三峡库区消落带沉积物与土壤磷形态及分配特征研究

Phosphorus Forms and Distribution Characteristics in Sediments and Soils of Water-Level-Fluctuatig Zones of Three Gorges Reservoir Area

应用沉积物中磷形态的标准测试程序（SMT）对三峡库区典型消落带表层新生沉积物及土壤中形态磷进行分级测定,并探讨形态磷之间及其与有效磷和样品理化性质（有机质和铁）之间的相关性。结果表明：消落带沉积物及土壤中总磷（TP）含量分别在435.1-970.0,152.8-1 022.7mg/kg之间,均值分别为（713.6±124.3）,（547.5±169.7）mg/kg,沉积物中TP含量远高于土壤,显示了新生沉积物吸附磷的能力高于土壤。无机磷（IP）是沉积物及土壤中磷的主要形态,分别占TP的78.2%,74.2%;有机磷（OP）只占较小的比例。沉积物及土壤中钙磷（Ca—P）是IP的主要赋存形态,Ca—P/IP均值为73.6%,74.1%,而铁/铝磷（Fe/Al—P）占IP比重仅为26.4%,25.9%。沉积物及土壤中有效磷（Olsen—P）含量分别在4.43-45.50,2.88-41.84mg/kg之间,其中分别有29.6%,11.1%的样品超过土壤磷素淋失的Olsen—P临界突变点（25mg/kg）。回归分析表明,沉积物中Fe/Al—P和OP是Olsen—P的主要贡献者,而Ca—P对Olsen—P的贡献很小;土壤中仅Fe/Al—P对Olsen—P有较大贡献。相关分析表明,有机质与OP呈极显著正相关,说明有机质的输入可促进OP的累积;TP、Fe/Al—P、Ca—P与无定形态铁（Feo—Fep）、有机络合态铁（Fep）呈显著正相关,表明Feo—Fep和Fep可促进沉积物及土壤的固磷作用。

The contents of different phosphorus forms in surface sediments anct soils of water-level-fluctuaing zone of Three Gorges Reservoir were measured through the use of the standard measurement and test （SMT）, and correlation coefficients among phosphorus forms, available phosphorus and physicochemical characteristics （organic matter and Fe） of samples, were also analyzed. The main results were as follows： TP contents in sediments and soils of water-level-fluctuating zone varied from 435.1 mg/kg to 970.0 mg/kg, and from 152.8 mg/kg to 1 022.7 mg/kg, respectively, and the mean contents were （713.6±124.3） mg/kg and （547.5±169.7） mg/kg, respectively. Additionally, the average content of TP in sediments was much larger than that in soils, indicating that phosphorus adsorption capacity of fresh sediments was higher than that of soils. IP was the main form of phosphorus, which oceupied 78.2% and 74.2% of TP in sediments and soils, respectively. However, the ratios of OP/TP were much smaller in sediments and soils. Ca-P was the domination form of IP, occupying 73.6% and 74.1% of IP, while the ratios of Fe/AI-P to IP were 26.4% and 25.9% in sediments and soils, respectively. Olsen-P contents varied from 4.43 mg/kg to 45.50 mg/ kg, and from 2.88 mg/kg to 41.84 mg/kg in sediments and soils, and 29.6% and 11.1% of samples were beyond the break point of phosphorus leaching （25 mg/kg） in sediments and soils, respectively. Regression analysis showed that Fe/A1-P and OP contributed greatly to Olsen-P in sediments, while the contribution of Ca-P to Olsen-P was very small. Only Fe/Al-P had a great contribution to Olsen-P in soils. There were significant positively correlations between organic matter and OP, suggesting that the accumulation of OP was associated with the input of organic matter. What＇s more, TP, Fe/Al-P and Ca-P had positive correlations with Feo-Fep and Fep, indicating that Feo-Fep and Fep had a role in promoting phosphorus adsorption in sediments and soils.