Study On The Meadowization Process Of Tundra Soil, Changbai Miountian

The tundra of Changbai Mountain is one of three alpine tundra of China and the changesof the tundra soil on physical and chemical properties will cause the variation of tundralandscape. In recent years, because of herbaceous plants invading into the tundra, greatchanges have taken place on physical and chemical properties of the tundra soil and the tundrasoil has the trend of meadowization process what also has an important influence on thetundra vegetations. The study of tundra soil has not only the important scientific significance,but also has the important ecological significance to soil and vegetation protection ofChangbai Mountain tundra.With the phenomenon of the Calamagrostis angustifolia represented herbaceous plantcommunities invasion the tundra, the study focuses on tundra soil of Changbai Mountain asthe research object and the western slope of2000-2500m range as the study area. It dividedinto four contrast plots such as the native flora, the mild invasion, the moderate invasion andthe severe invasion area, according to the succession at different stages between theherbaceous plant communities as the representative of Calamagrostis angustifolia and thenative plant community as the representative of Rhododendron aureum. Samples wereselected in each of the plot which was of0.2m×0.2m and selected twelve different altitudeswith repeated samplings. By using the method of laboratory measurement analysis, we havemeasured all the following data including soil organic carbon, total nitrogen, humus, humicacid, fulvic acids, carbon and nitrogen ratio, total iron, ferrous iron, ferric iron, humic acidand fulvic acid ratio. Then the data have been analyzed by the means of statistics, with thepurpose of revealing the law of the tundra soil on physical and chemical properties in differentaltitudes and different invasion degree of plaques, and then this study aims to put forward thephenomenon of tundra soil locally generated meadowization process. The results showed that:First, in the same altitude, the physical and chemical properties of soil have significantdifferences in the different invasion degree of plaques. With the Calamagrostis angustifoliainvasion, the water content of soil elevated in growing season. The organic carbon andnitrogen reduced and the carbon and nitrogen ratio has slightly decreasing trend. Humuscomposed mainly of fulvic acid and humic acid and fulvic acid ratio was about0.5. Total iron,ferrous iron and ferric iron content increased and ferrous iron was more than50%of the totaliron content. They reflect the retention sterile process and gleization process of the soil. Thechanges of properties reflect the characteristics of the meadow soil in different invasionregions and soil properties are the determinant to the soil type. Therefore, the tundra soil has the trend of meadowization process.Second, at different elevations, the soil humus, fulvic acid, humic acid, organic carbon,total nitrogen and total iron nutrient content tended to decrease with increasing altitude in thedifferent invasion degree of plaques. Ferrous iron content did not change significantly butwith increasing altitude ferric iron content significantly reduced. Humic acid and fulvic acidratio and carbon and nitrogen ratio have an upward trend with increasing altitude. With theinvasion of herbaceous plants, the available nitrogen content and the water content increasedin soil that promoted the growth of invasion plants. the types of shrubs vegetation weregradually reduced; however, the types of herbaceous plants were on the contrary. Dominantspecies is significantly different in the different invasion regions and herbaceous plant wasmainly in the severe invasion region, which gradually replaced shrub plant communities.Third, the variance gradually reduced with increasing altitude between the differentinvasions degree of plaques. The changes of tundra soil properties show that climatic andtundra soil conditions of the high altitude inhibit the Calamagrostis angustifolia invasion andthere are no significant changes with increasing elevation. The proportion of different nutrientelements significant changing in the different invasion regions reflects the meadowizationphenomenon of tundra soil, with the invasion of the Calamagrostis angustifolia. Plaquescluster analysis reflects the tundra soil properties quite different in the base of tundra soil andmeadowization phenomenon is significant and wide distribution.