六叉河小流域不同景观结构中径流磷形态差异分析

选取巢湖六叉河小流域,研究了流域内不同类型景观降雨产流过程中径流磷素的形态差异.结果表明,旱地径流中总磷、溶解性总磷、颗粒态总磷、总活性磷、颗粒态活性磷的浓度最高,水稻田次之,河道中最低.颗粒态磷是旱地和水稻田磷索输出的主要形态,颗粒态活性磷占总活性磷的80%以上;而河道径流中各种磷形态浓度值均较低,总磷浓度均值在0.4mg·L-1以下,磷素输出以溶解态磷为主.磷素由旱地经过水稻田向河道传输过程中,颗粒物浓度显著下降,河流中颗粒态磷浓度降低至50%左右,活性组分浓度显著降低.由水塘、沟渠等组成的多水塘系统不仅降低了磷素输出的总量,而且对活性磷有较强的削减作用,在非点源流域控制及水源地水质保护方面有重要意义.

Phosphorus speciation in the runoff from different land uses in the Liuchahe watershed by Chaohu Lake

Runoff from the Liuchahe watershed, a typical agricultural watershed characteristic by many Multipond Systems in Southeast China, was evaluated for phosphorus speciation by land use. The runoff from farmland, paddy rice fields and the Liuchahe River was selected for study. Total phosphorus (TP), total dissolved phosphorus (TDP), total particulate phosphorus (TPP), total reactive phosphorus (TRP), particulate reactive phosphorus (PRP) and dissolved reactive phosphorus (DRP) were monitored in the runoff. TP was the highest in the runoff from farmland, while it was the lowest in the river, as was other forms of phosphorus except DRP. Particulate phosphorus was the main form of phosphorus in the farmland runoff, with TPP/TP ratios from 80% to 90%. During the transportation from farmland to paddy rice field and riverway, both the concentration and forms of phosphorus were changed, and particulate phosphorus decreased significantly. As a sink structure of the watershed, the river had better water quality, with TP under 0.4 mg·L-1 and the main component was dissolved phosphorus. The results suggest that the Multipond System in the Liuchahe watershed decreases not only total phosphorus, but also the reactive component, which is important in controlling nonpoint source pollution and protecting the water quality of Chaohu Lake.