Effect of plant species, nitrogen fertilizer and grass age on the dynamics of intra-aggregate SOM

► N amendment and ley stage influenced sward species composition. ► Soil alkane and alcohol signatures reflected changes in the sward composition. ► Importance of large macroaggregates increased with increasing age of the grass ley. ► Intra-aggregate SOM turnover increased with N amendments in the older ley. ► N amendments increased intra-aggregate OM dynamics especially in the smaller WSA size classes.