If a practice is not performed by a farmer, it must, among other
things, be performed ``on a farm'' to come within the secondary meaning
of ``agriculture'' in section 3(f). Any practice which cannot be
performed on a farm, such as ``delivery to market,'' is necessarily
excluded, therefore, when performed by someone other than a farmer (see
Farmers Reservoir Co. v. McComb, 337 U.S. 755; Chapman v. Durkin, 214 F.
2d 360, cert. denied 348 U.S. 897; Fort Mason Fruit Co. v. Durkin, 214
F. 2d 363, cert. denied 348 U.S. 897). Thus, employees of an alfalfa
dehydrator engaged in hauling chopped or unchopped alfalfa away from the
farms to the dehydrating plant are not employed in a practice performed
``on a farm.''