catch-cropping

from The Collaborative International Dictionary of English v.0.48

Catch crop \Catch crop\
   Any crop grown between the rows of another crop or
   intermediate between two crops in ordinary rotation in point
   of time. -- {Catch"-crop`ping}, n.

         Radishes . . . are often grown as a catch crop with
         other vegetables.                        --L. H.
                                                  Bailey.
   [Webster 1913 Suppl.]