Tillage events have an important influence on residue incorporation into soil profiles and soil aggregate disruption, and ultimately influence the net C gain or loss in soils. Thus, our objective was to evaluate tillage‐induced influences on aggregate structure, residue‐derived C stabilization, and the subsequent efficiency of C stabilization in aggregates of no‐till (NT) and tillage management (TM) practices at different depth increments of the soil profile. Uniformly 13C‐labeled wheat residues were added to incubation cores representing soils under NT and TM during a year‐long in situ incubation at a dryland agriculture experiment site. Residue was added directly onto the surface of NT cores, while residues were incorporated into the 0‐ to 5‐, 5‐ to 15‐, and 15‐ to 30‐cm depth increments of the TM cores. We found that residue additions did not have a significant effect (P > 0.05) on aggregate dynamics in either NT or TM, but NT management did result in the greatest stabilization of residue‐derived C (11.2 ± 2.4 g residue C kg−1 soil kg−1 residue C added, P < 0.05) in the macroaggregate (>250‐μm) fraction of the 0‐ to 15‐cm increment. Residue‐derived C stabilization was significantly greater (P < 0.05) in the 0‐ to 30‐cm increment than in the 0‐ to 15‐cm increment of the TM management cores. Overall, our results indicate that, within a plow depth of 15 cm, limiting the tillage‐induced disruption of aggregates has a stronger influence on the efficiency of C stabilization than residue incorporation into the profile via tillage. When residues are distributed to a 30‐cm depth, however, the negative impact of aggregate disruption through tillage appears counterbalanced, with similar efficiencies of C stabilization between the NT and TM practices, possibly due to slower decomposition of residues deeper in the profile.
