Fig. 2. Differences in soil organic C between tillage systems (SOC) from experiments conducted in the Argentine Pampa Region related to experiment duration. (a) SOC calculated for fixed depth, (b) SOC calculated on an equivalent mass basis. SOC = NT – PT (solid circles) denotes SOC differences between no-till and plow till. SOC = NT – RT (open circles) denotes SOC differences between no-till and reduced till (chisel and disk till).