catch crop Prairies DCHP-2 (May 2016)
Non-Canadianism
n. — Agriculture
a secondary crop grown between or alongside plantings of a main crop.
Growing catch crops between main crops seems to be a fairly common agricultural practice, especially in the US (see Chart 1).
See also ITP Nelson, s.v. "catch crop", which is marked "Prairie Canada".
Images:

Chart 1: Internet Domain Search, 17 Jan. 2014