The production cycle of cereal crops and grasses in many areas of the United States includes burning fields of post-harvest residue such as wheat stubble. Like smoke from forest fires, smoke produced by agricultural burning can have harmful effects on public health.
The U.S. Forest Service and the Washington State Department of Ecology conducted a study to determine the effects different ignition tactics had on the smoke produced by agricultural burning of wheat residue.
They found that smoke plumes produced from burning wheat residue using head fires contained more soot than plumes produced using backing fires.
Soot particles are black aerosols composed primarily of elemental carbon. The World Health Organization reports that soot particles may have significantly greater negative health impacts than other particle types found in smoke and air pollution since these particles can act as a carrier for toxic combustion-derived chemicals.
From being a prescribed fire contractor it’s a productivity issue. More burning time in prescription less time on site per acre.
You can back fire through large units of continuous fine fuels but it takes forever. You can go in and use multiple lines of backing fire simultaneously backing until the wind shifts. More work on internal control lines (we used foam lines). Great technique when you can’t put up large soot or fly ash columns.