On light droughty soils in Canterbury, 'Grasslands Tama' westerwolds ryegrass when overdrilled into lucerne has produced between 1,200 and 5,200 kg/hi1 of dry herbage, in part supplementary and in part complementary to Lucerne growth. Factors affecting growth of the overdrilled ryegrass, such as time of sowing, use of nitrogen at overdrilling and in mid-winter, and of grazing in mid-winter and early spring, are illustrated. On heavier moisture-retentive soils, autumn growth of lucerne reduces establishment of overdrilled grass. At high stocking rates on all-lucerne farms on light lands Tama ryegra'ss can provide high quality greenfeed prior to spring growth of lucerne and thus assist management to better equate feed supply with stock needs. Where Tama ryegrass is sown in cultivated soil, herbage yields far exceed those obtained where it is overdrilled into lucerne. Systems analysis may aid the development of a sound choice for use of the afbove grass with lucerne. Because ruminants are inefficient converters of leaf protein to animal protein the use is suggested oi Lucerne overdrilled with grass for producing leaf-protein concentrate for monogastric animal feeding and partial-protein-extracted residue for feeding ruminants.