A Preliminary Study On Soil Seed Bank And Soil Properties In The Subalpine Meadows, The Tibetan Region, Northwestern Yunnan

Located on the border of Yunnan, Tibet and Sichuan provinces, Diqing Tibetans autonomous prefecture is rich in ecotype and the biodiversity. The eco-geographical edge effect is remarkable. There are 456,700 hm2 meadows. Stockbreeding is the most important mode of production in this are. In recent years, with the big increase of livestock, the degeneration of the meadows has been more and more clearly.We studied 5 different managed meadows which share the same environment in Dala Tibetan Village of Shangri-La County. The comparative studies were mainly aim at the composition of plants species, soil seed banks and soil properties. Our intention is to offer some effective data to the comparative studies about different managed lands.The 5 different managed meadows we studied were cultivated meadows, grazing pastures, forage meadows, deserted-hill boscages and barley terra. The results were as follows.(1) The character of soil seed banksThere were 67 species of plants that belong to 20 families had been found in 5 different managed meadows. The majority of them were dicotyledonous of angiosperm, including 55 species of seed plants that belong to 18 families. Of which, 12 species belong to 2 families of monocotyledon. Asteraceae Compositae and Gramineae Poaceae have taken an important part in the plants we studied. The mainly life forms of those plants were Perennial herbaceous plants, there was a little while Biannual herbaceous plants or Annual herbaceous plants. And no shrubs were found.We also found that the density of seed banks which had been collected in spring is much bigger than seed banks which had been collected in autumn. And the density of seed bank in cultivated meadows is much bigger than the other 4 meadows. On the side, beside the barley terra, the density of seed bank in 0-5cm is bigger than 5-10cm. Furthermore, it is irrelated between the vegetation above the ground and the soil seed banks.(2) Soil propertiesThe soil nutrients of grazing pastures were on the high side, and the roots biomass of grazing pastures were also higher than others, then we can find that soil nutrients could affect on productivity of plants.For the average soil moisture content, forage meadows>grazing pastures>cultivated meadows> barley terra>deserted-hill boscages. It is resulted that culture could make the soil dry, and what's more, the soil moisture content of deserted-hill boscages was low because of the altitude of the hill.Being man-made culture, there was a little while roots in barley terra, which made it with the biggest soil bulk density. The soil bulk density of the other 4 kinds of meadows were less than or equal to 1.0 g/cm3 for the roots of the soil. Cultivated meadows had been plotted once before, so the soil bulk density of this kind of grassland was less than barley terra and more than other 3 kinds of meadows. It is said that the roots biomass could affect the soil bulk density.In general, the meadows deteriorate extremely and seriously. But traditional meadows management- forage meadows were benefited to maintain the accumulation of biomass, improve the soil fertility, and protect biodiversity.