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Riechers, G.H.; Beyers, J.L.; Robichaud, P.R.; Jennings, K.; Kreutz, E.; Moll, J. 2008.
Effects of Three Mulch Treatments on Initial Postfire Erosion in North-Central Arizona. Session C.
USDA Forest Service Gen. Tech. Rep. PSW-GTR-189. 107-113.
Keywords: mulch
Links:
PDF [290 KB]
Abstract:
Mulching after wildfires is a common treatment designed to protect bare ground from
raindrop impact and reduce subsequent erosion. We tested the effectiveness of three mulching
methods on the Indian Fire near Prescott, Arizona, USA. The first method felled all fire-killed
trees, chipped the logs and limbs, and spread the chips across the hillslope with a mobile selffeeding
chipper. The second treatment spread compressed, tackified straw pellets that expand
when wetted and release a soil flocculant. The third treatment was rice straw applied at
4.5 Mg ha-1 (2 tons ac-1).
Each treatment was applied to a small catchment with a silt fence
sediment trap at the mouth. Sediment yield from an untreated (control) catchment was also
measured. The treatments were tested by three erosion-causing summer rain events. The
chipping treatment and the pellets reduced sediment yield by 80 to 100 percent compared to
the control in the first two storms. In the third event, a multi-day storm followed by an intense
thunderstorm, the pellets and straw reduced sediment yield 42 and 81 percent, respectively.
The effectiveness of the chip treatment could not be completely assessed because of partial
failure of the sediment fence. Vegetation cover was low on all sites; ground cover from pellets
decreased more than did straw or chips by mid-October, probably accounting for the lower
effectiveness in reducing erosion compared to straw.
Moscow FSL publication no. 2008n
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