosphorous release at alternately inundating-draining conditions was the latter. In addition, inundation could not make O-P release from the soil, but it activated O-P which transformed to Fe-P when drained and Fe-P could be released when inundated again. The activeness of Ca2-P was highest among all kinds of phosphorous, and its concentration is from 14 mg·kg-1 at beginning of inundated process to 5 mg·kg-1 at end of inundated process. The results showed there was an increase of activated O-P after each waterlogged period, and a decrease after each drained period. |
