Based on the data of individual rainfall

runoff and sediment yield of five runoff plots from 1984 to 2015 in Suining Soil and Water Conservation Experimental Station

68 rain processes were classified into four rainfall patterns. The effects of rainfall patterns on runoff and sediment yield of sloping farmland were analyzed for different slopes. Then the results showed that there were highly significant correlations between runoff depths and rainfall intensities of different periods (p＜0.01). With the slope gradient increasing

the period of rainfall intensity for the greatest correlation coefficient became shorter. The amount of sediment was significantly correlated with the average rainfall intensity during each individual rainfall

and the correlation coefficient was maximum. The fitting curve between runoff depth

the amount of sediment

and rainfall intensity was an increasing function of convex and concave shape

of which interval was between 0.79 and 0.88

and 0.90 and 0.97

respectively. It was indicated that the correlation between sediment yield and rainfall intensity was more affinitive than that between runoff depth and rainfall intensity. With the slope gradient increasing

runoff and soil erosion became greater. At the same slope gradient

the yields of sediment and runoff of rainfall IV (short duration

heavy rainfall) was the biggest

followed by rainfall Ⅲ (moderate duration

moderate intensity)

rainfall II (long duration

moderate intensity)

and rainfall I (long duration

light intensity). Furthermore

the difference between rainfall IV and rainfall I was significant (p＜0.05). When the slope gradient was about 15°

the effects of rainfall pattern were the most obvious. Overall

runoff and sediment yield increased with increasing slope gradient. Rainfall IV was the main pattern of rainfall causing soil erosion. In the future

we should take some measures of soil and water conservation to reduce soil erosion caused by rainfall IV on sloping farmland.