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Evaluating the effectiveness of agricultural mulches for reducing post-wildfire wind erosion
Robichaud, P.R.; Jennewein, J.; Sharratt, B.S.; Lewis, S.A.; Brown, R.E. 2017.
Evaluating the effectiveness of agricultural mulches for reducing post-wildfire wind erosion.
Aeolian Research 27:13-21.
Keywords: Tackifier, Friction velocity, Sediment transport, Rice straw, Wheat straw
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Abstract:
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 s1). 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 m2 at the lowest wind speed which increases to 6258 g m2 at the highest
wind speed. Adding wheat or chopped wheat mulch significantly reduced sediment loss by an order or
magnitude (698 and 298 g m2, respectively) at the highest wind speed. Adding chopped rice straw
reduced sediment loss by a half to 3573 g m2 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.
Moscow FSL publication no. 2017b
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