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Most farms in the semi-arid region of Morocco are mixed cereal-livestock producers. Livestock, dominated by sheep, account for more than one third of farm income but production is far below potential. Low quality cereal straw and weeds from fallow land are the main sources of forage, but provide inadequate nutrition. Fall planted wheat is usually grown in rotation following a year of weedy fallow, The replacement of the weedy fallow by sowing a self regenerating annual Medicago spp,, a system known as ley farming in Australia, was tested in Morocco to determine if it could increase livestock production. Ewe and lamb liveweight gain, wool yield, and forage standing crop during grazing were compared between medic and weedy fallow pastures. Large significant differences (P < 0.05) in forage standing crop and both lamb and ewe liveweight gain occurred in 1990/91 but no differences occurred the previous 2 years when medic was initially sown nor the following 2 years during severe drought. In 1991 lambs gained 67% and ewes gained 60% more liveweight, plus wool yield was 23% higher on medic as compared to weedy fallow. In addition, 3,000 kg ha(-1) of forage remained after grazing medic as compared to 568 kg ha(-1) after weedy fallow.