Effect of long–term applications of compost and fertilizer NPK on organic C concentrations (g C kg–1 aggregate) in aggregates.

Mean ± standard deviation (n = 4).Increase (%) = (organic C in fertilization treatments – organic C in the control treatment)/organic C in the control treatment×100.Different letters denote significant differences between aggregates with the same treatment (a, b, c, d, e) and between treatments with the same aggregate (x, y, z) at P