Study On Utilization Strategy For Mineral Nutrients Of Wetland Plants On Floodplain In The Xilinhe River

Focusing on riparian wetlands in the typical segment of Xilinhe river, this paper studied the utilization for mineral nutrients (mainly N and P) of the dominant wetland plants and its influencing factors. Such related research has not been carried out on the watershed of Xilinhe river, which is a permanent riverine wetlands in semiarid areas. Our study can enrich those kinds of research in this region and provide not only scientific guidance for restoration of degraded wetland ecosystem, also suggestion for protection of wet meadow in the arid and semi-arid area.Based on the field work and experimental cultivation, the nutrient levels, community dynamics, mechanism of nutrient transport, plant adaptability to barren habitat and its interspecific differences in wetland were analyzed. Then the utilization strategies of mineral nutrient of wetland plants were given. The main conclusions are as follows:1. Due to the water saturated habitat, the soil bulk density in wetland is lower than typical steppe.2. The contents of available N and P in wetland community are less than the typical steppe, maintaining the relatively oligotrophic levels, which are also slight differences between the various wetland communities.3. The content of N and P of soil are not dominant factors to determine the biomass dynamics of wetland communities.4. Nutrient Deficiency Symptom were not shown in wetland plants during the nutrient stress experiment for two years, which revealed the wetland plants have great adaptability to nutrient barren habitats. Those wetland plants can also be divided into the independent external environmental nutrient species and dependent external nutrient environmental species.5. N and P could be transported from the aging leaves to the mature leaves in this experiment, but the transferred amount may be depended on the type of plant. It shows that there lies the mechnism of biological cycle in wetland plants. So wetland plants could be cultured in the distilled water for a relative long period.6. Compared with the typical steppe, the contents of N and P in wetland plants are higher, but lower in wetland soil, which reflected the nutrients were mainly stored in the wetland plants, not in soil. So, obtaining the nitrogen from soil may be not the dominant in the wetland.