Study On Water Purification And Competitive Growth Of Different Wetland Plants

At present,agricultural non-point source pollution not only causes eutrophication of rivers and lakes,but also poses a serious threat to ecosystems.It has become a common environmental problem in the world.Therefore,it is necessary to construct an ecological ditch to control agricultural non-point source pollution at the source of the river basin,which can reduce the pollution of nitrogen and phosphorus,reduce the pollution load and improve the environmental quality.In order to realize the effective management of the Chaohu River Basin agricultural non-point source pollution,we studied the removal of nitrogen and phosphorus and other pollutants in the aquatic ecosystem of farmland drainage ditches in plants,and provide a theoretical basis and practical basis for the prevention and control of Chaohu and non-point pollution in Chaohu basin.We planted different aquatic plants in farmland ecological ditch in Xisong villiage,Tongyang town,Chaohu basin,analysied the reduction effect of nitrogen and phosphorus of different plants,the distribution of nitrogen,phosphorus and organic matter content in ditch sediments,variation of plant community diversity in ecological ditches.In order to determine the interception and removal efficiency of different root type wetland plants,the growth status of two root type plants under different sewage concentration,concentration and planting density was carried out indoors.The results showed that:(1)Apium graveolens,Acorus tatarinowii and Vallisneria natans Hara have better removal effect on nitrogen and phosphorus in farmland ditch,the total nitrogen removal rate was 56.18%-74.58%,the ammonium nitrogen removal rate was 36.23%-59.33%,the removal efficiency of nitrate nitrogen is 34.35%-66.88%,the phosphorus removal rate is 44.38%-76.35%.(2)Sediment environmental quality of Tongyang Town Xi song villiage is good as a whole,N,P all are mild to moderate pollution ditch pollution,organic pollution is more serious;the content of TN and OM were significantly positive correlation(r=0.903,P < 0.01),TP was weakly correlated with OM(r=0.073,P < 0.332).(3)In ecological ditch plant community after two years of evolution,community types and species number increased,plant community types and structure gradually from simple to complex,different segments within ditches and Shannon Wiener index,Simpson index,evenness and richness changed greatly.(4)We have set up 5 different planting densities,and explored the changes of growth of Acorus calamus and windmill roots under different planting densities.The result shows that the increase of planting density had no significant effect on the growth of Acorus calamus and the length of the root,but with the increase of planting density,the surface area of the root of Acorus calamus and the root of the wind decreased,and the plant height and biomass decreased.(5)low concentration of eutrophic water on Shichangpu and windmill grass roots have a significant role in promoting the growth of high concentrations inhibited the increased as the concentration of two kinds of plant root length,root surface area,biomass decreased.The root surface area,plant height and biomass were lower than those of Acorus calamus in low and medium concentrations,and the root number was higher than that of Acorus calamus in three concentrations.