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  

Characteristics of Phosphorous Release from Soil in Periodic Alternately Waterlogged and Drained Environments at WFZ of the Three Gorges Reservoir

作　　者：马利民[1] 张明[1] 滕衍行[1] 赵建夫[1] 

机构地区：[1]同济大学长江水环境教育部重点实验室

出　　处：《环境科学》2008年第4期1035-1039,共5页Environmental Science

基　　金：国家科技支撑计划项目(2006BAJ08B01);国家“十五”科技攻关重大项目(2003BA808A17);同济大学污染控制与资源化国家重点实验室基金项目

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.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 inundatingdraining 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.

关 键 词：三峡库区 消落区 磷释放 淹水 落干 

分 类 号：X53[环境科学与工程—环境工程]