(a) To be eligible for the production of foundation seed, a field must not have grown or been seeded to the same species during the previous five years.

(b) To be eligible for the production of certified seed a field must not have grown or been seeded to another strain or variety of deertongue during the previous three years, except with foundation or certified seed of the same variety.

(c) No manure or other contaminating amendments shall be applied during the established and productive life of the stand.