Effects And Responses Of Common Emerged Plants To Nitrogen And Phosphorus Characters In Three Deifferent Sediments In Lake Erhai

This study deals with current state of ecological restoration in the Lake-sided Zone of Erhai Lake, makes a comprehensive survey for the distribution of typical emergent plant and sediments by field investigation and pot experiment, investigates the influence of three kinds of sediments---Sandiness sediment, Fishpond sludge and Bay sludge on the growth of Zizania caduciflora, Typha orientalis and Acorus calamus, and discusses the impact of harvesting the three kinds of emergent plants on N and P removing of three types of sediments and phosphorous forms in sediment. The main conclusions are as follows.(1) Through analyzing the reaction and influence of three kinds of emergent plant on N and P in sediments, it has found the most suitable conditions of sediments for different emergent plants. The water retention and nutriment interception capacity of Sandiness sediment is low comparing with Fishpond sludge and Bay sludge. The three kinds of emergent plants grow faster with the former two kinds of sediments. Acorus calamus and Zizania caduciflora are most suitable for growing in Fishpond sludge as well as Typha orientalis for Bay sludge, which show that different emergent plants need for different sediments. Moreover, this study provides theoretical basis for cultivating emergent plants.(2) Harvesting emergent plants has a significant improvement for the lake-sided water quality. The influence of harvesting the three kinds of emergent plants on TN removing is not obvious in Sandiness sediment with less nutrition(P>0.05). But the results is opposite in Fishpond sludge and Bay sludge which have better effect with more nutritio, Acorus calamus in removing the fishpond sludge sweet TN the largest contribution to the content of up to65.5%. The three kinds of emergent plants in Fishpond sludge and Bay sludge have a higher strain-away rate of TP than in Sandiness sediment, Fishpond sludge silt conditions Acorus calamus on the removal rate of TP is75.5%, and hence be easier to be absorbed by plants. Therefore, adopting timely and reasonable harvesting way can remove eutrophication in lakes effectively.(3) Researching on all kinds of phosphorus forms can be adopted to evaluate phosphorus content used by aquatic plants in sediments. For the sedimentss in Erhai Lake, the content of Fe-P ranks only second to Ca-P, the other few. The impact of emergent plants on the content of Fe-P and NaOH-P is not significant(P>0.05), emergent plants makes the sediment Ca-P content of the largest reduction (about66%), the second is Fe-P (about61%), and other forms of the influence of phosphorus is smaller,Think that only a tiny fraction of the erhai lake Fe-P and Ca-P can be translated into the plants were using P, according to the proportion of each form P, estimate the erhai lake sediment about50%of P cannot be quite water plants use, this also is P be restrictive nutrition elements of one reason.Thereby, it can design collocation planting for those two factors, thus provides certain theoretical basis for removing the content of N, P and organic matter in lakes purposively., which has positive significance to understand eutrophication in Erhai Lake and implement comprehensive control.