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The transformation of stream power was analyzed under different water discharge amount on loess slope in Hydraulic Research Base of Yellow River Institute of Hydraulic Research. The observation data shows that: the stream powers were increasing gradually with time at the initial stage, and then they got the waved steady state at 10-18min in different water drainage amounts on 20°slope, at this moment, the steady stream power of 10 L/min water drainage amounts was biggest, about 30P, it was 1.8, 1.5, 7, 17 times than the steady stream power of 7.5, 5, 4, 3L/min water drainage amounts; the stream powers got the waved steady state about at 16min in 5L/min water drainage amounts on different grades slope, at this moment, the steady stream power of 20°slope was biggest, about 20P, it was about 1.3 times than the steady stream power of 10°and 30°slope. They had a good relationship of power exponent between stream power and denudation rate, the related coefficient was 0.81, so we can indicate the denudation rate by the stream power.

Pisha Sandstones are widely distributed in the wind-water erosion intersection zone of northwestern China. In this region, serious soil and water loss has caused the riverbed of the lower Yellow River to become higher than the adjacent ground. Fifty-two samples of four types of Pisha Sandstones (purple, white, pink and gray) from different depths (0 m, 2 m and 10 m) were examined in laboratory experiments to gain a better understanding of the relationship between erosion and the loss of Pisha Sandstones as well as the mechanisms of erosion. All of the samples were analyzed using chemical methods, X-ray diffraction and scanning electron microscopy. The mineral and chemical compositions of Pisha Sandstones were found to be very different from those of ordinary soil and varies greatly during the whole erosion process (sampling depth). Wind-water erosion also affected the microstructure between the deep and surface Pisha Sandstones, ultimately causing gravitational erosion and the loss of Pisha Sandstones. Although not all of the observations could be explained, it was apparent that wind erosion, water erosion and gravitational erosion had both direct and indirect effects on the loss of Pisha Sandstones.

The runoff amount, soil erosion amount and infiltration rate were analyzed on different rainfall and different underlying horizon in base of yellow river institute of hydraulic research at 2018. The date shows: the runoff amount of bare slope is 7 times that of grass slope, the runoff amount of heavy rainfall is 2 times that of middle rainfall and is 20 times that of small rainfall; the soil erosion amount of bare slope and arable slope is 100 times that of grass slope; the steady soil erosion amount of small rainfall is 1/4 times that of middle rainfall and is 1/30 times that of heavy rainfall on grass slope; the infiltration rate of bare slope and arable slope is 1/3 times of grass slope; the grass slope infiltration rate is about 0.6mm/min in small rainfall, the middle and heavy rainfall get the steady infiltration rate at experiment continue 30min and 12min.