Growth And Reproduction Of Forage And Dynamic Of Seed Bank Utilized By Different Ways

On the Leymus chinensis grassland of the Bashang plateau, Zhangjiakou in Hebei province. Mowing meadow and grazing meadow which were symmetrical vegetation and almost consistent terrain were chosen to set up research sites. On base of community, the plant reproductive strategy, soil seed bank and seed rain were systematically researched, from June to October in 2005. The characteristics of reproduction and vegetative succession on level of community were analyzed. The study contents and research methods were as follows:1. At the beginning of August 2005, on mowing meadow and grazing meadow, the methods of vegetative surveys were used, investigated the vegetation of Bashang plateau. The different of vegetative composing between mowing and grazing meadow were evaluated.2. In the every phenological period, through random sampling, the reproductive strategy of community of leymus chinensis was investigated.3. Setting up fixed quadrates, through the method of continually Statistic, determined the mature seeds in the fixed quadrates. Observed the quantities and composed of the seeds rain.4. The time and spatial dynamic of the seed bank were surveyed in mowing meadow and grazing meadow by using a method of taking samples with an earth core of known volume and emergency in greenhouse.Principal research results were as follows:1. The numbers of plant species recorded in mowing meadow were 28, and there were 32 in grazing meadow. The vegetation of mowing and grazing meadows were dominated by perennial, including Leymus chinensis, Poa annua, Stipa grandis, Artemisia eriopoda, Taraxacum mongolicum and Iris ensata. There were a few of annuals, biennial and subshrubs. Mowing meadow and grazing meadow both were steppa subpratensia, and leymus chinensis was the only dominant species.2. The disturbance degree of mowing to plants was lower than grazing. The interference of grazing could lead to the plants smaller and the rhizome shorter. And the action of grazing could increase the diversity of grassland plants.3. The output of seed rain of the mowing meadow was 13968.6seed/㎡, and the grazing meadow was 1222.6seed/㎡. In the seed rain of mowing meadow gramineae and compositae were absolutely predominant, the percentage was...