Runoff and sediment yield process on sand-covered loess slopes under simulated runoff conditions were studied through simulating wind-water complex erosion based on the controlled scouring experiments. This study set up three water flow rates (5

10

and 15 L/min) and five sand-covered thicknesses (0

5

15

25 and 35 mm).The results showed that the runoff yield time on the sand-covered slope was extended

and it extended with the increasing of sand-covered thickness. Under different water flow rate

the runoff yield time on sand-covered slopes (5

15

25

35 mm) were 1.29～1.46 times

1.66～2.5 times

2.5～3.76 times and 3.76～4.72 times

respectively

than those on the loss slope. Compared to the loess slope

sediment yield contribution rate was greater than runoff contribution rate on the sand-covered slope. Under the same water flow rate

the total amount of runoff on sand-covered slope was 1.05～1.8 times of that on the loess slope

and the total amount of sediment yield was 1.6～7.5 times. Under different water flow rates

the increase-rate of runoff rate on the sand-covered slope was significantly higher than that on the loess slope within 0～5 min

and in the later 25 min of runoff

increase-rates of runoff rate on both two kinds of slopes were basically coincident. In the whole runoff

the fluctuation of runoff rate on sand-covered slope was significantly higher than that on loess slope. With the increasing of water flow rate

the initial sediment yield strength on sand-covered slope significantly increased. However

in the same water flow rate

the initial sediment yield strength did not increased significantly with the increasing of sand-covered thickness. Under different water flow rates and different sand-covered thicknesses

the sediment yield strength firstly increased dramatically

then decreased

and then gradually reached a steady state

and the fluctuation of sediment yield strength on the sand-covered slope was significantly higher than that on the loess slope. The results indicated that the sand-covered slope destroyed the stability of the water flow

and aggravated soil erosion at a certain extent.