Chapter 10
Spatial Distribution of Sclerotia Grains
in Low-pH Forest Soils, Central Germany
Makiko Watanabe and Nobuo Sakagami
Abstract The relationship between the distribution of fungal sclerotia grains and
soil chemical properties was studied in forest soils in the Harz Mountains, Germany.
In addition, the micro-topographical distribution of sclerotia grains was examined in
a single forest stand. Sclerotia grains were predominantly found in surface horizons
(Ah, E horizons) within 10 cm of the soil surface, and the density of grains ranged
from 0.01 to 4.99 g kg
À1 soil. The content of ergosterol, a biomarker of viable fungal
biomass, was correlated with sclerotia grain density in soils. Sclerotia grain density
was higher in soils with high ratios (>0.6) of organic bonding aluminum to amorphous aluminum, and with high contents of exchangeable aluminum (Al
3+ )
(>0.54 g kg
À1 ). The content and state of active aluminum appeared to be the factor
responsible for the development of sclerotia, because sclerotia grains were not
detected in acid soils with a low content of free colloidal aluminum. The intensive
clay destruction associated with past lessivage, or clay particle leaching, may have
depleted the free colloid aluminum in these forest soils. Although there was no clear
relationship between sclerotia distribution and microtopography, field examination
of sclerotia grains in soil showed that the presence of sclerotia grains is an indicator
of soil chemical properties such as acidity and the degree of soil humification.
Keywords Albic luvisols · Sclerotia grain density · Dystric cambisols · Ergosterol ·
Exchangeable aluminum · Haplic podzols · Microtopography · pH value
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
College of Agriculture, Ibaraki University, Ibaraki, Japan
e-mail: nobuo.sakagami.soil@vc.ibaraki.ac.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_10
173
Spatial Distribution of Sclerotia Grains
in Low-pH Forest Soils, Central Germany
Makiko Watanabe and Nobuo Sakagami
Abstract The relationship between the distribution of fungal sclerotia grains and
soil chemical properties was studied in forest soils in the Harz Mountains, Germany.
In addition, the micro-topographical distribution of sclerotia grains was examined in
a single forest stand. Sclerotia grains were predominantly found in surface horizons
(Ah, E horizons) within 10 cm of the soil surface, and the density of grains ranged
from 0.01 to 4.99 g kg
À1 soil. The content of ergosterol, a biomarker of viable fungal
biomass, was correlated with sclerotia grain density in soils. Sclerotia grain density
was higher in soils with high ratios (>0.6) of organic bonding aluminum to amorphous aluminum, and with high contents of exchangeable aluminum (Al
3+ )
(>0.54 g kg
À1 ). The content and state of active aluminum appeared to be the factor
responsible for the development of sclerotia, because sclerotia grains were not
detected in acid soils with a low content of free colloidal aluminum. The intensive
clay destruction associated with past lessivage, or clay particle leaching, may have
depleted the free colloid aluminum in these forest soils. Although there was no clear
relationship between sclerotia distribution and microtopography, field examination
of sclerotia grains in soil showed that the presence of sclerotia grains is an indicator
of soil chemical properties such as acidity and the degree of soil humification.
Keywords Albic luvisols · Sclerotia grain density · Dystric cambisols · Ergosterol ·
Exchangeable aluminum · Haplic podzols · Microtopography · pH value
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
College of Agriculture, Ibaraki University, Ibaraki, Japan
e-mail: nobuo.sakagami.soil@vc.ibaraki.ac.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_10
173