Zhang, B., Yang, X., Drury, C. F., Reynolds, W. D., He, H. and Zhang, X. 2012. Effects of 49 years of fertilization on the distribution and accumulation of soil carbon under corn cultivation. Can. J. Soil Sci. 92: 835-839. The effects of 49 yr of monoculture corn (Zea mays L.) production with/without chemical fertilizer addition on the origin and distribution of soil organic carbon (C) among the sand (53-2000 µm), silt (2-53 µm), and clay (<2 µm) particle size fractions in the top 20 cm of a clay loam soil were evaluated using the carbon-13 isotope abundance technique. The C derived from corn (newly formed C4-plant C) was greater under chemical fertilization relative to no fertilization in all three size fractions. However, the resident (old) C derived from C3-plants grown prior to corn was similar between the fertilized and unfertilized treatments for each size fraction. Fertilization of monoculture corn had little impact on the amount of native-formed C3-plant C, particularly in the silt and clay fractions, but did increase the amount of newly formed C4-plant C.