Abstract:In order to determine the effects of red soil aggregate in different particle-size (<0.25, 0.25~0.5, 0.5~1, 1~2, 2~5 mm) on splash erosion, a simulated rainfall experiment (75 mm/h rain rate and 45 min rain time) was conducted. Aggregate breakdown, splash rates change, net splashed particles and splash spatial distribution were chosen to analyze the splash regulation. The results showed that: (1)2~5 mm aggregate breakdown rate was as high as 96.06%, while <2 mm was less than 50.00%. The index of breakdown rate significantly decreased with the aggregate size increasing. (2)The splash rates of <0.25 mm aggregate skyrocketed at first, and soon collapsed to 0.08 g/min. This phenomenon, in this period, might attributed to soil crust, which was developed rapidly and completely; The splash rates of 0.25~0.5 mm aggregate, which could be clearly observed to become muddy after 18 min rainfall, also skyrocketed at first, but then decreased slowly. The splash rates of 0.5~5 mm aggregate kept a long time increase and also decreased slowly after 36~42 min. (3)There were the same trends for the quantity of total splashed particles, in upslope and downslope area, net splashed particles among different size of aggregate. Splash erosion quantity within 0.25~0.5 mm was the maximum, and then gradually reduced with the particle size increasing. (4)Almost all of splashed aggregates spread in the scope of 60 cm, and the mean weight distance (MWS) of small aggregate was larger than those of the bigger one. This study provided a new approach to reveal the rainfall splash erosion mechanism of red soil, which had great significant for perfection of the physical progress model of rainfall erosion.