The Effects Of Oxbow Lake On The Characteristics Of Grassland Plant Communities In The Gonger Drainage Area

Oxbow Lake is a special lake at the sides of the river in plain or high-plain areas, which plays an important role in the formation of wetlands around this river as well as the changes of ecosystem through the effect of soil moisture around it. The community characteristics and nutrition components of grasslands surrounding the third grade Oxbow Lake of the Gonger River were investigated in this experiment. The results were shown as follows:(1) The height, coverage, density, and the aboveground biomass of community decreased gradually with an increase of the distance from the bank in the unformed areas of the Oxbow Lake. The Values of which in Carex appendiculata formation was high, and in Stipa grandis formation was low. The number of the plants species decreases and then increases with an increase of the distance from the bank, of which in Carex appendiculata formation was high, and in Leymus chinensis formation was low. The height, coverage, density, and the aboveground biomass of community at the sides of river and Gonger Rive were high in the formed areas of the Oxbow Lake, which were decrease far away the sides of river, of which in Stipa grandis formation was low.(2) In the unformed areas of the Oxbow Lake, the content of calcium and crude ash increased with an increase of the distance from the bank, the content of water absorption decreased, then increased;The content of crude fat increased then decreased;The content of crude protein and crude fiber increased first,then decreased and increased again; the content of phosphorus,and nitrogen free extract decreased first,then increased and decreased again. In the formed areas of the Oxbow Lake,the content of nitrogen free extract and water absorption were high while the content of crude protein was low in Carex appendiculata formation; In Sanguisorba officinalis formation,the content of water absorption, calcium, crude ash and nitrogen free extract were high and the content of crude fiber were low; The content of crude fat was high in Calamagrostis epigejos formation and low in Iris lactea formation; The content of phosphorus was high in Potentilla anserina formation, Artemisia tanacetifolia formation and Iris lactea formation ,whereas low in Calamagrostis epigejos formation.