of this title, (ii) who lawfully acquired his lands as an entire farm unit under the Federal reclamation laws from the United States or, in the case of a widow, widower, heir, or devisee, from a spouse or ancestor, as the case may be, who so acquired them, and (iii) who conveys, free from all encumbrances, to the United States all of his lands served by the project or such portion thereof as the Secretary may designate.