LSs of fields infested with thistles. LS of alfalfa field. LSs of fields infested with chickory, CSs of chickory. LS of field infested with perennial sow thistle. LS of field full of buttercups. LS of field infested with water hemlock. Shot of field of fall rye infested with hoary cress, CU of hoary cress. LS of barley field infested with wild oats. CS of "false flax". LS of stinkweed in field of oats. LS PAN of seeded-down field in Alberta. Shot of summer fallow field with blade weed. Shot of field of leafy spurge, TILT UP to irrigation ditch. Shot of seeding machine in operation, seeding buckwheat. Shot of stiff-toothed cultivator in operation. Shot of one-way cultivator through field of spurge. Shot of four-row corn cultivator in operation. Shot of harrowing machine in operation. Shot of rod weeder in operation. Shot of machine spraying weeds in ditch along road. Shots of dust storms on prairies. Shots of abandoned farm buildings on prairies.