Right around the middle of August this year, a lot of folks in Montana were having a hard time remembering what a blue Montana 'Big Sky' looked like. Then a lot of those same folks began to worry about the productivity of land. They can even be beneficial. Even the fire retardants used to fight wildfires can help soil.
Fire retardants are mostly fertilizer-like materials.
The nitrogen and phosphorus in these chemicals may help speed regrowth, though they can also threaten water quality when there is low uptake of these nutrients by plants and the increased runoff after a fire. It's hard to say what exactly the fire has done to your soil, because there are many variables, from the prefire and postfire conditions to the amount of fuel, fire intensity, and the season. A fire will convert a great deal of nitrogen, sulfur and phosphorus to gaseous forms, which are lost from a site. In wildfires, the degree of soil heating will not be uniform across a site. Highest soil temperatures occur where fuel loads are located.