干旱区生态环境知识资源中心(Arid): 锡林河流域一个放牧羊草群落中碳素平衡的初步估计

Arid

	锡林河流域一个放牧羊草群落中碳素平衡的初步估计
其他题名	Soil carbon budget of garzed leymus chinensis steppe community in the xilin river bain of inner mongolia
	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
来源期刊	植物生态学报
ISSN	1005-264X
出版年	2004
卷号	28 期号:3 页码:312-317
中文摘要	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(Leymus chinensis)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78．2 gC·m-2·a_。，根系碳素输入量的平均值为322．5gC·m~-2·a~-1，碳素输入总量为400．7gc·m~-2·a~-；2)土壤净呼吸量为343．7 gc·m~-2·a～-1，家畜采食量为49．7 gc·m-2·a～，动物(昆虫)采食量为14．7gC·m~-2·a～，地上立枯阶段的淋溶与光化学分解损失为3．2 gC·m12·a-。，碳素输出总量为411．3 gC·m12·a~-1；3)该群落中碳素输出略大于输入，净释放速率为10．6 gC·m~-2·a~-1，0～30 cm土壤中的碳素周转速率为6．2％，周转时间为16年。
英文摘要	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 °C . 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 sam pling 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 continu ously 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 CO2 evolution. Aboveground biomass was measured in 10 - 25 cm diam eter 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 gOm^’a"1, and in puts from root biomass to 30 cm depth averaged 322.5 gCom ~ 2oa ~!. The summed mean annual carbon input of shoot and root materials was approximately 400.7 gCom ~ 2 o a ~!. The annual amount of aboveground biomass consumed by insects averaged 14.7 gOm"2^"1, and the carbon output by leaching or light-chemical oxida-tion was 3.2 gC o m 2 o a !. The annual evolution rate of CO2 from net soil respiration averaged 343.7 gC o m 2a~’. Cattle consumption was 49.7 gC o m~ 2 o a~’. The summed mean annual output was approximately 411.3 gC o m ~ 2 o a ~] and a net carbon release of about 10.6 gCom ~ 2 o a ~’ was calculated. Based on the soil organic carbon density of the field, the turnover rate of soil carbon in 0 - 30 cm depth was 6.2%, with a turnover time of 16 years.Carbon budgets for each of the two years, 1998 and 1999, were quite different. A net carbon release of 75.1 gC’rn" "a"1 was detected in 1999, while a net carbon accumulation of 54.1 gC’irT^a"1 occurred in 1998. By comparing carbon cycling patterns between 1998 and 1999, it was evident that the difference be tween years arose primarily from differences in root production and soil respiration between the two years. Se vere drought in 1999 and record high rainfall in 1998 caused a difference in root NPP by as much as 220.5 gC m ~ 2 o a""1. The root NPP accounted for about 73 % ~ 85 % of the total carbon input in the community, indi cating the importance of the belowground biomass in estimating the carbon budget for this ecosystem. Soil res piration seemed to be less sensitive to drought, with only about a 22.5% decrease in 1999 whereas root NPP decreased by about one half in 1999. Our results indicated that drought, a frequent occurrence in this region, could change this ecosystem from a sink to a source for atmospheric CO2. The degree to which this grassland could become a source of CO2 appeared to depend also on the stocking rate.
中文关键词	放牧
英文关键词	Leymus chinensis steppe
语种	中文
国家	中国
收录类别	CSCD
WOS类目	PLANT SCIENCES
WOS研究方向	Plant Sciences
CSCD记录号	CSCD:1635753
来源机构	中国科学院地理科学与资源研究所 ; 中国科学院植物研究所
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/205659
作者单位	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, 中国; 2.中国科学院地理科学与资源研究所, 北京 100101, 中国
推荐引用方式 GB/T 7714	李凌浩,李鑫,白文明,等. 锡林河流域一个放牧羊草群落中碳素平衡的初步估计[J]. 中国科学院地理科学与资源研究所, 中国科学院植物研究所,2004,28(3):312-317.
APA	李凌浩.,李鑫.,白文明.,王其兵.,闫志丹.,...&董云社.(2004).锡林河流域一个放牧羊草群落中碳素平衡的初步估计.植物生态学报,28(3),312-317.
MLA	李凌浩,et al."锡林河流域一个放牧羊草群落中碳素平衡的初步估计".植物生态学报 28.3(2004):312-317.