巢湖典型小流域表土磷的空间分异特征及影响因素分析

研究了巢湖北部的烔炀河-岐阳河小流域土壤、富磷地质区岩石风化碎屑及烔炀河沉积物等表土物质中总磷（TP）含量,以及NaOH提取态磷（NaOH-P）、HCl提取态磷（HCl-P）、有机磷（OP）等形态组成特征,探讨了富磷地质区岩源性磷及人为污染对表土磷空间分异的影响。结果表明,土壤中TP平均含量为436.8mg·kg-1,其形态组成以OP和NaOH-P为主,分别占到TP含量的41.6%和32.0%,HCl-P平均百分含量为11.8%;富磷地质区岩石风化碎屑中TP平均含量4539.5mg·kg-1,其形态组成以HCl-P为主,NaOH-P、HCl-P、OP分别占到TP含量的0.5%、74.9%、3.5%;烔炀河沉积物中TP平均含量为683.0mg·kg-1,NaOH-P、HCl-P、OP分别占到TP含量的45.0%、20.6%、24.9%。空间上,HCl-P含量在流域上游的富磷地质区最高;NaOH-P含量在流域上游地区较低,而在流域中游-下游地区逐渐增加。烔炀河-岐阳河小流域表土中总磷含量与形态组成空间分异受到富磷地质区岩源性磷及人为污染的共同影响,其中岩源性磷对流域上游地区影响较大,而在中下游地区受到生活污水及化肥施用等人类活动的影响程度较大。

Spatial Variation of Phosphorus in Topsoil of a Typical Watershed in Chaohu Lake Basin and the Main Controlling Factors Analysis

Concentrations of total phosphorus（TP） and the chemical species in the phosphorite-bearing rock detritus, soil and sediment sampled from Tongyang-Qiyang watershed were determined. The spatial variations in concentrations and chemical species of TP in the topsoils and the main controlling factors were discussed in this paper. Average concentration of TP in the soil was 436.8 mg. kg-1 and mainly presents in the species of OP and NaOH-P, accounting for 41.6% and 32.0% of TP concentration, respectively. The average percentage of HCl-P in the soil was 11.8%. Concentration of TP was 4 539.5 mg· kg-1 on average in the phosphorite-bearing rocks detritus, which was dominated by the specie of HCl-P. NaOH-P, HCl-P and OP account for 0.5%, 74.9% and 3.5% of TP concentration in the phosphorite-bearing rocks detritus. Concentration of TP was 683.0 mg· kg-1 in the sediments from Tongyang River on average, and the percentages of NaOH-P, HCl-P and OP were 45.0%, 20.6% and 24.9%, respectively. Spatially, higher values of HCl-P occured in the northern areas of Tongyang-Qiyang watershed, where phosphorite-bearing rocks were distributed. NaOH was with lower values in the northern areas and increasing values in the middie-lower reaches of the watershed, which varied differently from HC1-P in spatiality. Spatial variations of TP and the chemical species in the topsoils of Tongyang-Qiyang watershed were regulated by the origins from the phosphorite-bearing rocks and anthropogenic pollution. Phosphorus originated from the phosphorite-bearing rocks prevailed in the northern area of the watershed, and that from anthropogenic pollution, such as fertilizer usage and sewage discharge, was dominant in the middle-lower reaches of the watershed.