Source and Accumulation of Soil Carbon along Catena Toposequences over 12,000 Years in Three Semi-Natural <i>Miscanthus sinensis</i> Grasslands in Japan
David S. Howlett,
J. Ryan Stewart,
Jun Inoue,
Masanori Saito,
DoKyoung Lee,
Hong Wang,
Toshihiko Yamada,
Aya Nishiwaki,
Fabián G. Fernández,
Yo Toma
Affiliations
David S. Howlett
United States Agency for International, 1300 Pennsylvania Avenue, NW, Washington, DC 20523, USA
J. Ryan Stewart
Department of Plant and Wildlife Sciences, Brigham Young University, 2124 LSB, Provo, UT 84602, USA
Jun Inoue
Graduate School of Science, Osaka City University, 3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
Masanori Saito
Graduate School of Agricultural Science, Tohoku University, Osaki 989-6711, Japan
DoKyoung Lee
Department of Crop Sciences, University of Illinois at Urbana-Champaign, Turner Hall, 1102 S Goodwin Ave, Urbana, IL 61801, USA
Hong Wang
Interdisciplinary Research Center of Earth Science Frontier, Beijing Normal University, Beijing 100875, China
Toshihiko Yamada
Field Science Center for Northern Biosphere, Hokkaido University, Kita-11, Nishi-10, Kita-ku, Sapporo 060-0811, Japan
Aya Nishiwaki
Field Science Center Kibana Agricultural Science Station, Faculty of Agriculture, University of Miyazaki, 1-1, Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan
Fabián G. Fernández
Department of Soil, Water and Climate, University of Minnesota, 1529 Gortner Avenue, St. Paul, MN 55108, USA
Yo Toma
Research Faculty of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo 060-8589, Japan
Miscanthus-dominated semi-natural grasslands in Japan appear to store considerable amounts of soil C. To estimate the long-term effect of Miscanthus vegetation on the accumulation of soil carbon by soil biota degradation in its native range, we measured total soil C from the surface to a 1.2 m depth along a catena toposequence in three annually burned grasslands in Japan: Kawatabi, Soni, and Aso. Soil C stock was estimated using a radiocarbon age and depth model, resulting in a net soil C accumulation rate in the soil. C4-plant contribution to soil C accumulation was further estimated by δ13C of soil C. The range of total soil C varied among the sites (i.e., Kawatabi: 379–638 Mg, Soni: 249–484, and Aso: 372–408 Mg C ha−1). Catena position was a significant factor at Kawatabi and Soni, where the toe slope soil C accumulation exceeded that of the summit. The soil C accumulation rate of the whole horizon in the grasslands, derived C mainly from C4 plant species, was 0.05 ± 0.02 (Average ± SE), 0.04 ± 0.00, and 0.24 ± 0.04 Mg C ha−1 yr−1 in Kawatabi, Soni, and Aso, respectively. Potential exists for long-term sequestration of C under M. sinensis, but the difference in the C accumulation rate can be influenced by the catena position and the amount of vegetation.
