气候变化影响的黄土高原农业土壤有机碳与碳排放  

THE EFFECT OF CLIMATE CHANGE ON SOIL ORGANIC CARBON AND CARBON EMISSIONS FOR AGRO-ECOSYSTEMS OF LOESS PLATEAU

作　　者：张凡[1] 李长生 

机构地区：[1]西安交通大学人居环境与建筑工程学院环境与科学技术系,西安710049 [2]Institute for the Study of Earth,Oceans,and Space,University of New Hampshire

出　　处：《第四纪研究》2010年第3期566-572,共7页Quaternary Sciences

基　　金：NASA Terrestrial Ecology sponsored project" Modeling impacts of climate change on carbon dynamics"(08-TE08-13)资助

摘　　要：气候变化直接或间接影响土壤碳库源汇作用,然而目前科学界对土壤碳排放响应气候变化的敏感性还存在很大争议。文章通过对1985～2002年间中国黄土高原地区耕作土壤有机碳动态进行模拟,探讨气候变化对干旱、半干旱地区耕作土壤碳排放的影响效应。结果表明,黄土高原耕作土壤有机碳受气温和降水的共同作用,对降水表现出更强的相关性。有机碳年净变化量受降水的强烈影响,在1990年和2000年降水充足年份表现为土壤有机碳的高增长率,在1995年降水低值年份土壤有机碳年净增长率降至最低。高原内区域间农业土壤有机碳的年变化与降水空间分布、年际变化也表现良好的相关性,气温、降水和蒸发都通过影响土壤含水量从而影响作物生长和土壤碳排放。因本底有机碳含量水平较低,黄土高原耕作土壤整体表现为一个净的碳汇。Climate change has been widely accepted recognized to be an important factor affecting the soil carbon source or sink greatly. The world agro-ecosystems had lost much of their soil organic carbon（SOC） contents due to longterm cultivation with unreasonable management practices during the past centuries. It is estimated that global surface temperatures will continue to increase in the future. However, there is large uncertainty about how the agro- ecosystem SOC would respond to the future climate change. In the present study,a process-based model DNDC was utilized to simulate the long-term（ 1985 -2002）SOC changes occurring in the agro-ecosystems in the Loess Plateau in China. As the farm management practices were kept constant across the simulated 18 years,the inter-annual variations in the modeled SOC contents were assumed to be caused by only the climatic conditions, mainly the temperature and precipitation. The modeled results indicated that the SOC dynamics in the Loess Plateau agro- ecosystems were jointly affected by the temperature and precipitation although precipitation showed to be the dominant factor. In the years（e, g., 1990 and 2000）when the annual precipitations were high,the farmlands gained higher SOC accumulations; while in 1995 with the lowest precipitation value the annual SOC had the least increase for the entire domain. The modeled data indicated that the inter-annual variations in SOC were mainly driven by the crop litter production which was affected by the precipitation abundance in the arid and semi-arid region. The regional inter-annual variations of SOC also showed clear spatial patterns across the domain,which were apparently related to the regional precipitation patterns. In general,the Loess Plateau agro-ecosystem soil showed to be a net carbon sink due to its low background SOC contents.

关 键 词：耕作土壤 碳排放 DNDC 气候变化 

分 类 号：P467[天文地球—大气科学及气象学]