关键词: 枯落物分解, 养分, 海拔, 喀斯特地区

Abstract: To understand the characteristics of litter decomposition and nutrient release of common tree species at different altitudes in Guizhou karst region, we selected Cupressus funebris, Cinnamomum bodinieri, Coriaria nepalensis, and Platycarya longipes as the research objects at two altitudes of 600-700 m and 1300-1400 m. The litterbag method was used to study litter mass loss rates and the changes of N, P, and K contents of litter of various tree species in one year. The results showed that the litter mass loss rates of the four tree species at 600-700 m were higher than those at 1300-1400 m. Results of litter decomposition model showed that the values of t_0.5 (the time required for 50% mass loss) and t_0.95 (the time required for 95% mass loss) of litter of each tree species at 600-700 m were smaller than those at 1300-1400 m, but an opposite pattern of decomposition rate constants (k). Litter decomposition rate of different life-form tree species ranked as deciduous tree species > evergreen broad-leaved tree species > coniferous tree species. During litter decomposition, except for species Cupressus funebris and several nutrient release time periods, the N, P and K releases of litter of each species were generally greater at 600-700 m than those at 1300-1400 m. The nutrient release was mainly characterized by release-accumulation or balance and the annual release rate of each nutrient was 32.90%-48.83%. The changes of nutrient contents were closely related to hydrothermal factors at different altitudes. Our results provided a reference basis for forest stand improvement in Guizhou karst region.

Key words: litter decomposition, nutrient, altitude, karst region.