To understand the characteristics of erosive aggregate loss in tropical and subtropical zones

a combination experiment of two discharge flow (5 L/min and 7.5 L/min) and four simulated rainfall intensities (0 mm/h

60 mm/h

90 mm/h

120 mm/h) was conducted. The variation characteristics of aggregates

such as mean weight diameter (MWD)

geometric mean diameter (GMD)

fractal dimension (D)

mean weight soil specific area (MWSSA)

were analyzed. The results showed that: the aggregates of ＜0.05 mm occupied 19％～58％ of the total sediment during the early phase of the event

and the tendency declined first then stabilized with rainfall duration. The content of ＞0.25 mm aggregates in erosive sediment was highest

and the tendency increased first and stabilized later

with the rainfall duration

. When the discharge flow increased from 5 L/min to 7.5 L/min under the same rainfall intensity

MWD and GMD of aggregates increased

while D and MWSSA decreased. MWD and GMD of aggregates in the sediments without rainfall were lower than that in the rainfall; however

D and MWSSA of aggregates in the sediments without rainfall were higher than those with rainfall. Under the condition of the same rainfall

MWD and GMD increased as rainfall intensity increased

while D and MWSSA decreased.