Study on soil and water loss affected by landuse/cover under different rainfall types plays a significant role in soil erosion cont rol and vegetation restoration

which can give scientific guidance to the practice. Based on 14 years of measurements in the experimental hydrologic plots

different rainfall patterns were classified. Precipita-tion amount

duration and maximum 30 min intensity were selected as the comprehensive index to divide the local rainfall events into three different patterns. Generally

pattern 1 is the aggregation of those with medium intensi-ties

durations and amounts. Pattern 2 is the aggregation of rainfall events with such features as high intensities and short durations. Pattern 3 is the aggregation of those with low intensities and long durations. Accordingly

runoff and erosion features of five landuse types governed by these three rainfall patterns

as well as their features in different years

are all stressed. The main results are shown as follows. Firstly

from the static point of view

the lands characterized by the mean runoff coefficient s and mean erosion moduli are in the order of seabuckthorn > natural grass > Chinese Pine > alfalfa > wheat . The reason why alfalfa land has severe runoff and erosion may be re-lated to its growing characteristics and human disturbance. Secondly

runoff and erosion under rainfall pattern 2 hold the most serious position

followed by pattern 1 and pattern 3. This means that rainfall events with high in- tensities and shorter durations play dominant roles in causing soil and water loss in the semiarid area. Lastly

perennial plants such as seabuckthorn and Chinese pine show a very clear trend that runoff coefficients and erosion modulus decrease with time. Soil and water loss is serious in the first several years after plantation

then decreases obviously and get s stable at a lower level. Therefore

more attention should be paid to the different stages of vege2 tation succession.