Mollic Epipedon - Soil Geography of the USA: A Diagnostic-Horizon Approach - page 39

Table 5.4 Relation of soil-forming factors to the development of mollic epipedons and
intergrades
Area Soil taxa Role of soil-forming factor Citations

Climate

Great plains Mollisols Strongly correlated with the climate of

the Great Plains

Shantz ( 1923 )

India Mollisols Occur in humid tropical regions of

India

Bhattacharyya
et al. ( 2006 )

Buryatia Black

(Mollisols)

Require a minimum of 250-300 mm/yr
precipitation to form

Andreeva
et al. ( 2011 )

China Mollisols Require 500-1,500 mm/yr precipitation

and MAAT of 5-20 C to form

Liu et al. ( 2012 )

World Mollisols Require 300-600 mm/yr precipitation

to form

Rodionov
et al. ( 2010 )

Belgium Mollic Luvisols

(Mollic
Hapludalfs)

SoilGen2 model suggests that soil
temperature and moisture are key to
formation in loess

Finke ( 2012 )

Continental USA Alfisols and
Mollisols

Receive the greatest amounts of Ca in
wet deposition

Goddard
et al. ( 2009 )

High correlation (r 2 Argentina Mollisols ¼ 0.63) between

SOC and ratio of precipitation to
evaporation

Alvarez and
Lavado ( 1998 )

World Mollisols 5-30 % of SOC comprised of black C

from fires

Rodionov
et al. ( 2010 )

Vegetation

Great plains Mollisols The existence of what were to become

Mollisols was strongly correlated
with grassland vegetation of the
Great Plains

Shantz ( 1923 )

Central IL Tama ( ),

Elburn ( ),
Drummer ( )

70-76% of roots are associated with the
mollic epipedon (A horizon)

Douglas
et al. 1967

Central Europe Mollisols Bioturbation a requisite to formation;

form under forest as well as
grassland

Eckmeier
et al. ( 2007 )

Belgium Mollic Luvisols

(Mollic
Hapludalfs)

SoilGen2 model suggests that
bioturbation and fine-root turnover
are key to formation of mollic
epipedon in loess

Finke ( 2012 )

Great plains Mollisols Plant lignin content important to SOC

levels

Parton
et al. ( 1987 )

Parent materials

Buryatia, Russia “Black” soils form from base-rich

eolian and alluvial materials

Andreeva
et al. ( 2011 )

E. Timor Mollisols and

Alfisols

Smectite and hydrous mica are the
dominant minerals

Mella and Mermut
( 2010 )

E. Timor Mollisols and

Alfisols

Dust and limestone parent materials
favor formation

Mella and Mermut
( 2010 )
(continued)