[Fractal characteristics of daily discharge in different scales watersheds].

Based on the fractal theory and the long-term daily discharge records, this paper analyzed the fractal characteristics of daily discharge in mid-scale watershed (Wushui watershed) and small-scale watersheds (Zhenfu and Shuangxi watersheds). Under the same time scales and different threshold values of daily runoff, the fractal characteristics of daily discharge in the watersheds of different spatial scales and of same spatial scales were evident, and existed self-similarity. With the increase of the threshold values of daily runoff, the fractal dimensions of the daily discharge of different space-scale watersheds decreased gradually.

[Soil infiltration capacity under different vegetations in southern Ningxia Loess hilly region].

A new apparatus for measuring the run off-on-out under simulated rainfall conditions was used to study the soil infiltration capacity under different rainfall intensities and vegetations in loess hilly region of southern Ningxia, with the relationships between soil water-stable aggregate content and soil stable infiltration rate under different vegetations analyzed. The results showed that the regression equations between rainfall duration and soil infiltration rate under different vegetations all followed y = a + be(-cx), with R2 ranged from 0.9678 to 0.