A 'non-weed' concept is employed by traditional agriculturalists in a tropical south-eastern Mexico. The non-crop components of cropping systems are classified according to use potential on one hand, and effects on soil and crops on the other. A detailed vocabulary for the management of these plants is presented. Such a classification indicates that local farmers understand the intricate role of non-crop plants in their agricultural activities, in direct contrast with modern day agriculture which considers all weeds as noxious, and thus to be eliminated.
Animals can be integrated in the farm to do most of the weed resource management. For example, ducks are used for selective weed control, because they can often be trained as ducklings to develop a taste for some weeds, and will eat those plants first when allowed to range freely.