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Doug Warnock: Grazing management after fire

Columnst Doug Warnock writes about pasture and grazing management.

By Doug Warnock

Greener Pastures

Published on November 7, 2018 4:21PM

Doug Warnock

Doug Warnock

When to resume grazing and how to manage grazing following a rangeland or pasture fire are key decisions in fostering the land’s recovery. Maurice Robinette of the Lazy R Ranch near Cheney, Wash., is facing these decisions after a wildfire during the summer of 2018, which burned about 100 acres of the 1,000-acre ranch. Maurice and daughter, Beth, produce grass-finished beef and sell direct to consumers.

While the affected land was 10 percent of the ranch, it wasn’t producing 10 percent of the forage. The area burned was rocky soil with a partial cover of pine trees. However, any loss reduces production and needs to be dealt with.

Robinette said they will watch closely to see how the forage plants in the burned area respond next spring. They plan to establish monitoring sites in each of the three paddocks of the burned area and will use them to gauge the viability of the more preferred grass species. Post-fire management decisions should be based on achieving high vigor of the preferred forage species, according to Tip Hudson, Washington State University Regional Rangeland & Livestock Specialist.

Hudson says, “Post-fire goals must prioritize soil conservation and consider water quality. Soil conservation will always include re-establishment and promotion of grasses, the plant type most necessary for holding down soil.” He offers a series of questions to help in assessing the extent of damage and potential plant recovery.

“Did the burned site have a healthy community of perennial grasses before the fire?” If yes, natural regeneration often occurs in this case. If the plant crowns were not severely damaged, the plants can recover quite quickly. If “black holes” show in the plants’ crown area, recovery may result from seed in the soil. However, re-seeding may be necessary if there wasn’t a healthy plant community present before the fire.

“Was the fire hot enough to create hydrophobic soil conditions where soil aggregates have been “welded” together and will prevent water infiltration?” If yes, the site has potential to erode, especially on steeper slopes, and aggressive erosion control may be needed.

“Were invasive broadleaf weeds or annual grasses abundant before the fire?” If yes, they will likely expand the first spring after the fire. Cheat-grass infested areas require special attention because it has a positive feedback loop in which fire creates conditions particularly conducive to cheat-grass germination in the fall immediately after the fire. In the spring these seedlings have a head start on the desirable perennials and take advantage of the nutrient flush often generated by the fire. This contributes to fuel conditions ideal for another fire. Special attention may be needed to address this situation. Advice is available from your extension educators or range management advisors.

If possible, Hudson suggests deferring grazing on burned pastures until after July 1 the first year after the fire. He also recommends reducing the stocking rate on the burned area. When moving animals between paddocks, key on the preferred plant species. Make sure those plants are not overgrazed and have adequate recovery before the animals return. Hudson proposes changing the timing of grazing each year and letting a paddock go to seed one year in every three. Graze after seed shatter.

The key to post-fire grazing success is to have defined goals, a good plan and to monitor what happens. Adapt the management according to what the monitoring reveals.

Doug Warnock, retired from Washington State University Extension, lives on a ranch in the Touchet River Valley where he writes about and teaches grazing management. He can be contacted at dwarnockgreenerpastures@gmail.com.


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