Carbon sequestration in the total and light fraction soil organic matter along a chronosequence in grazing exclosures in a semiarid degraded sandy site in China
YinPing CHEN1, YuQiang LI2, Tala AWADA3, JuanJuan HAN2, YongQing LUO2
1 School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China; 2 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; 3 School of Natural Resources, University of Nebraska, Lincoln, NE 68583, USA
Carbon sequestration in the total and light fraction soil organic matter along a chronosequence in grazing exclosures in a semiarid degraded sandy site in China
YinPing CHEN1, YuQiang LI2, Tala AWADA3, JuanJuan HAN2, YongQing LUO2
1 School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China; 2 Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; 3 School of Natural Resources, University of Nebraska, Lincoln, NE 68583, USA
摘要 Horqin Sandy Land is a fragile, seriously desertified region located in Inner Mongolia of China. Over-grazing is one of the primary drivers of desertification in this region. We investigated whether the establishment of grazing exclosures in areas with active sand dunes enhances soil carbon (C) sequestration and benefits soil re-covery. The results showed that soil organic C storage was 1.4, 1.9, and 3.5 times, and light fraction C storage was 2.3, 3.2, and 4.4 times in the 100-cm topsoil after 7, 12, and 25 years of grazing exclusion, respectively, compared to the case in active sand dunes. The light fraction of soil played an important role in soil C sequestration, although it might not change rapidly to provide an early indication of how soil C is increasing in response to grazing exclusion. The results indicated that soils could potentially sequester up to 13.8 Mt C in 25 years if active sand dunes in the study area were to be protected by exclosures. This corresponds to 12.8% of the estimated carbon loss (107.53 Mt) that has been associated with desertification over the past century in the Horqin Sandy Land. Our results suggested that exclosures have the capacity to increase soil C sequestration; however, decades will be required for soil C to recover to historical grassland levels observed prior to desertification.
Abstract: Horqin Sandy Land is a fragile, seriously desertified region located in Inner Mongolia of China. Over-grazing is one of the primary drivers of desertification in this region. We investigated whether the establishment of grazing exclosures in areas with active sand dunes enhances soil carbon (C) sequestration and benefits soil re-covery. The results showed that soil organic C storage was 1.4, 1.9, and 3.5 times, and light fraction C storage was 2.3, 3.2, and 4.4 times in the 100-cm topsoil after 7, 12, and 25 years of grazing exclusion, respectively, compared to the case in active sand dunes. The light fraction of soil played an important role in soil C sequestration, although it might not change rapidly to provide an early indication of how soil C is increasing in response to grazing exclusion. The results indicated that soils could potentially sequester up to 13.8 Mt C in 25 years if active sand dunes in the study area were to be protected by exclosures. This corresponds to 12.8% of the estimated carbon loss (107.53 Mt) that has been associated with desertification over the past century in the Horqin Sandy Land. Our results suggested that exclosures have the capacity to increase soil C sequestration; however, decades will be required for soil C to recover to historical grassland levels observed prior to desertification.
The National Natural Science Foundation of China (40901049; 31060060), the Major State Basic Research Development Program of China (2009CB 421303), and the ‘Qing Lan’ Talent Engineering Funds of Lanzhou Jiaotong University (QL-08-14A).
通讯作者:
YuQiang LI
E-mail: yqli1975@yahoo.com.cn
引用本文:
YinPing CHEN, YuQiang LI, Tala AWADA, JuanJuan HAN, YongQing LUO. Carbon sequestration in the total and light fraction soil organic matter along a chronosequence in grazing exclosures in a semiarid degraded sandy site in China[J]. 干旱区科学, 2012, 4(4): 411-419.
YinPing CHEN, YuQiang LI, Tala AWADA, JuanJuan HAN, YongQing LUO. Carbon sequestration in the total and light fraction soil organic matter along a chronosequence in grazing exclosures in a semiarid degraded sandy site in China. Journal of Arid Land, 2012, 4(4): 411-419.
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