Abstract: In order to understand the decomposition characteristics of foliar litter as affected by rainy pattern in the subtropical evergreen broadleaved forest region, the degradation of lignin and cellulose in different seasons were investigated in foliar litter of Pinus massoniana, Cunninghamia lanceolata, Cryptomeria fortunei, Cinnamomum camphora, Toona ciliate, and Quercus acutissima, six representative tree species in the subtropical evergreen broadleaved forest at the upper reaches of Yangtze River, by litterbag method. After oneyear decomposition, mass loss rates in foliar litter were in order of T. ciliate (72.09%) > C. fortunei (58.61%) > C. lanceolata (51.07%) > Q. acutissima (50.38%) > P. massoniana (31.08%) > C. camphora (27.75%). During the firstyear decomposition, the dynamics of lignin concentration in foliar litter varied with tree species, while cellulose concentration in foliar litter declined continually. Lignin loss rates in foliar litter were in order of T. ciliate (88.36%), Q. acutissima (61.21%), C. fortunei (56.41%), C. lanceolata (55.44%), C. camphora (37.10%), and P. massoniana (24.10%). Meanwhile, cellulose loss rates in foliar litter were ranked in order of T. ciliate (99.22%), C. lanceolata (90.58%), C. fortunei (86.84%), Q. acutissima (84.70%), C. camphora (76.40%), and P. massoniana (71.30%). Seasonal rainfall had a significant (P<0.01) effect on the degradation rates of lignin and cellulose in foliar litter of the tree species studied. The degradation of lignin and cellulose in foliar litter in the rainy season was higher than in the dry season. Furthermore, both lignin and cellulose degradation of foliar litter in the subtropical region occurred mainly in the rainy season. In the dry season of the first decomposing year, lignin in foliar litter showed a similar degradation trend with cellulose. In the seasonal rainy period, however, the degradation rate of cellulose in foliar litter was faster than that of lignin.

Key words: soil nitrogen, controlled release blend bulk urea, soil enzyme activity