In this study, the addition of exogenous mineral N to soil amended with residues was not found to have any significant effect on macroaggregate formation. Bossuyt et al. [6], however, showed a significant decrease in the formation of large macroaggregates (>2000 mm) measured 14 days after the incorporation of low quality residue. These authors considered that exogenous N decreased microbial activity and, therefore, inhibited the production of microbial metabolites, the binding agents responsible for the formation of large macroaggregates. Similar results were found by Chivenge et al. [8] who explained the decrease in aggregate stability when mineral N was added to a soil amended with a low quality residue (maize) as being due to increased aggregate turnover as a result of the exogenous N accelerating the decomposition of the residue.