Soil Seed Banks And Aboveground Vegetation Of Rehabilitated Farmland In Shannxi Province

In this study, typically rehabilitated farmland in wind erosion crisscross region of Shaanxi Wuqi is selected as research subjects in northern Loess Plateau. The study was conducted on the farmland in different years and aspects, through the years were 0 of rehabilitated farmland (agricultural land),2,3,8, 9,12 (this kind of shady and sunny places were selected as the comparative study),20 and 30 years of rehabilitated farmland plots on the ground vegetation and soil seed bank for the field site survey, sampling and laboratory germination experiments on the basic characteristics of the soil seed bank, aboveground vegetation.characteristics and comparative similarity analysis, the preliminary results are showed below:(1) The seed germination of soil seed bank distribution pattern in the study area is not rising with the years of rehabilitated farmland, but at first increased and then decreased peak trend, density changes in 467.0±34.4～4283.0±312.2 grains/m2, which is the highest density of soil seed bank in rehabilitated 8 and 9 years.(2) In the experiment, germinable seed density in 0～5cm soil changes between 367.0±36.0 and 2833.0±224.0 grains/m2; 5～10cm soil layer changes between 100.0±14.9 and 1450.0±104.2 grains/m2. Soil seed bank density of 0-5cm layer is about 2 times than that of 5～10cm.(3) The soil seed bank germination of plants are formed by the majority of dicotyledonous plants, the number of seed germination 1136 grains/m2, while the number of monocot plant seed germination for the 713 grains/m2, only account 38.5% of the total number.(4) Statistics on the ground vegetation in the CPC are 6 families and 15 genera,25 species of plants, mainly are Gramineae plant species (7), Compositae (7 species) and legumes (4 species), Rosaceae (5) are the second one; From the type of plant life, the highest proportion of perennial grasses appeared, followed by half the proportion of shrub plants, the lowest proportion is biennial herbs.The soil seed bank are mainly Artemisia gmelinii, Lespedeza, Stipa grandis, Leymus and other early successional species in rehabilitated farmland. There are both no woody plants in the soil seed bank and abovegroud. Therefore, to speed up the research area vegetation restoration process, it should be properly introduce some later successional species to shorten recovery and succession time. In the revegetation process, planting colonization provenance artificially to promote the vegetation restoration of water erosion of wind erosion crisscross area in the north loess plateau.