The Collaborative International Dictionary of English v.0.48:

Yardland \Yard"land`\ (y[aum]rd"l[a^]nd`), n. (O. Eng. Law)
   A measure of land of uncertain quantity, varying from fifteen
   to forty acres; a virgate. [Obs.]
   [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

YARDLAND, old Eng. law. A quantity of land containing twenty acres. Co.
Litt. 69 a.