The San Luis Valley (SLV) is a high altitude intermountain desert valley with an average precipitation of 180 mm and average elevation of 2341 m. This region is one of the leading areas for fresh-market potato production in the USA. With more than 2,000 wells, irrigated agriculture is key for the economy of this region. However, due to several years of drought, the potato acreage may have to be reduced due to limited groundwater resources since the unconfined aquifer is not being recharged at the same rate of withdrawal. An alternative crop for this region could be cover crops (CC) that can significantly reduce the well water usage by at least fifty percent. The CC will protect water quality due to decreased chemical use, reduce nitrate (NO3-N) leaching, may be effective as a bio-control of soil borne pests, and can be used for hay or grazing. Additional information is needed on how CC will grow with minimum irrigation in this region. Field studies were conducted during 2003 and 2004 on farmed fields. Plant samples were harvested for yield; brought into the laboratory; dried at 55 oC, ground and analyzed for carbon (C) and nitrogen (N) content by combustion using a Carlo Erba automated C/N analyzer. Initial dry weight biomass of oilseed radish (4734 kg/ha) and mustard (4522 kg/ha) were higher than for a sorghum-sudan hybrid (3443 kg/ha) (P<0.05). The mean nitrogen and carbon content averaged across all CC were 61 and 1757 kg/ha, respectively. The CC has potential to be used as a conservation tool, reduce water use, used for hay (sorghum-sudan) and cycle C and N.