空心菜对入星云湖河水的净化及其生物产出分析

Water Purification and Productivity of Ipomoea aquatica Grown on River Water Flowing to Xingyun Lake in Yunnan Province

为充分开发利用入星云湖河水的N、P等营养资源,降低其富营养化水平,改善和保护星云湖生态系统,于2010—2013年采用微区试验与大区试验相结合、静态试验与动态试验相结合的方法,研究了漂浮空心菜(Ipomoea aquatica)对入星云湖河水净化及其生物产出的规律。结果表明:漂浮空心菜对入湖河水具有较好的水质净化效应,静态条件下空心菜对入湖河水全N、水溶性P的去除率高达90%以上,动态条件下则达50%左右,空心菜吸收入湖河水N、P、K的量分别平均为348.4、50.9、530.4 kg·hm-2·a-1,且其绝大部分被空心菜的茎叶吸收(占93.0%,为864.5 kg·hm-2·a-1)。空心菜对入湖河水的净化量,以水溶性N计平均为27 321 m3·hm-2·a-1,以水溶性P计平均为67 569 m3·hm-2·a-1;空心菜的生长主要依赖入湖河水中N、P等营养物质(两者呈正相关),通过茎叶大量吸收并同化入湖河水中的N、P等养分后,空心菜获得了较高的茎叶生物产出量(占90.9%,鲜重量平均为112 032.0 kg·hm-2·a-1)。利用入星云湖河水漂浮种植空心菜,产生了明显的生态效益和经济效益。

Purification of eutrophic water by aquatic plants is an ecological practice widely used in recent years. To make use of N and P resources in river water flowing to Xingyun Lake in Yunnan Province, to reduce the lake eutrophication and to protect the lake ecosystem, micro-plot trials, macro-plot trials, static trials and dynamic trials were carried out from 2010 to 2013. The purification effectiveness and productivity of Ipomoea aquatica grown in floating-beds on river water were studied. Results showed that Ipomoea aquatica had a high purification effectiveness. Under static conditions, removal rates of total N and water-soluble P by Ipomoea aquatica from river water were greater than 90%, while the rates were about 50% under dynamic conditions. Average amount of N, P, and K absorption by Ipomoea aquatica in river water was 348.4 kg·hm-2·a-1, 50.9 kg·hm-2·a-1and 530.4 kg·hm-2·a-1, respectively. Most of these nutrients(93.0%)were accumulated in the stems and leaves of Ipomoea aquatica. Average amount of river water purified by Ipomoea aquatica calculated by water-soluble N and water-soluble P was 27 321 m3·hm-2·a-1and 67 569 m3·hm-2·a-1, respectively. The growth of Ipomoea aquatica was positively correlated with N and P concentrations in the river water, and average fresh weight of stems and leaves was up to 112 032.0 kg·hm-2·a-1. Therefore,it is obvious that growing Ipomoea aquatica in floating-bed on river water not only improves water quality in Xingyun Lake, but also provides significaant economic benefits.