锡林河流域一个放牧羊草群落中碳素平衡的初步估计  

SOIL CARBON BUDGET OF A GRAZED LEYMUS CHINENSIS STEPPE COMMUNITY IN THE XILIN RIVER BASIN OF INNER MONGOLIA

作　　者：李凌浩[1] 李鑫[1] 白文明[1] 王其兵[1] 闫志丹[1] 袁志友[1] 董云社[2] 

机构地区：[1]中国科学院植物研究所植被数量生态学重点实验室,北京100093 [2]中国科学院地理科学与资源研究所,北京100101

出　　处：《植物生态学报》2004年第3期312-317,共6页Chinese Journal of Plant Ecology

基　　金：中国科学院知识创新工程重大项目 (KZCX1_SW_0 1_0 4);国家重点基础研究发展规划项目 (G2 0 0 0 0 1860 3 )

摘　　要：野外调查与历史资料相结合 ,对内蒙古锡林河流域一个放牧羊草 (Leymuschinensis)草原群落的碳素贮量、主要流量和周转速度等进行了估计 ,在此基础上对放牧情况下该群落的碳素收支进行了概算。结果表明 :1)该群落中地上部净初级生产固碳量的两年平均值为 78.2gC·m-2 ·a-1,根系碳素输入量的平均值为 32 2 .5gC·m-2 ·a-1,碳素输入总量为 4 0 0 .7gC·m-2 ·a-1;2 )土壤净呼吸量为 343.7gC·m-2 ·a-1,家畜采食量为 4 9.7gC·m-2 ·a-1,动物(昆虫 )采食量为 14 .7gC·m-2 ·a-1,地上立枯阶段的淋溶与光化学分解损失为 3.2gC·m-2 ·a-1,碳素输出总量为4 11.3gC·m-2 ·a-1;3)该群落中碳素输出略大于输入 ,净释放速率为 10 .6gC·m-2 ·a-1,0～ 30cm土壤中的碳素周转速率为 6 .2 % ,周转时间为 16年。We present a soil carbon budget for a grazed Leymus chinensis steppe community in the Xilin River basin of Inner Mongolia based on historical data and current field measurements. The study site was situated in the southern part of the basin, approximately 1 265 m above sea level. The climate is temperate and semi-arid with a mean annual rainfall of 350 mm and annual mean temperature of 0.3 ℃. The dark chestnut soil profile is about 1 m in depth with a 10-20 cm thick humus layer, a pH of 7.4 to 8.3, and an organic C content of 1.53%-1.37% in the upper 0-20 cm layer. A grazed stand (43°32′58″ N, 116°40′34″ E) outside the L. chinensis permanent plot of the Inner Mongolian Grassland Ecosystem Research Station was chosen as a sampling plot. Vegetation consisted mainly of L. chinensis, Stipa grandis, Agropyron cristatum, and Cleistogenes squarrosa, which accounted for 80% of the total aboveground biomass. The pasture has been grazed continuously for more than 40 years at a moderate stocking rate with about 2/3 of the above-ground biomass consumed annually. Soil respiration, and aboveground biomass, and root biomass measurements were initiated May 31, 1998 and measured every ten days over two growing seasons until October 14, 1999. The alkali absorption method was used to measure soil respiration. Root respiration was evaluated indirectly by relating the amount of root biomass under the chamber to rates of CO 2 evolution. Aboveground biomass was measured in 10-25 cm diameter circular plots using the harvest method. The maximum biomass value measured during the growing season was taken as the annual net primary productivity (NPP). Root biomass was measured to 30 cm depth, and the root productivity was estimated using the annual increment of growth, as defined by Dahlman and Kucera. Food consumption by insects was determined using the cage-feeding method by using a series of cages with different insect population densities. The annual average carbon input from aboveground biomass production was 78.2 gC·m

关 键 词：锡林河流域 放牧 羊草 群落 碳素平衡 土壤呼吸 周转速率 

分 类 号：S812[农业科学—草业科学]