Three hydro-seeding revegetation techniques for soil erosion control on anthropic steep slopes

Erosion control at low-medium radioactive waste disposal sites is an import ant concern. A study was carried out in El Cabril (Cordoba, Spain) on two 4 0 per cent anthropic steep slopes in order to test the effectiveness of hyd ro-seeding techniques for controlling soil erosion. Two groups of 10 m x 3 m plots were established. The treatments tested were: hydro-seeding with th e application of vegetal mulch (VM); hydro-seeding with added humic acids ( HA); hydro-seeding with vegetal mulch and humic acids added (VM+HA); and a control without hydro-seeding or soil amendment (C). Fifteen run-off produc ing rainfall events were recorded during the study period, with intensities ranging between 2 mm h(-1) and 33.6 mm h(-1). All treatments significantly reduced runoff and soil loss (p < 0.05). The VM + HA treatment was the mos t effective, reducing 98.5 per cent of total soil loss. The HA treatment (9 7.1 per cent reduction) was also more effective than the VM treatment (94.8 per cent reduction). A great reduction in runoff and sediment yield was observed in the treated plots during the first stages after hydro-seeding. This result may be attri buted to the combined effect of: (a) the protection against raindrop impact due to the application of straw and mulch to the soil surface, and (b) a g eneral improvement in the soil's structure brought by the organic amendment s. Seven months after hydro-seeding, an increase in the density of the plan t cover could be added to the beneficial effects mentioned above. Copyright (C) 2000 John Wiley & Sons, Ltd.