Effects Of Litter On Seedling Establishment Of Herb Species In Leymus Chinensis Grassland

In order to provide scientific information for successful seedling establishment during the process of restoration of degraded grassland enclosed, a two-year study was conducted from 2009-2010 to determine the effects of litter and seed position on seedling emergence, survival and earlier growth performance of 4 wild herbal species: Agroppyron cristatum, Elymus dahuricus, Bupleurum chinese and Saposhnikovia divaricata to investigate the suitable management of litter in the enclosed Leymus chinensis grassland. Seeds of A. cristatum, E. dahuricus, B. chinense and S. divaricata were sowed to the pots adding different qualities of litter in Saibei Administrative Region, Hebei Provence, and different concentrations of litter extract were added to dishes containing 4 species seed in the laboratory of Hebei University. The results indicated that:1. Seedling emergence of the 4 species was significantly promoted under the coverage of 100 g/m~2-200 g/m~2 of litter. The max germination rates of the seeds within these coverage ranges were 69.58%, 91.46%, 54.58% and 54.58% separately, the max survival rates were 98.76%, 97.69%, 96.44% and 97.37%; biomass, height and leaves number of seedlings were much higher than the control group under the coverage of 200 g/m~2 of litter, it is more conducive to the earlier growth performances of these 4 wild herbal species. Therefore, conserving 100 g/m~2-200 g/m~2 of litter was much more appropriate for plant restoration by seeds in the enclosing management of nature grassland in Saibei area.2. Suitable seed position favored seedling emergence, survival and earlier growth performance. Seedling emergence and survival rates of the 4 species were higher broadcasted under soil, the max germination rates were 85.94%, 98.28%, 56.67% and 53.44% separately, the max survival rate were 95.50%, 96.51%, 98.17% and 98.44%; when it comes to their earlier growth performances, A. cristatum and E. dahuricus grew much better under soil, while B. chinense and S. divaricata under the coverage of litter. In summary, seeds scattering on the litter surface were unwilling to germinate and grow in the enclosed grassland, thus appropriate disturbance in the course of enclosure favor them dispersing into inner soil and growing into adult plant.3. Extractions of litter do affect seedling establishment, both promotion and inhibition can be observed in the experiments. It has no significant effect on seed germination of the 4 species, while it influences the morphology constructions and growth of seedling by affecting radicals and sprouts elongation, which is favorable for A. cristatum and E. dahuricus, but going against the radical elongation of B. chinense and S. divaricata. Different influences differ with species.4. Most effects of litter on seedling establishment were physical and species-specific. Accumulation of lager amount of litter has much more influence than intermediate and small amount, appropriate litter control management can maintain species diversity and protect natural resources in Leymus chinensis grassland.