The soil carbon (C) accumulation rate was determined for switchgrass, as compared with selected C3 species in Nova Scotia, Canada. There was no significant effect of crops on total soil C retention, whereas soil 13C signature (δ13C) was enriched by 0.4‰ in switchgrass relative to other C3 species, and C accumulation rate was 0.06 Mg ha−1 yr−1 in the top 30 cm of soil.