Abstract: From March 2005 to April 2007, an investigation was made on the litter fall production and carbon return of  Cunninghamia lanceolata, Schima superba, and their mixed plantations in the Jian’ou Science and Education Park of Soil and Water Conservation, Fujian. In these three plantations, the mean annual litter fall production was from 2470.85 kg·hm^-2·a^-1 to 4285.99 kg·hm^-2·a^-1, and dominated by leaf litter, accounting for 68.62%-87.26% of the total production. In C. lanceolata plantation, the litter fall production peaked in April-May, July, and December; while in S. superba and mixed plantations, this production only peaked in March. Comparing with pure plantations, mixed plantation had a higher litter fall production per tree of broadleaved S. superba while a lower litter fall production per tree of coniferous C. lanceolata. Leaf litter in the three plantations was the main body of the litter falls carbon return, and the total amount of the carbon return was the largest (2.12 t C·hm^-2·a^-1) in mixed plantation and the smallest (1.19 t C·hm^-2·a^-1) in C. lanceolata plantation, which was in accordance with the annual litter fall production of the plantations. This study demonstrated that comparing with pure coniferous or broadleaved plantation, coniferous-broadleaved mixed plantation had higher annual litter fall production and carbon return, and thus, higher potential of C sequestration.

Key words: Cunninghamia lanceolata, Schima superba, mixed plantation, litter fall, carbon return, nitrogen postponing application, winter wheat, water stress, photosynthesis, yield regulation.