Chapter 7
Dating of Sclerotia Grains in Andosol
Profiles
Makiko Watanabe, Nobuo Sakagami, and Kiminori Tonosaki
Abstract Sclerotia grains found from soils are not all active for germination but
remain in soil. The age of sclerotia grains existing in soils is able to be estimated by
14 C dating measurement. Sclerotia grains from surface A horizons and buried A
horizons collected from Andosol profiles in central to northern Japan were found to
have ages of 100–200 year BP and 300–1200 year BP, respectively. The carbon
content of the grains tended to decrease as
14 C age increased. The
14 C age of
sclerotia grains indicates the age of individual grain formation and is more likely
to indicate the beginning of soil formation than the
14 C age of humic acid. The Al/C
atomic ratio of the cell wall and the melanin-like spherules of sclerotia grains were
observed using SEM-EDS analysis. Carbon content decreased and aluminum content increased from the outer to the inner portions of the grains, probably owing to
microbial degradation. Additionally, the Al/C ratio of sclerotia grains showed a
significant positive correlation with
14 C age.
Keywords Sclerotia grain · Humic acid · Humin ·
14 C age · Andosol profile
M. Watanabe (*)
Department of Geography, Graduate School of Urban Environmental Sciences, Tokyo
Metropolitan University, Hachioji, Tokyo, Japan
e-mail: m.wata@tmu.ac.jp
N. Sakagami
Department of Biological Production Science, College of Agriculture, Ibaraki University,
Ibaraki, Japan
e-mail: nobuo.sakagami.soil@vc.ibaraki.ac.jp
K. Tonosaki
JEOL Ltd., Tokyo, Japan
e-mail: ktonosaki@jeol.co.jp
© Springer Nature Singapore Pte Ltd. 2021
M. Watanabe (ed.), Sclerotia Grains in Soils, Progress in Soil Science,
https://doi.org/10.1007/978-981-33-4252-1_7
119
Dating of Sclerotia Grains in Andosol
Profiles
Makiko Watanabe, Nobuo Sakagami, and Kiminori Tonosaki
Abstract Sclerotia grains found from soils are not all active for germination but
remain in soil. The age of sclerotia grains existing in soils is able to be estimated by
14 C dating measurement. Sclerotia grains from surface A horizons and buried A
horizons collected from Andosol profiles in central to northern Japan were found to
have ages of 100–200 year BP and 300–1200 year BP, respectively. The carbon
content of the grains tended to decrease as
14 C age increased. The
14 C age of
sclerotia grains indicates the age of individual grain formation and is more likely
to indicate the beginning of soil formation than the
14 C age of humic acid. The Al/C
atomic ratio of the cell wall and the melanin-like spherules of sclerotia grains were
observed using SEM-EDS analysis. Carbon content decreased and aluminum content increased from the outer to the inner portions of the grains, probably owing to
microbial degradation. Additionally, the Al/C ratio of sclerotia grains showed a
significant positive correlation with
14 C age.
Keywords Sclerotia grain · Humic acid · Humin ·
14 C age · Andosol profile
M. Watanabe (*)
Department of Geography, Graduate School of Urban Environmental Sciences, Tokyo
Metropolitan University, Hachioji, Tokyo, Japan
e-mail: m.wata@tmu.ac.jp
N. Sakagami
Department of Biological Production Science, College of Agriculture, Ibaraki University,
Ibaraki, Japan
e-mail: nobuo.sakagami.soil@vc.ibaraki.ac.jp
K. Tonosaki
JEOL Ltd., Tokyo, Japan
e-mail: ktonosaki@jeol.co.jp
© Springer Nature Singapore Pte Ltd. 2021
M. Watanabe (ed.), Sclerotia Grains in Soils, Progress in Soil Science,
https://doi.org/10.1007/978-981-33-4252-1_7
119