三峡库区澎溪河流域不同高程消落带土壤磷形态特征

研究了三峡库区澎溪河流域落干期不同高程消落带土壤不同磷形态分布特征，并分析了各形态磷与土壤理化性质之间的相关性。结果表明，澎溪河流域消落带土壤TP含量均值为599.00 mg/kg，消落带土壤TP、IP含量均沿高程逐渐下降。消落带土壤活性磷（Ac-P）含量明显低于180 m的岸边土壤，155，145 m消落带土壤Ac-P含量低于165 m消落带土壤，与140 m沉积物中Ac-P含量相近，表明频繁的干湿交替会加剧消落带Ac-P的流失。消落带土壤TP、IP和Ca-P均与pH值表现出显著的负相关关系，表明pH对土壤磷形态的含量有着重要影响；OM与Or-P表现出极显著的正相关性，表明有机质的输入在一定程度上会影响Or-P的含量。

Characterizations of phosphorus fractions in the soil at different altitudes of water-level-fluctuation zone,Three Gorges Reservoir

The concentrations of different phosphorus fractions in the soils obtained in the Water-Level-Fluctuation Zone (WLFZ) of the Pengxi River Basin, Three Gorges Reservoir were analyzed. In addition, correlations between these concentrations and different physical-chemical characteristics of the soil samples were also analyzed. The results indicate that the average concentration of total phosphorus (TP) is 599.00 mg/kg. And both the TP and inorganic phosphorus(IP) concentrations gradually decrease with the decrease of altitude. The concentrations of active phosphorous(Ac-P) in the soils of the WLFZ significantly less than those of the riverside at the altitude of 180 m, Ac-P concentrations at the elevation of 155 m, 145 m are close to those of the sediment at the elevation of 140 m but lower than the concentration detected in the samples obtained at the altitude of 165 m. The distribution of Ac-P concentrations at different altitudes indicate that the frequent dry-wet alternations result in the loss of Ac-P in the soils. There is a significent negative correlation between the pH and the TP, IP and Ca-P, meaning the increase in pH result in the decrease in TP, IP and Ca-P, and the organic matter concentration is positively correlated with the organic phosphate concentration, indicating that the input of organic matter affected the concentration of organic phosphate.