Mulching and seeding treatments for post-fire soil stabilisation in NW Spain: Short-term effects and effectiveness

Abstract

The implementation of post-fire stabilisation techniques in forests ecosystems located in the NW of Spain is required since high severity wildfires are common and the risk of erosion is high due to pronounced terrain relief in combination with abundant precipitation; however, there is limited quantitative information on the relative effectiveness of these techniques. The effectiveness of two stabilisation techniques, seeding and mulching, in reducing soil erosion was evaluated as well as their effects on soil quality. The study was performed on a hillslope area located in Laza (NW of Spain) affected by a high severity wildfire in September 2010. Four treatments were established: unburnt control soil, burnt control soil, burnt soil with rye seeding and burnt soil with straw mulch. For the different soil treatments, the sediments production as well as different physical, chemical and microbiological soil properties were measured over a four month period. The results showed that initially the wildfire induced important changes in most properties analyzed and that these effects persisted after 4months. The data also indicated that both stabilisation treatments had no effects on the soil properties analyzed but reduced significantly the sediments yield compared to that of the control burnt soil. The mean efficiency of seeding and mulching treatments in preventing soil erosion was 34–42% and 73–94%, respectively, showing that, in the short-term (4months), mulching was the most effective treatment for reducing post-fire erosion.