The apparent explanation for this condition is the fact that the summer fallow becomes infected with wind-blown spores, while in a stubble crop the wind-blown spores, as well as those originating from the previous crop, are buried in plowing.
"If clean seed or properly treated seed had been used by all farmers we should never have had a smut problem.

High per cents.

of smut indicate either soil infection or imperfect treatment.

The principle of the chemical treatment is to use a poison which will kill the superficial spores of the smut and not materially injure the germinating power of the seed.

The hot-water treatment is only recommended when one of the chemical 'steeps' is not effective.
"Certain cultural practices are beneficial in reducing the amount of smut in all cases, while the value of others depends to some extent upon the source of the smut spores.