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  

作　　者：YinPing CHEN YuQiang LI Tala AWADA JuanJuan HAN YongQing LUO 

机构地区：[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

出　　处：《Journal of Arid Land》2012年第4期411-419,共9页干旱区科学（英文版）

基　　金：supported by the National Natural Science Foundation of China(40901049;31060060);the Major State Basic Research Development Program of China(2009CB 421303);the 'Qing Lan' Talent Engineering Funds of Lanzhou Jiaotong University(QL-08-14A)

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.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.

关 键 词：carbon storage OVERGRAZING EXCLOSURES desertification Horqin Sandy Land 

分 类 号：S792.390.2[农业科学—林木遗传育种] S718.512.1[农业科学—林学]