Suppression of couch grass by Italian ryegrass and broad red clover undersown in barley and field beans

Abstract

Summary: Four annual experiments were carried out on the control of couch grass by undersowing barley and field beans with Italian ryegrass and broad red clover. Pieces of couch grass rhizome 15 cm long were planted in the plots in spring and lifted in late autumn. Couch grass grew more under beans than under barley. Undersowing lessened the growth by a factor of two under barley and by a larger factor under beans, although the total amount of couch lifted from under beans was greater than under barley. Undersowing spring cereals can appreciably retard the spread of couch grass and prevent its rapid spread after harvest if cultivation or spraying is delayed.