Temperate intercropping of cereals for forage: a review of the potential for growth and utilization with particular reference to the UK

Cereals grown for forage are increasing in importance in the rations of ruminants in the UK and have the potential to supply high proportions of energy-rich forage in their diets. However, such diets usually require some degree of protein supplementation. Crop mixtures, generally referred to as intercrops, have the potential to boost the forage protein content of diets as well as having a number of agronomic benefits. In this paper, the growth and utilization of annual intercrops is reviewed with particular reference, where feasible, to temperate regions. General agronomic and feeding issues associated with cereal intercrops are outlined together with the practicalities of field-scale management of intercrops in highly mechanized systems. A number of cereal-based intercrop combinations are also considered, concentrating specifically on their value for forage production. The future potential for different combinations is discussed and research recommendations made.