Abstract
In the revegetation technique that uses forest topsoil, topsoil is spread over bare land, leading to the germination of buried seeds, thereby creating a pioneer plant community. This revegetation method is known as useful one for preventing erosion and conserving the biodiversity of artificial banked slopes in Japan. This study examined a spraying method using forest topsoil on an artificial cut slope in Tochigi Prefecture, Japan. Topsoil containing 35.4 buried viable seeds/L was collected from a forest by hand to a depth of approximately 5 cm and used to revegetate a cut slope oriented in a SW direction and inclined 66°. The soil was mixed with growth base material in 10, 20, or 30% proportions and used in different areas. After three years, many species emerged at each site, and the coverage ratio was approximately 50% at all of the study sites. This suggests that revegetation will occur when forest soil is mixed in a ratio as low as 10%. Coverage is increased by using topsoil ratios of 20 or 30%. Nevertheless, the results were inferior to past studies of artificial banked slopes. Moreover, in the study, there was few species dispersed from the surrounding vegetation and grew in the slope. The method must be improved in these respects. We also compared the understory vegetation at the site where the topsoil was collected three years after collecting, with that before the topsoil was collected. The emerging species, emergence frequency, and degree of cover of each species were measured. The number of emerging species and total degree of cover increased after collection. This suggests that collecting topsoil to a depth of approximately 5 cm manually does not affect the forest understory vegetation.
