Objective   Effects of the application of pig manure combined with chemical fertilizer on the soil properties and aggregate organic carbon distribution on eroded forest lands were studied for soil improvement and waste utilization.

  Method   In a short-term, pot experiment, 5 fertilizations including control and applications of chemical fertilizer at a rate of 500kg·hm⁻² without or with an addition of pig manure at low (7.5 t·hm⁻²), medium (15 t·hm⁻²), or high (30 t·hm⁻²) level were incorporated into the soil. Distribution, average weight diameter, geometric average diameter, destruction rate, and organic carbon content of the aggregates in the resulting soil were determined.

  Results  (1) The addition of pig manure promoted the water-stable soil microaggregates transforming into macroaggregates. When pig manure was applied at a rate of 15 t·hm⁻², the number of aggregates sized smaller than 0.25 mm decreased by 20.56% and that of aggregates larger than 2 mm increased by 24.92% over control. (2) Pig manure significantly increased the average weight diameter and geometric average diameter of the aggregates (P＜0.05) with a upward trend as the addition rate increased. (3) Pig manure effectively reduced 19.10% on the aggregate destruction rate (PAD) with the 15 t·hm⁻² application rate that delivered the most significant effect (P＜0.05). And (4) pig manure significantly raised the organic carbon content in the soil and aggregates (P＜0.05).

  Conclusion  When combined with chemical fertilizer, pig manure could effectively increase the organic carbon content and improved the aggregate stability of the soil on an eroded forest land. At a rate of 15 t·hm⁻², the pig manure addition significantly increased the average weight diameter and average diameter of the soil aggregates with the highest stability among all treatments, while effectively reduced PAD. At a higher rate of 30 t·hm⁻², the pig manure application significantly increased the organic carbon contents in both non-water-stable and water-stable macroaggregates.