中文摘要：

以龙里典型喀斯特地区马尾松纯林及马尾松-阔叶树混交林为研究对象，研究了两个群落的生物量、营养元素贮量、分布及循环特征。结果表明：马尾松纯林、马尾松-阔叶树混交林的生物量分别为40．62t／hm^2、48．32t／hm^2，混交林的乔木层总生物量比马尾松纯林高18．97％，根系生物量较纯林高65．12％。混交林乔木层各器官营养元素的含量整体大干马尾松纯林，两群落乔木层N、P、K、S的含量表现出一致的趋势，叶〉根〉枝〉干。混交林乔木层各元素的积累量分别比纯林高47．97％～197．67％，凋落物层各元素贮量比纯林高85．40％～318．301％。混交林的年归还量、年存留量和年吸收量均大于马尾松纯林，且各元素循环系数大干马尾松纯林。马尾松林与阔叶树混交可以有效地提高群落生物量和营养元素循环的能力。

英文摘要：

The standing biomass, the accumulation, distribution and biological cycling of nutrients in pure Pinus forest and in Pinus - Hardwood mixed forest are studied in Longli karst area. The results show that the total biomass is 40. 62 t/hm^2 in pure forest, 48.32 t/hm^2 in mixed forest respectively. The biomass in arbor layer of the mixed forest is 18. 97% higher than that in the pure forest, and the biomass in root of the mixed forest is 65.12% higher than that in the pure forest. The contents of nutrient elements in most organs in arbor layer of the mixed forest are higher than that in Pinus forest, and the contents of N, P, K, S of various organs in the two forests show the following orders, leaves 〉 roots 〉 stocks 〉 woods. The accumulative amounts of the six elements in arbor layer of the mixed forest are 47.97%-197. 67% higher than those in arbor layer of Pinus forest. The accumulative amounts of the six elements in litter layer of the mixed forest are 85.40%-318. 301% higher than those in pure forest. The amounts of annual assimilation, annual returning, annual retention, and cycling coefficients of nutrient elements in the mixed forest are all higher than those in pure forest. Planting hardwoods in pure Pinus forest can effectively enhance the biomass and nutrient cycling ability in the community.