中文摘要：

选取了落干期澎溪河流域6个消落区点位,分析了消落区土壤磷形态分布特征,并探讨了各形态磷之间的相关性.结果表明,（1）采用SMT法测定了消落区土壤总磷、无机磷和有机磷含量,其总磷TP含量均值为575.29 mg·kg^-1,有机磷OP含量均值为91.23 mg·kg^-1.（2）采用Hedley法分析了消落区土壤磷的5种赋存形态,其中WA-Pi、PA-Pi、Fe/Al-Pi等3种易迁移的无机磷形态之和占可提取Pi的11.61%,且低于岸边土壤;WA-Po、PA-Po两种生物可利用性较高的有机磷形态含量之和占可提取Po的22.28%,而中活性有机磷Fe/Al-Po占可提取Po的66.30%,且消落区土壤各形态Po含量均低于岸边土壤,又以Fe/Al-Po含量差异最大.（3）消落区土壤TP与活性较强的WA-Pt、PA-Pt呈显著相关,表明消落区土壤活性磷含量主要受TP影响;各形态磷之间不具有显著相关性,表明不同形态磷的来源可能不同;消落区土壤Fe/Al-Pt与土壤有机质OM呈显著相关,表明土壤有机质的含量可能影响铁铝结合态磷含量.在淹水条件下,消落区土壤磷组分的释放对上覆水体的潜在影响不容忽视.

英文摘要：

The concentrations of phosphorus fractions in the soils of the water-level-fluctuating zone（ WLFZ） of Pengxi River in the Three Gorges Reservoir were analyzed. The total phosphorus（ TP）,inorganic phosphorus（ IP）,and organic phosphorus（ OP） were studied using the standard measurement and test（ SMT） procedure. The average TP concentration was 575. 29 mg·kg^-1and the average OP concentration was 91. 23 mg·kg^-1in the soils of WLFZ. The fractions of phosphorus were analyzed by the Hedley method.In the soils of WLFZ,the relative abundance of WA-Pi（ weakly adsorbed inorganic phosphorus）,PA-Pi（ potential active inorganic phosphorus）,and Fe/Al-Pi（ Fe/Al-bound inorganic phosphorus） accounted for 11. 61% of the extractable Pi,lower than that in the unflooded bankside soils. The relative abundance of WA-Po（ weakly adsorbed organic phosphorus） and PA-Po（ potential active organic phosphorus） accounted for 22. 28% of the extractable Poand the Fe/Al-Po（ Fe/Al-bound organic phosphorus） accounted for 66. 30%.In addition,the Pocontent of the soils of WLFZ was lower than that of the unflooded bankside soils and the difference in the Fe/Al-Po content in both soil types was the highest. WA-Ptand PA-Ptwere significantly correlated with TP in the soils of WLFZ,which indicated that the active phosphorus content was mainly affected by TP. There was no statistical correlation between different fractions of phosphorus,suggesting different sources of phosphorus fractions. The Fe/Al-Ptcontent was significantly correlated with OM,implying that the OM content may affect the Fe/Al-Ptcontent. Therefore,under flood conditions,the potential impacts of phosphorus in the soils of WLFZ on overlying water should not be neglected.