[Eco-restoration of abandoned farmland in the Loess Plateau].

The vegetation on abandoned farmland was succeeded from Agriophyllum arenarium community to Lespedeza davurica community under cutting conditions. More plant species was recruited at the initial stage of restoration. The new plant species established earlier were annual Agriophyllum arenarium and perennial Pennisetum flaccidum which could be the dominant species or sub-dominant species. The perennial Artemisia capillaris established in early-middle stage could be the sub-dominant species, and leguminous plants appeared in late-middle stage could only be the associated species. The aboveground biomass of annual species reduced by 8.8% annually, while the perennial species increased with the similar rate. The aboveground biomass of leguminous species increased continuously. As the restoration proceeded, more underground biomass was distributed in upper soil layer. In 1-7 years of restoration of abandoned land, the clay and silt in 0-30 cm soil profile reduced, while grit increased, but the inverse trend occurred after 7 years. The water content in 0-100 cm soil profile increased continuously, especially during middle stage. Total and available nitrogen in 0-100 cm soil profile reduced in early stage, but increased in late stage. Total and available phosphorus and organic carbon in soil profile reduced continuously under cutting conditions. For the restoration of abandoned farmland to the current stable community, it would take 8-9 years for dominant population, 9-11 years for vegetative community and 11-12 years for soil system.