Dryland cropping systems in the Central High Plains often include fallow. The efficiency of the 14-month fallow period associated with the traditional winter-wheat summer fallow system is continually being examined in the face of climate change. Possible alternative cropping systems that may offer improved sustainability continue to be investigated. Integration of Medicago rigidula, a winter annual 'ley' species, in the Central High Plains may improve efficiency by partially or completely replacing fallow. This may lead to increasing returns on investment as well as reduced soil erosion and enhanced sustainable production. Successful Medicago rigidula establishment is the first step in the integration of this ley species into the cropping system. Results from field studies in 2005 show no significant differences in medic biomass between drill and broadcast sowing into high or low surface residue seed beds (p>0.05). However, there were significant differences in medic biomass estimation (counts) between sowing methods (p<0.0001) and between bed preparation methods (p<0.050). There were also significant differences between May and June dryland medic biomass (p<0.0001) indicating a rapid medic growth in the intervening period, and significant differences between irrigated and dryland medic biomass (p<0.0001) demonstrating that water may be a limiting factor in biomass production under dryland cropping systems. Irrigated and dryland plots showed significant differences in seed pod weights (p<0.0001), seed weights per 1,000 seeds (p<0.002), and number of seeds per 25 pods (p<0.002) indicating potential favorable seed setting conditions under dryland cropping systems. An auto-toxicity study showed significant reduction of both medic and wheat seedling growth (p<0.0001) indicating auto-toxicity could be a factor, which influences the self-seeding of Medicago rigidula in the years following initial establishment. Field studies are being repeated in 2006 and early results will be reported.  Additionally, a greenhouse study to test optimum seed sowing depth is also underway.