SEASONAL INFLUENCE OF REED (PHRAGMITES AUSTRALIS) AND LOTUS (NELUMBO NUCIFERA) ON URBAN WETLAND OF YI RIVER

Our research objective was to compare the eutrophication inhibition of reeds and lotuses on water body of wetland system of Yi River, evaluate ecological benefits of the two wetland systems, and reveal the response mechanism of water environmental factors, which not only has ecological theoretical significance, but also has extensive practical application value in the management and evaluation of wetland water ecosystem of Yi River.Three research sample plots were set up in Yimeng Lake of Yi River: reed water area, lotus water area and natural water area.In August (summer), October (autumn), December (winter) of 2018 and February 2019 (spring), subsurface water samples were collected and analyzed by laboratory detection for pH, chromaticity, total hardness, dissolved oxygen, BOD, COD, ammonia nitrogen, total nitrogen, total phosphorus, nitrate and chlorophyll a. Research results were as follows: 1) pH appeared as that of lotus water area > natural water area > reed water area, chromaticity appeared as that of natural water area > reed water area > lotus water area.Total hardness appeared as that of natural water area > lotus water area > reed water area, dissolved oxygen appeared as reed water area > lotus water area > natural water area.BOD appeared as that of lotus water area > natural water area > reed water area, COD appeared as that of lotus water area > natural water area > reed water area.Ammonia nitrogen appeared as that of reed water area > lotus water area > natural water area, total nitrogen appeared as that of natural water area > lotus water area > reed water area, total phosphorus appeared as that of reed water area > natural water area > lotus water area, nitrate appeared as that of natural water area > lotus water area > reed water area, and chlorophyll a appeared as that of lotus water area > natural water area > reed water area.2) pH appeared as that of winter > spring > summer > autumn, chromaticity appeared as that of summer > autumn > winter > spring.Total hardness appeared as that of winter > autumn > spring > summer, dissolved oxygen appeared as that of spring > summer > winter > autumn.BOD appeared as that of spring > winter > autumn > summer, COD appeared as that of autumn > summer > winter > spring.Ammonia nitrogen appeared as that of winter > spring > autumn > summer, total nitrogen appeared as that of spring > summer > autumn > winter, total phosphorus appeared as that of winter > spring > autumn > summer, nitrate appeared as that of spring > summer > autumn > winter, and chlorophyll a appeared as that of autumn > summer > spring > winter.Our research conclusion is that reed can effectively increase dissolved oxygen and greatly reduce BOD, COD, total nitrogen, nitrate and chlorophyll a. Lotus can effectively increase pH, BOD, COD, chlorophyll a, and greatly reduce total phosphorus.It is recommended to increase reed community area and try to expand lotus community in the water areas with severe phosphorus load.