In eastern Zambia soil carbon (C) and nitrogen (N) in the top 15 cm were higher (p<0.01) in conservation agriculture (CA) compared to traditionally managed corn plots, and soils beneath existing Faidherbia albida trees (a legume being intercropped on CA farms) had higher C and N in the top 15 cm (p<0.05 in trees > 100cm diameter at breast height). Sampling across 10 cropping systems of a 650 ha corn and dairy farm in New York State, bulk density (BD) and organic matter (OM) had a lower coefficient of variation (CV) and smaller sample requirement than soil C concentration. Linear regression models could predict t C ha-1 for the 0-60cm soil profile from measurements of C and BD at the 0-20 or 20-40cm depths (p<0.001, r2 = 0.63 and 0.89, respectively). Soil survey estimates of OM at lower depths were improved with regression models based on field data. iii