Litter decomposition and nitrogen mineralization of soils in subtropical plantation forests of southern China, with special attention to comparisons between legumes and non-legumes

Litter decomposition and nitrogen mineralization were investigated in subtr opical plantation forests in southern China. The CO2-C release from incubat ed litter and the forest floor of Acacia mangium, Acacia auriculaeformis, E ucalyptus citriodora, Pinus elliotii and Schima superba stands were used to estimate relative rates of litter decomposition. Decomposition was not pos itively correlated with litter nitrogen. E. citridora litter decomposed mos t rapidly and A. mangium litter most slowly, both with and without the addi tion of exotic nitrogen. Aerobic incubation and intact soil core incubation at 30 degreesC over a period of 30 days were used to assess nitrogen miner alization of six forest soils. Although there were differences in results o btained using the two methods, patterns between legume and non-legume speci es were the same regardless of method. All soils had pH values below 4.5, b ut this did not prevent nitrification. The dominant form of mineral nitroge n was nitrate for legume species and ammonium for non-legume species. The n itrogen mineralization potential was highest for soils in which legumes wer e growing.