ASSESSMENT OF SEDIMENT YIELD BY SPLASH EROSION ON A SEMIARID SOIL WITH VARYING CRYPTOGAM COVER

Cryptogams are a group of non-vascular plants including algae, lichens, mosses, liverworts and fungi which form crusts when associated with surface soils. A series of experiments were undertaken to investigate the role of cryptogams in erosion processes on a red earth soil in semi-arid eastern Australia. Under 20 min of simulated rainfall at an intensity of 45 mm h-1, the presence of cryptogams significantly reduced both the total amount of material that was eroded by splash and the rate of removal from a semi-arid red earth soil. As cryptogam cover increased, there was an exponential decline in total splash erosion and an increase in the proportion of coarse material in the sediment. The results indicate that, under natural rainfall conditions, there is a continual transfer of fine material and adsorbed nutrients away from areas of low cryptogam cover. The application of these results to the management of soils with cryptogamic surfaces is briefly discussed.