Abstract: Taking non irrigated flatlands in Hefei outskirts as experiment observation areas, yellow brown soil as selected soil type, and < 3癮s ground slope,the time of runoff development,runoff quantities,and silt carrying capacity under different rainfall intensity were observed on the non irrigated farmlands with different kinds of crops such as grain, oil, cotton and vegetables,and with different coverage for continuous 3 years.Based on the observation, water and soil samples were collected and analyzed.The results showed that the loss way of the surface soil and nutrients in non irrigated flatlands was obviously different from that on the sloping fields and on the upland.Over 98% of available N, P, and K nutrient loss were run off by chemical erosion.Physical erosion was the main way of the surface soil and organic matter loss, and 96.14% of total organic loss was caused by physical erosion.