关键词: 凋落物, 琉球松, 亚热带松林, 养分动态, 养分利用效率

Abstract: Land use change has remarkable effects on ecosystem carbon (C) stock. To evaluate the carbon sequestration capability of terrestrial ecosystem under different land use types is of significance in the ecosystem management, and in mitigating the impact of global climate change. Taking sandy grassland (SG), sparse woodland mixed with Pinus sylvestrit-Armeniaca sibirica (SW), and poplar shelterbelt (PS) as test objectives, a quantitative study was made on the ecosystem C stock and allocation under effects of  land use chamges. After the conversion from SG to PS and SW, the aboveground C stock increased at a rate of 0.17 t·hm^-2·a^-1  in SW and 4.45 t·hm^-2·a^-1 in PS. In SG, SW, and PS, the root C stock was 1.382 t·hm^-2, 1.706 t·hm^-2, and 18.541 t·hm^-2, and the soil C stock was 26.11 t·hm^-2, 25.20 t·hm^-2 and 41.36 t·hm^-2, respectively. The rootand soil C stocks in PS after conversed from SG increased at a rate of 1.07 t·hm^-2·a^-1 and 0.5 t·hm^-2·a^-1, respectively. Among the three landuse types, SW had the least variation of C content and stock between soil layers. As a whole, the total C stock was the highest in PS (131. t·hm^-2), followed by in SW (30. t·hm^-2), and in SG (28. t·hm^-2)

Key words: Litterfall, Pinus luchuensis, Subtropical pine forest, Nutrient dynamics, Nutrient use efficiency