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干旱区沙漠化逆转过程植被–土壤碳储量的恢复演变规律研究 被引量:2
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作者 马全林 徐丽恒 +4 位作者 陈芳 张德奎 王新友 靳虎甲 刘有军 《地球科学前沿(汉斯)》 2018年第1期48-59,共12页
碳汇作用是陆地生态系统的重要生态功能之一,也是生态修复关注的重要方面。以地带性植被区为对照,应用空间代替时间的方法,在石羊河中游选择流动沙丘及造林恢复5年、15年和25年沙化土地样地,研究了沙漠化逆转过程沙地生态系统植被–土... 碳汇作用是陆地生态系统的重要生态功能之一,也是生态修复关注的重要方面。以地带性植被区为对照,应用空间代替时间的方法,在石羊河中游选择流动沙丘及造林恢复5年、15年和25年沙化土地样地,研究了沙漠化逆转过程沙地生态系统植被–土壤有机碳储量的恢复演变过程、规律及其影响因素。结果表明:固沙植被碳储量随沙漠化逆转过程先增加后降低,造林恢复25年平均固碳速率仅达到0.05 Mg/hm2?a。尽管沙漠化逆转过程的不同恢复阶段地上植被碳储量大,但是造林恢复5年、15年和25年沙化土地地下植被总碳储量也仅占到地带性植被的22.6%、54.9%和45.3%。0~1 m土壤和生态系统有机碳储量均随沙漠化逆转过程持续增加,造林恢复25年平均固碳速率分别达到0.48 Mg/hm2?a和0.53 Mg/hm2?a,远远高于固沙植被的固碳速率,而且0~5 cm表层土壤是有机碳储量为增长最快的层次。土壤有机碳储量所占比例均在87.5%以上,是沙漠化逆转不同恢复阶段沙化土地和地带性植被区的主要碳库。上述结果证明,固沙造林加速了沙漠化逆转过程,快速提高了沙化土地植被和表层土壤的碳储量,是固定大气CO2于沙地植被和土壤中的有效途径。但是,造林恢复25年沙化土地碳储量与地带性植被间依然存在明显差距,特别是地下植被和深层土壤有机碳储量还存在较大的增长潜力。 展开更多
关键词 沙化土地 固沙造林 植被碳储量 土壤有机碳储量 地带性植被
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The Future is in the Past: Projecting and Plotting the Potential Rate of Growth and Trajectory of the Structural Change of the Chinese Economy for the Next 20 Years 被引量:4
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作者 Jun Zhang liheng xu Fang Liu 《China & World Economy》 SCIE 2015年第1期21-46,共26页
Based on the convergence hypothesis and referring to the experience of East Asian high-performing economies from 1950 to 2010, this paper projects and plots the potential growth rate of the Chinese economy over the ne... Based on the convergence hypothesis and referring to the experience of East Asian high-performing economies from 1950 to 2010, this paper projects and plots the potential growth rate of the Chinese economy over the next 20years. It predicts that the potential growth rate of per capita GDP adjusted by purchasing power parity averages at 6. 02 percent from 2015 to 2035, while the potential GDP growth rate of 2015 would still be above 8percent, which implies that the realized rate of growth has not reached its potential since 2012. Besides, based on the per capita GDP projected and on cross -country comparison, the paper plots the trajectory of structural change of the Chinese economy from 2015 to 2035. The result shows that: (i) the value-added share of primary industry will drop more rapidly than the employment share; (ii) the value-added share of secondary industry will decline and employment share will present an inverted U shape whose turning point will probably come between 2020 and 2025; (iii) both the value-added and employment share of tertiary industry will increase continuously. 展开更多
关键词 Asian economies convergence economic growth structural change the Chinese economy
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