2 typical soil in the Loess Plateau (Loess and Lou soil)

2 different rainfall intensities (45.5 mm/h and 95.5 mm/h) and 2 slope gradients (8.7% and 25.9%) were used to qualify the impact of 3 water quality (deionized

tap and saline water) on runoff and soil erosion in rainfall simulation. The results showed that the runoff rate acted differently between 2 types of soil. Tap water and saline water delayed the time of runoff yielding

but the runoff rate of deionized water grew more slowly than tap water and saline water under Loess. For Lou soil

deionized water always showed the highest runoff rate

while tap water and saline water were similar in ion amount

and did not differ in runoff rate. Water quality influence the runoff indirectly by the formation and development of crust. When precipitation was 45.5 mm

runoff amount significantly decreased with the increasing electrical conductivity

tap and saline rainwater decreased runoff depth by 5.7 mm and 1.7 mm for Loess

and by 7.2 mm and 9.8 mm for Lou soil

compared with deionized rainwater. The sediment yielding rate had significantly difference under different rainwater conditions and it was closely related to the runoff rate. Deionized water had a maximum sediment yield

while tap and saline rainwater decreased runoff depth by 45.9% and 35.8% for Loess

and by 65.6% and 68.3% for Lou. It should be noted that runoff and erosion was significantly affected by the quality of water in simulated rainfall. Deionized water was recommended for rainfall simulation to improve the accuracy and comparability of results.