Research On Variation Characteristics Of Nitrogen During The Restoration Processes Of The Typical Riparian Wetlands

In this research, the Yellow River wetland was selected as the research area. Fieldinvestigation and laboratory simulation were comprehensively applied intoinvestigating the riparian wetland soil characteristics of different communities,variation features of soil nitrogen and distribution characteristics of nitrogen indifferent communities after recovery. The research results are as follows:(1)Soil of study area is alkaline, mainly mealy silt and sand. Soil texture is lightand their fountainhead are wash and deluvial deposit，and soil nutrition content is low.Hydrological environment of wetlands was changed by Xiaolangdi reservoir, with lownutrient content, and also caused the distribution of soil nutrients in different plantcommunities. Content of soil OM was significant positive correlation with TN andammonium nitrogen content. Higher values of pH caused lower content of soil OM,TN, NH4+-N. The number of bacteria was the max one. Only actinomycetes hadsignificant positive correlation with OM, NO3--N and bacteria. TN, OM, NH4+-N andNO3--N had different origins.(2) The mainly composition of N in organic nitrogen, and N’s characteristics ofhorizontal distribution was obviously. Content of TN in surface soil were larger thanbelow. OM content was lower than the before. OM and TN was significant positivecorrelation in level0.01.(3) Influenced by Yellow River hydrology, bacterium concentrated on0-5cm innature riparian wetlands, the concentration of actinomyces decrease with soil depthincrease. Soil microorganism content of the main vegetation community in researcharea is: bacterium (84.48%～88.04%)> actinomyces (11.92%～15.43%)> fungi(0.03%～0.09%). Microbial population increased was mainly due to the increase ofplant root secretions, which increased gonging by with time.(4) After1years of recovery, it formed aquatic plant communities withPhragmites communis Trin, Typha angustifolia Linn and Polygonum hydropiper. Thebiodiversity was rich. Biomass of the three above was913g/m2,357g/m2,880g/m2.Phragmites communis Trin had a higher uptake on nitrogen. The N content of leaves was higher than the other organs, which could indicate that vegetation was importantstorage of nitrogen.(5)Reserves nitrogen content of three communities were13.11g/m2、4.57g/m2and11.90g/m2, Show the purification ability of Phragmites communis Trin on N.Uptake capacity of the ground part was significantly higher than that of undergroundpart. Uptake capacity of NO3--N and NH4+-N was differences. Mainly nitrogen ofbotany was organic nitrogen, and inorganic nitrogen content was small.(6) Soil nitrogen content of Phragmites communis Trin was the lowest of the threecommunities, while nitrogen content of the plant was the highest. The nitrogen contentof Phragmites communis Trin was the highest of the three communities. At the layer of10cm (20cm especially)-concentrated area of the roots, Nitrogen content ofPhragmites communis Trin reduced obviously.Roots of Phragmites communis Trin absorbed and transferred nitrogen to leaves,and then concentrated in leaves. The purifying capacity of Phragmites communis Trinwas the best in the Yellow River riparian wetland.