Research On Vegetation Restoration In The Hilly And Gully Regions Of The Loess Plateau

The hilly and gully region of the loess plateau is an area suffering serious soil and water loss. There is much difficulty in vegetation restoration and eco-environment deterioration, which restrict the socioeconomic sustainable development severely. So vegetation restoration research not only can illuminate the key restraint factor of vegetation recover, but can give the theoretic supports to the vegetation eco-system's reconstruction. Through field survey on the vegetation characteristics of different restoration phase and soil environment in forestry (Yanan), forestry steppe (Ansai) and typical steppe area (Wuqi), and with the methods of spatial replacing temporal, systematical research was carried out on the vegetation succession, species diversity, and the change of soil moisture and soil nutrient during different restoration period of vegetation. Based on these researches, regionalization and appraisement of vegetation restoration was also analyzed. The main results as follows:1. Adopt the fuzzy aggregation analysis to reveal forestry steppe area (Ansai, sunny slope) plant community succession series: Artemisia scoparia community-Leymus scalinus community-Stipa bungeana community-Artemisia gmelini community. Species diversity change in stage of plant community succession are as follows:natural plant communities have relatively high index of abundance , species diversity and evenness especially in the third succession stage; The species diversity and abundance index of artificial bush communities was higher than that of artificial grass communities,but evenness index is lower than that of grass communities;similarly,The species diversity and abundance index of natural plant communities was higher than that of artificial plant communities,at the same time,it has lower abundance index than that of artificial plant communities.2. In different plant area (Ansai,Yanan and Wuqi), the soil water content for different restoration year(s) has following discipline: as a whole, the soil water content below 60cm depth gradually decreases with the increasing time since land was left to regenerate; the deep soil water content tend towards stability progressively with increasing time .The soil water content under different types of vegetation: the soil water content under grassland is relatively high and that under woodland is relatively low. Results for soil water content for different vegetation restoration measures suggest soil water content under natural restoration is higher than that under manual restoration. The soil water content evaluations for different...