A Research On Soil Seed Bank Of Different Age Artificial Forests (Caragana Intermedia) In Desert Steppe

In this paper, the ground vegetation survey and soil seed bank germination experiments used on ground vegetation species diversity and soil seed bank characteristics of desert grassland in different forest age caragana forest, elaborated species composition, diversity characteristics, seed density, seed bank spatial distribution pattern on the ground vegetation and soil seed bank, and also study the coupling relationship between soil seed bank and above ground vegetation in the area. In arid and semi-arid desert grassland, water is limit plant growth and seed germination of soil seed bank. It’s plant growth determine factors, it’s controling the progress and direction of plants recovery, so that this paper is use water control experiment, explained the effect of soil seed bank in different water gradient, specially explained species composition and seed bank quantity in different water gradient. In order to provide theoretical guidance for management regress steppe in arid and semi desert. The main results obtained in the following conclusions:1.50kinds plants in the study area, soil seed bank have33kinds of plants, ground vegetation number are35kinds. Which species appeared18kinds in soil seed bank and the ground vegetation. Only apeared17species in the ground vegetation expect for soil seed bank, species that only appear in the soil seed bank are15species.2. There were significant differences in ground vegetation species diversity of forest age caragana forest. With forest age increase, diversity indices were increased after decreased, and there are significant differences in the P<0.05level.16a Caragana forest species diversity is good, uniformity index is high than other age forest, so proposed study area Caragana are stubbled in about20years.3. Soil seed bank number have a significant increased in Caragana plantation. The mean density of soil seed bank is11248.75m-2in desert steppe, soil seed bank density of semi-fixed sand dunes is661.25m-2, after planting is17times than before planting. And different forest age caragana soil seed banks mainly in the0-2cm, accounting for about80%of0-10cm.4. The whole study area Caragana forest soil seed bank and ground vegetation species composition has a low similarity, but species composition similarity is significantly increased between soil seed bank and ground vegetation in the planting Caragana forest. Species composition similarity between ground vegetation and soil seed banks close to natural succession grass.5. Study area Caragana forest soil seed bank and aboveground vegetation density and the number of plants between then there is no significant correlation. On the P<0.05level, linear functions, logarithmic functions, polynomial functions, power functions, exponential functions can not be used to express the correlation between the density of the soil seed bank and aboveground vegetation in the study area between several plants.6. Different daily rainfall to stimulate seed bank species composition and seed germination number were significant differences. With the increase of daily rainfall, the number of species in the soil seed bank increased after decline, but the total number of germinated seeds in the soil seed bank is increas. Different annual rainfall to stimulate study area seed bank species composition was not significant differences, while to stimulate seed germination number is a fluctuation type. Needed water is different for their own seed germination, so in order to manage study area regress desert grassland, restoration study area ground vegetation, proposed study area should consider to using different gradients water to stimulate seed germination in seed bank.7. Planting Caragana forest has significant ecological restoration effects in arid and semi-arid desert steppe. In regress desert grassland, ground vegetation species and number are significantly increased in planting Caragana forest than not planting area. Planting Caragana forest to species diversity of regress desert grassland soil seed bank has a positive ecological effects. Species diversity in soil seed bank of natural succession grassland are below than other age Caragana forest.