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Evaluating the effectiveness of agricultural mulches for reducing post-fire wind erosion

Author(s): Peter R. Robichaud, Jyoti Jennewein, B.S. Sharratt, Sarah A. Lewis, Robert E. Brown
Year Published: 2017
Description:

Post-wildfire soil erosion can be caused by water or aeolian processes, yet most erosion research has focused on predominantly water-driven erosion. This study investigates the effectiveness of three agricultural mulches, with and without a tackifier, on aeolian sediment transport processes. A wind tunnel was used to simulate post-wildfire wind erosion at three wind speeds (6, 11 and 18 m s−1). Shallow trays containing soil collected after a wildfire were treated with chopped rice, wheat or chopped wheat mulch; mulch treatments were also compounded with liquid treatments, tackifier to water ratios of 1:6, 1:3 and water. The mulch treatments were generally easily moved at all wind speeds with cover reductions greater than 90% at the highest wind speed. As expected, sediment loss was greatest for the bare soil treatment, ranging from 6.5 g m−2 at the lowest wind speed which increases to 6258 g m−2 at the highest wind speed. Adding wheat or chopped wheat mulch significantly reduced sediment loss by an order or magnitude (698 and 298 g m−2, respectively) at the highest wind speed. Adding chopped rice straw reduced sediment loss by a half to 3573 g m−2 at the highest wind speed, but the effect was not significant due to mobilization of the mulch. The most effective sediment loss mitigation was achieved with liquid tackifier treatments when applied to bare soil and when compounded with various mulch treatments, particularly at the highest wind speed. These results may aid management decisions when mitigating aeolian sediment transport after wildfires.

Topic(s): Fire Effects, Ecological - Second Order, Soils, Post-fire Management
Ecosystem(s): None
Document Type: Book or Chapter or Journal Article
NRFSN number: 16578
Record updated: Feb 2, 2018