Miscanthus, a promising feedstock for the production of lignocellulosic ethanol, will likely see a considerable increase in cultivation and production in the U.S. and Europe in the coming decades. To better predict the effect of this change on soil edaphic resources, we examined a Miscanthus sinensis-dominated grassland in its native range in southern Japan. Soil organic carbon age, accumulated carbon stock, and carbon source were determined on pyrolysis volatile (Py-V) and pyrolysis residue (Py-R) fractions of soil organic matter. Stable carbon isotopic composition of soil organic matter was also determined. Values of total sequestered C summed from two soil profiles (0-1.5m) were 515 and 559MgCha-1. Stable isotope analysis showed that about 66.8% of soil C, ranging from 52.0 to 84.8%, was derived from C4 plants. Variation of soil age indicated by 14C dates of Py-V and Py-R fractions was correlated linearly with soil depths with a R2 value ranging from 0.98 to 0.99. Phytolith data showed an increase in abundance of M. sinensis and Pleioblastus sect. Nezasa following a pyroclastic eruption 7kyrs ago, and a decrease in Sasa sect. Crassinodi from 12 to 7kyrs ago. Organic carbon flux ranged from 0.85 to 1.63MgCha-1yr-1 through 1.5-m soil profiles, and Miscanthus-derived carbon flux was distributed in a similar pattern to the total C throughout the soil profiles. Over a 12,000year history of land use at the Aso caldera, Japan, M. sinensis was found to be a major contributor to soil carbon and a sink for atmospheric CO2, which, under certain constraints, has implications for the potential sequestration of soil carbon under Miscanthus in cultivated conditions.
Bibliographical noteFunding Information:
This project was funded by the Energy Biosciences Institute at the University of Illinois through a grant from the British Petroleum Corporation . We would also like to thank Executive Director Makoto Nakabo, and his staff at the Kyushu Biomass Forum, for providing technical assistance to our field research. We also would like to express our appreciation to the Aso Environmental Office and owners of the study site in Aso, Kumamoto, Japan.
- C grasses
- Miscanthus sinensis
- Soil carbon sequestration