This time of year, the ranchers in our valley set
fire to their empty irrigation ditches and pastures. The fires clear-away last year’s dead grasses
and weeds and provide something of an empty slate for the new season. According to a recent Natural Resources and
Conservation Service study published on their Montana website, burning fields
has the short-term benefit of “invigorating” the soils. Burning the dead vegetation provides a small
burst of nitrogen availability. Burning
may also be effective in clearing sagebrush and certain shallow-rooting and
invasive weeds and grasses. Some insects
(considered pests in terms of agriculture) may be reduced.
In the long-term, however, the study reveals a net
reduction in soil health if burning is used to clear fields year after
year. Overall, nitrogen levels in the
soil are reduced. Microbes beneficial
for converting decaying matter into plant nutrients decline to lower levels.
Moderation—as always—seems the best answer.
Inspired by the burning I witnessed as I drove
around our valley this week, I set fire to a single (and long-dead) rabbitbrush
in my yard yesterday. Before I touched fire
to the bush, it stood waist high. After
only five minutes engulfed in a brilliant and wind-swayed pyramid of flame, the
bush was reduced to a stark black and mostly abstract patch in my native
yard. Today I Have posted a picture of a
healthy rabbitbrush and the result of my burning.
--Mitchell Hegman
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