Soil water and nutrients of vegetation communities under different restoration types on the hilly-gullied Loess Plateau

The characteristics of soil water and nutrients in the existent vegetation communities are the very important references for intervening and regulating vegetation restoration.Based on the field survey in Wuqi on the hilly-gullied Loess Plateau,the variation of soil water and nutrients under different vegetation restoration types were analyzed by Canonical Variate Analysis.It was showed that the natural restoration community without disturbance had higher soil water content,organic matter,extractable nitrogen,total phosphorus and exchangeable potassium;communities with long-term(nearly 20 years and more than 20 years) planted trees and planted grasses had lower soil water content and exchangeable phosphorus;natural vegetation communities without management,along with croplands and 4 years old Hippophae rhamnoides community experienced higher exchangeable phosphorus and soil water content,but lower organic matter,(total) nitrogen,extractable nitrogen,total phosphorus and exchangeable potassium.The soil water content of these communities,ranging from the wither moisture to 50% of field water holding capacity,was in severe deficient state;the soil nutrients are also in the lower level for vegetation to develop well.Planted vegetation,especially more than 20 years old planted trees and planted grasses consumed much more soil water than vegetation in natural restoration,and the soil water content in 200500cm soil layers was almost near to wilting point.The results suggested that natural restoration without disturbance could be the better measure for vegetation restoration in the study sites.