(a) Foundation seed for the production of registered seed shall be planted on land on which no birdsfoot trefoil except the same variety and class of certified seed was grown or planted during the five years prior to the one in which the present stand was planted. During the year immediately prior to seeding, the land shall have been in a cultivated crop and the land shall be free from volunteer plants. No manure or other contaminating amendments shall be applied during established and productive life of the stand.

(b) Registered or foundation seed for the production of certified seed shall be planted on land on which no birdsfoot trefoil, except seed of the same variety which is eligible for certification, has been grown or planted during the three years prior to the one in which the present stand was planted. During the year immediately prior to seeding, the land shall have been in a cultivated crop and the land must be free from volunteer plants. No manure or other contaminating amendments shall be applied during established and productive life of the stand.