Evaluation of two soil conditioners for limiting post-fire erosion as part of a soil conservation strategy

Soil conservation is a major concern for catchments affected by forest fires. The lack of vegetation cover and the development of soil water repellency increase the risk of topsoil erosion. This paper evaluates two soil conditioners (a wetting agent and a polyvinyl acetate) for limiting overland flow and erosion in inter-rill areas. Unburned and burned soil samples were treated with one or both soil conditioners. The effects of these treatments on run-off, water retention, erosion and plant growth were assessed using laboratory rainfall simulations. Polyvinyl acetate had little impact on water retention but was effective in reducing soil loss. The surfactant had little impact on water run-off or soil loss but substantially improved water retention and plant biomass production. Application of soil conditioners on post-fire areas could be a valuable technique in a soil conservation strategy. To maximize their benefits, soil conditioners could be applied with seeding using hydroseeding techniques and be limited to particular areas, such as paths and roadsides. Laboratory results indicate that field testing should also be carried out.