摘要
农业区域的面源污染是引起湖泊富营养化的主要原因之一。多水塘系统是用于灌溉的中国古代发明,它由许多沟塘组成,星罗棋布地分布在农田中。我们通过在巢湖六叉河小流域的长期试验研究,发现用多水塘系统能够有效地控制面源污染。多水塘系统能够显著地降低径流速度,具有贮存暴雨径流,减少水、悬浮物和磷元素输出的强大功能。在面积为691.6hm^2的六叉河小流域,多水塘系统平均每年可截留固体悬浮物和磷分别达14.38×10~6kg和7016kg。其中,灌溉是磷循环和去除的有效途径。采用多水塘系统使宝贵的养分资源循环利用,能减少湖泊的磷氮负荷,是控制面源污染的可持续方法。
Diffuse pollution from agricultural land is one of the main causes for lake eutro-phication. Multipond systems, an ancient invention in China, are composed of many tiny ponds and ditches, scattered in agricultural fields. After a long period of research in an experimental watershed in Liuchahe, it was found that multippnd systems constitute diffuse pollution control. They have a large capacity for water storage and serve to control the export of water, suspended matter, and phosphorus. Multipond systems significantly reduce runoff velocity. Sediments and phosphorus retained in the Liuchahe watershed were 14.38. 106 and 7016 kg yr-1 respectively (area 691.6 ha). Irrigation provides an effective way to recycle and remove phosphorus. The use of multipond systems is a sustainable way to recycle valuable nutrients and reduce their discharge and thus pollution of downstream lakes.
