By 2012, as a result of years of tillage and corn-soybean production, the SOC on a volume basis in the root
zone was greater in NT system with and without cover vs. the CP and MP systems (Table 2, column 5). In the 0
to 15 cm layer, the NT had higher SOC stocks in the surface layer than CP and MP with and without cover crop
treatments. This may have been due to the reduced decomposition rate, as a consequence of less soil residue
contact, less aeration, and lower soil temperature in NT. The greater SOC stock in the NT system also was result
of less soil erosion due to more residues on the soil surface Table 1, column 9. Loss of macro-aggregates and
SOC could make the tilled soil more vulnerable to water erosion because of a reduction in its slaking resistance.