Effects Of Fertilization On Plant Community Structure And Soil Organic Matter In Qilian Mountain Wetland

Wetland is an ecosystem that locates between aquatic and terrestrial ecosystem. There are unique soil, vegetation, hydrology and biological characteristics in that independent ecosystem. Wetland plays an important and irreplaceable role in maintaining ecological balance and regional biodiversity. Plateau wetland is one kind of the richest biodiversity areas in the world. In China, plateau wetlands are mainly distributed in Qinghai Province and Tibet of Qinghai-Tibet Plateau. They are representative and unique in our country and even the world. Their rich resources and huge environmental effects make them become significant biological habitats. In recent years, however, global warming leads to ice melting, river drying up and lake shrinking; wetland gradually has showed a shrinked trend. In addition, human factors such as industrial production and overgrazing have worsened the ecological environment of wetland areas. Therefore, weland ecological environment protection and sustainable development has drawn increased concern from the academic.This experiment area is a high latitude cold wetland where located in Qilian County of Haibei Tibetan Autonomous Prefecture of Qinghai Province(99° 9′ E,38° 25′ N). In this area, the average altitude about 4000 m, the sun’s radiation is strong, and the climate is very harsh. Meanwhile, this area has appeared the phenomenon of wetland degradation. We mostly focus on the research that under nine fertilizer levels, different fertilizer levels had different effects on plant productivity and plant diversity between late July and early August(i.e., the peak period of plant growth)in 2013 and 2014. Then, the content of soil organic matter was determined by potassium dichromate volumetric method, the soil p H(from June to September in 2014)was determined by soil acid hygrometer. Finally, the main data results were compared and analysed by one-way ANOVA methods.The main results were summarized as follows:(1)The plant species in this area mainly Kobresia and Carex, including Kobresia humilis, Carex microglochin, Blysmus sinocompressus, Kobresia tibetica, Carex kansuensis and Poa pratensis, etc.(2)The impacts of fertilization on the plant coverage and aboveground biomass are particularly obvious. Overall, the total trend is compost area(nitrogen and phosphours mixed fertilizer area)> nitrogen fertilizer area > phosphours fertilizer area > control area(no fertilization), and the high-dose area > middle-dose area > low-dose area > control area; the plant height of the main species in 2014 were generally higher than 2013 that under the same fertilization.(3)Generally, aboveground biomass starts to accumulate in early June; during mid-July and early August, the plants achieve rapid growth; till mid-August, the growth of the plants is slow and beginning to stabilize.(4)The richness and Shannon-Weiner index in 2014 is higher than in 2013, and the fertilization area is higher than the control area, and the maximum value is in low-dose area of phosphours fertilizer.(5)The soil organic matter content of this area is very high, and fertilizer area is higher than control area, 0-10 cm soil layer is higher than 10-20 cm, the year of 2014 is higher than 2013. And the compost area is higher than nitrogen fertilizer area and phosphours fertilizer area under the soil layer of 0-10 cm.(6)The soil p H is basically between 6.0 and 7.0, suitable for the growth of most plants. In conclusion, above results can provide some reference for further research about vegetation growth of the high latitude cold wetland ecosystem.