Crop-livestock interactions for sustainable agriculture

An important component of the "agricultural revolution" of 18th-century Europe was the introduction of forages into crop rotations. These increased animal production and, in turn, crop yields were raised through improvements in soil fertility due to higher manure output, and through the effects of the forage ley. In the tropics, this type of mixed farming is seldom found: most smallholders do not grow forage crops, and may not even keep any large animals. In many areas, cropping and livestock-keeping are practiced by specialist ethnic groups. In view of this, European-oriented observers often tend to conclude that crops and livestock are not interlinked in tropical farming systems.