Post-fire soil erosion mitigation: a review of the last research and techniques developed in Portugal
Post-fire soil erosion risk assessment is not exempt of uncertainties. In many parts of the world post-fire soil erosion can have devastating effects over forest ecosystems, infrastructures and human life. However, in the Mediterranean countries, it has been defined as “low” and it was attributed to...
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Veröffentlicht in: | Cuadernos de investigación geográfica 2014-01, Vol.40 (2), p.403-428 |
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Sprache: | eng |
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Zusammenfassung: | Post-fire soil erosion risk assessment is not exempt of uncertainties. In many parts of the world post-fire soil erosion can have devastating effects over forest ecosystems, infrastructures and human life. However, in the Mediterranean countries, it has been defined as “low” and it was attributed to a long history of intense land use. This review paper integrates the last research assessing post-fire runoff and soil erosion as well as mitigation techniques focussing inPortugal. In the case of north-centralPortugal, recent research assessing wildfire and ground preparation effects leads to the conclusion that post-fire soil losses was as high as 5-10 Mg ha-1yr-1, while ground preparations soil losses doubled these figures. Since those values are higher than the estimates for tolerable soil losses, further considerations must be taken in order to guarantee a sustainable land use. The advantages of post-fire soil erosion control with straw mulching are well known worldwide. Recently, other treatments were assessed in recently burnt eucalypt and pine plantations in Portugal: 1) the eucalypt chopped bark mulch; 2) the slash logging mulch (unchopped twigs, stems and leaves); 3) the hydromulch, a mixture of water, organic fibres, seeds, nutrients and a surfactant with good performance in cut slopes rehabilitation; and 4) the polyacrylamides (PAM), a chemical agent with good performance in agricultural soil erosion control and high potential due to its low application rate. The more effective treatments were those increasing the ground cover, one of the most important key factors for soil erosion. For this reason, the eucalypt chopped bark mulch and the hydromulch reduced the runoff in 50% and the soil erosion in 80-90%, while the PAM did not achieved the required reduction effect. In areas where the ground cover was high (due to the presence of a needle carpet) the slash logging mulch was not effective since soil erosion was already low in the untreated areas. |
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ISSN: | 0211-6820 1697-9540 |
DOI: | 10.18172/cig.2519 |