我国西北地区不同类型草原土壤有机质的稳定碳同位素特征研究  

A Study on the Characteristics of Soil Stable Carbon Isotope Composition in Different Types of Grassland in Northwest China

作　　者：张月鲜[1] 孙向阳[1] 张林[1] 李素艳[1] 

机构地区：[1]北京林业大学林学院,北京100083

出　　处：《土壤通报》2013年第2期348-354,共7页Chinese Journal of Soil Science

基　　金：科技部基础性工作专项(2007fy210300);国家自然基金(30671660);教育部新世纪优秀人才支持计划(NCET-05-0137)资助

摘　　要：以内蒙古、新疆和西藏3个地区为例,对我国西北地区荒漠草原、亚高山草甸、高山草甸和高寒草原土壤有机碳(SOC)含量及其有机质δ13C值进行测定和分析,结果显示:表层土壤SOC含量随海拔升高逐渐增加,具体表现为内蒙古四子王旗荒漠草原<新疆荒漠草原<新疆亚高山草甸<西藏高山草甸<西藏高寒草原;SOC含量随着深度增加急剧减少,减少幅度依次为92.26%、77.9%、77.67%、61.58%和88.55%;内蒙古四子王旗荒漠草原表层土壤有机质δ13C值与优势植被有机质δ13C值极显著相关(r=0.555,P<0.01),分馏程度大于其他地区;各地区土壤有机质δ13C值均随深度的增加而表现出不同程度的富集,其中内蒙古四子王旗和新疆地区δ13C值富集程度相对较高,分别为12.66‰和16.53‰,说明这两个地区土壤有机质分解程度相对较高,且气候、植被和土壤发育特性是控制有机质δ13C值分布的主要因素,同时也表明以上地区曾经可能经历过剧烈的气候变化,植被也发生过相应演替。According to the geographic distribution of grassland in northwest China, soil samples from Inner Mongolia, Xinjiang and Tibet were collected, and the contents of soil organic carbon （SOC） and values of soil stable carbon isotope （813C value） were also tested. The results showed that SOC contents of top soil （0 - 3 cm） increased with the increase of elevation; while SOC contents decreased with the increase of soil depth vertically, the variation ranges were 92.26%, 77.9%, 77.67%, 61.58% and 88.55%, respectively; the 813C values of top soil and the dominant vegetation were significantly correlated with each other in the desert steppe of Inner Mongolia （r -- 0.555,P 〈 0.01）, and the fractionation between soil and vegetation was higher than other areas; The 813C values of different soil profiles increased dramatically with soil depths, and the fractionation of 813C value in Inner Mongolia and Xinjiang were higher, which were separately 12.66%~ and 16.53%~. These results showed that the rate of SOC decomposition was higher in desert steppe of Inner Mongolia and Xinjiang, and the climate, vegetation and characteristics of soil were the main factors which influenced the vertical distribution of 8~3C values. Besides, the significant fractionation of ~13C values in these areas also indicated that the climate and vegetation could have changed violently in desertification grassland in northwest China.

关 键 词：草原 土壤有机质 δ13C值 气候及植被变迁 

分 类 号：S155.47[农业科学—土壤学] S153.6[农业科学—农业基础科学]