• V. O. Targulian, Lomonosov Moscow State University;

Institute of Geography, Russian Academy of

Sciences,

targulian@gmail.com

SELF-ORGANIZATION OF SOIL SYSTEMS,TIME-SCALES AND

ECOLOGICAL SIGNIFICANCE OF PEDOGENIC PROCESSES

The main goal of this presentation is to generalize some existing notions and

concepts of soil systems behavior in time, both under constant and evolving

environment, to propose some considerations and working hypothesis concerning soil self-

development, soil evolution, characteristic times of pedogenic processes and, at least, to assess the ecological significance of the WRB

diagnostic horizons/properties

Main Topics:

• Soil formation as a synergetic process of the soil system self-organization;

• Two main concepts of soil system behavior in time and their harmonization;

• Characteristic times of the WRB diagnostic horizons and specific pedogenic processes.

• Ecological significance of pedogenic processes and the main diagnostic soil horizons

The main working hypothesis of the presentation is that soil formation could be perceived as a synergetic process of the soil system self-organization

The soil formation (in its ideal model) - is a synergetic process of soil system self-organization in time, which

tends to the attractor – mature soil body in steady state;

In this process initial unsteady components and structures of the lithomatrix are transformed into new steady

components and structures of the pedomatrix (soil body, soil cover).

The pedomatrix after its formation becomes by the feedbacks a powerful regulator of the further functioning

of the soil system.

Mountain tropicalfoggy forest (Mexico)

Mountain tropical

Hystic Podzol(Mexico)

Plowed Albeluvisol, Central Russia

Calcareous Arenosols,Pacific low atolls,Cook Islands

Soil as a biospheric bio-abiotic

system on the land surface

ATMOSPHERE

S ITON

ECOSYSTEM

SOIL

WEATHERING

MANTLE

REGOLITH

ABOVEGROUND

STAGE

BELOWGROUND

STAGE

solar-

Gas cyclesn*10-1 – 101 years

Water cyclesn*10-1 – 102 years

Biotic cyclesn*10-1 – 103 years

Place of a soil on crossing of the main matter fluxes & cycles at land surface;Characteristic times of matter renewal in functioning soil system

Endogenic cycles of rocks in lithosphere n*103 – 108 years

Soil system residence time at land surface n*102 – 106 years

Exogenic cyclesof denudation &sedimentationn*102 – 104 years

Anthropo-technogenic cyclesn*101 – 104 years

Ideal model of well-developed

soil & weathering mantle in

humid tropics by the age of

105-6 years;

The total thickness of

SITON

as bio-abiotic exogenic system

O

A1

E

Bt

Mottled clay saprolite

Ortho-biotic

zone

Para-biotic

zone

Meta-biotic

zone

Soil proper as an upper part of

weathering mantle

Medium

and lower

parts of

weathering

mantle

Soil and

weathering

mantle

as in situ

formed

horizonated

body –

SITON

and as a

functioning

CRITICAL ZONE

of a landscape

Red-yellow saprolite

Coarse saprolite

Ground water

Parent rock

0 100

D

E

P

T

H

% volume50

INTERACTIVE COMPONENTS OF MULTIPHASEBIO-ABIOTIC SOIL SYSTEM

SOLID PHASE:

MINERAL AND ORGANO-

MINERAL

PARTICLES

HUMUSLIVING BIOTA

1м

2 м

0POROSITY

GASES

SOLUTIONS

Soil system functioning and soil formation

Functioning (or “life”) of the multiphase soil system starts

immediately at 0-time in the zone of multiple atmo-hydro-bio-litho- interactions within the parent

material (lithomatrix of the soil system).

Labile flux factors – “aggressors”: helio-atmo-hydro-bio; Driving forces of pedogenesis

genic

Exogenic soil-formingpotential of climate and biota - PCB

=

Static immovable site factors– “acceptors”: parent rocks,relief; litho-topo-matrix of soil system

Transformational potential of parent rocks - TPPR

Redistribution potential of relief –RPR

=

Interactions of flux and site factors and their potentials in belowground stage of ecosystem

Emergence of soil functioning multiphase system in enclosing parent material

Processes (fluxes, cycles, exchange reactions) operating in the functioning soil system are not completely closed and reversible, therefore, they produce a range of residual products of functioning (RPF): gaseous, liquid, and solid.

Formation, accumulation, and differentiation of solid RPF in the soil system are the essence of soil formation as in situ development of the soil body (pedomatrix) from the parent material (lithomatrix);

Soil formation (pedogenesis) is the “irreversible time-arrow” of the soil system functioning.

Relation between multiphase processes of soil system functioning and specific pedogenic

processes of formation solid phase pedogenic features

timeL

I t

o m

a t

r I

x

n*101-2

yearsn*103-4 years

n*105-6 years

ortho

para

meta

ortho

para

meta

оrthо

para

meta

ortho

para

meta Sapro-lite

Vertical zones of multiphase soil functioning

Solid phase profile

labileprofiles ofbiota, gases,

solutions,heat

Relationship between functioning of soil system and formation of solid phase soil body

We need to distinguish the multiphase soil system functioning and the solid phase soil body self-organization (self-development) in time:

--multiphase soil system functioning on the land surface is potentially endless process, if not interrupted by denudation or burying,

--solid phase soil body self-organization is potentially self-terminated process, as any synergetic process tending to attractor.

litho-matrix

biota

soild phaseprofile

heat gasessolu-tions

A

E

Bt,m

sapro-lite

ortho ortho ortho ortho

para para para para

meta meta meta meta

time

soil functioning & developmentclimate & biota

0-time

func-tioningwithoutpedogenichorizona-tion

functioning with pedogenic horizonation

solid phase record of long-term functioning

steady state soil body

functioning within steady state

soil body

time

solid phase soil body

present day horizonation of soil functioning

regulates soil functioning

MODEL OF SOIL SELFDEVELOPMENT

feedbacks

feedbacks

Soil systems behavior in time:self-development and

evolution of sols

Possible fates of soil systems in geological time scale: n*10 years4-6

0-time

burying and new pedogenesis

Continuation of “life” and evolution on the land surface

technogenic pollution – “poisoned” pedogenesis

denudationand

pedo-new

genesis

Factors of soil formation soil featuresFactors pedogenic processes soil features

Factors processes of soil functioning pedogenic processes soil features

“meeting” &

interaction of

factors “agressor

s” and factors

“acceptors”

multiphase bio-abiotic interactions

in soil system; in situ labile

horizonation of gases, liquids,

biota and heat in

parent rock;

start of soil system

functioning

fast cycling and renewal

of labile components

(gases, solutions,

biota);

formation & surviving of solid phase

microproducts of soil functioning

selection, accumulation & differentiation of solid phase microproducts

within a soil system;

formation of pedogenic soil macrofeatures,

horizons & profiles;

soil memory

Vertical and lateral

diversity of soil bodies and covers

in space and time

Emerging and functioning of multiphase soil system in solid

phase parent materials

Formation and evolution of pedogenic solid phase structure of soil system in space and

time

Steady-state model of soil development

(Dokuchaev, Jenny, Rode, Yaalon)

Steady-stateSoilfeatures

time, years

Fastprocesses

Slowprocesses

101 102 103 104 105

Soil A

Soil B

Soil C

Progressive pedogenesis Regressive pedogenesis

T0T1 T2 Tn

Evolutionary model of pedogenesis(Johnson, Keller, & Rockwell, 1984)

Soilfeatures

Finity of soil self-development

in constant environment:Under the constant environment, soil development is self-terminated process directed towards the steady state, because all specific pedogenic processes are either self-terminated due to depletion of initial resources, or come to dynamic equilibrium with the environment.

Infinity of soil evolution

in the changing environment: Under the evolving environment without strong erosion and deep burying, soil evolution is an endless process, because specific pedogenic processes are changing following the driving changes of the environment.

Why soil system can approach the steady state?

Self-terminating pedogenic processes

Soil features

Carbonate leaching

time Leaching of bases

from silicates

Dynamically-equilibrium pedogenic processes

Soil features

0

Humus (formation vs decomposition)

Structure

0

Clay formation

Texture differentiation

Primary silicates decomposition

time

Biogenic elements

Soil features steady state of system

Fast pedogenic processes

Slow pedogenic processes

time, yrs.

precipit.

temperature, Possible changes of climate and biota during 102 – 106 years

time, years b.p.

Ideal model of soil and

weathering mantle

self-development

compared with

possible

environment changes

during this time

Soil-forming potential of climate & biotaIn humid regions

biomass

polar

boreal

temperate

tropical

90o 0o45o

90o 45o 0o

biomass

In arid - semihumid regions

latitude

latitude

polar desertstundra-steppes

semideserts

deserts

steppes

Annualprecip., to

Annualprecip., to

(sub)tropical

savannas

rainforcement of weathering and pedogenesis

developing & obliterating soil evolution

weakening of weathering & pedogenesis

inheriting & superimposing soil evolution

Two main models of soil evolution

Individual pedogenic processes (IPP) in soil self-development and evolution

IPP groups FiniteDynamically equilibrium

Irreversible

Reversible

ObliterativeNon-

obliterative

Organic matter accumulation - + - + + - Structuring - + - + + - Pedoturbations - + - + + + Salinization - desalinization - + - + + - Ca(Mg)CO3 migration - + - + + - Weathering + - + - - + Clay formation + - + + - + Leaching from solum + - + - - + Vertical translocations of

clays, Fe, Al, Si + - + - - +

Characteristic times of diagnostic horizons and

specific pedogenic processes

diagnosticfeatures

10 10 10 10 10 10 10 10 100-1 1 2 3 4 5 6 7 years

Characteristic times (CT) of the main diagnostic horizons and properties (WRB)

Short CTn*10 -10

years:

Litter, Cryic,Folic, Ochric,Gleyic, Salic,

Stagnic, Sulphuric, Takyric, Melanic,Plaggic

-1 2Medium CT

n*103 -104 years:

Albic, Andic, Argic, Calcic, Cambic,

Duric, Ferric, Fulvic, Fragic, Gypsic,

Histic, Mollic, Natric, Umbric, Vertic

Long CTn*105 -106

years:Ferralic, NiticPetro-(duric-

plinthic-calcic-gypsic),

Geric & Ferralic prop.

diagnosticfeaturesof SPP

10 10 10 10 10 10 10 10 100-1 1 2 3 4 5 6 7 years

Characteristic times of specific pedogenic processes (SPP) in soil self-development

Fast SPPn*10 -10

years:littering ,

gleyzation,stagnation,salinization,

brunification,cryo-, bio-turbations,structuring,compaction,

etc…

-1 2

Medium-rate SPPn*103 years:mollic, umbric humification, cheluviation,

andosolization,lessivage,

partluvation,fersiallitization,

Fe-,Si-cementation,carbonates migration

etc…

Slow SPPn*104 -10

years:ferralitization

allitization,petro-

cementation,deep sapro-

litization

6

diagnosticfeaturesof SPP

10 10 10 10 10 10 10 10 100-1 1 2 3 4 5 6 7 years

Characteristic times of specific pedogenic processes (SPP) related to soil absolute age

Fast SPPn*10 -10

years

-1 2

Medium-rate SPP

n*10 3-104 years

Slow SPPn*10 -10

years

5 6

young ( alluvial, volcanic, dune) soils tundra & boreal soils

temperate soilstropical soils

• Absolute age of soils and the real duration of the pedogenesis (taking into account the warm and frozen conditions within the each year)

0 1 2 3 4 5 6 7 8 9 10

X 1000 years

T h e H o l o c e n e s o i l a g e

WarmWarm

““age”age”

FrozenFrozen

““age”age”

arctic

tundra

boreal permafrost

temperate seasonally freezing

subtropics & tropics

Interactions of the specific pedogenic processes

Direct linkages(SPP chronochains, which are rather clear)

Fast SPP Medium-rate SPP

Slow SPP

Feedbacks (SPP time bombs, which are often latent)

There are the main areas of synergetic interactions in soil systems

Ecological significance of WRB diagnostic horizons

Diagnostic horizons (WRB) are perceived as attractors of the soil system development:

Diagnostic horizons (WRB) are perceived as attractors of the soil system

development:

«Good» attractors are those states of the soil horizons, upon reaching which the horizons become more favorable for biota than in their previous states (in terms of biological productivity, biodiversity, and reproduction).

«Bad» attractors are those states of the soil horizons, upon reaching which the horizons become less favorable for biota than in their previous states (in terms of biological productivity, biodiversity, and reproduction).

«Good» attractors--diagnostic horizons (WRB) ecologically favorable for biota :

1. Mollic

2. Umbric

3. Chernic

4. Melanic

5. Histic (eutrophic)

6. Hortic

7. Terric

8. Andic

9. Cambic

10. Calcic

11. Nitic

12. Vitric

13. Ochric (?)

«Bad» attractors--diagnostic horizons (WRB) ecologically unfavorable for biota:

1. Albic

2. Argic

3. Cryic

4. Duric

5. Ferralic

6. Ferric

7. Fragic

8. Gypsic

9. Natric

10. Petrocalcic

11. Petroduric

12. Petrogypsic

13. Petroplinthic

14. Plinthic

15. Salic

16. Spodic

17. Sulfuric

18. Takyric

19. Vertic

20. Yermic

21. Abrupt texture

22. Alic properties

23. Geric properties

24. Gleyic properties

25. Stagnic properties

26. Permafrost

MODAL DISTRIBUTION OF SOIL BIOTA AND HORIZONS-ATTRACTORS IN SOIL PROFILE

ОА

Е

В

ВС

ORTHО-

РАRA-

МЕТА-

BIOTIC ZONES IN SOIL

SOLID PHASESOIL PROFILE

«GOOD» ATTRACTORS

«BAD» АТТRACTORS

Conclusions:1. Soil formation in the broad sense is a synergetic process of

the soil system in situ self-organization during its functioning in time and space.

2. Soil formation, sensu stricto, is the transformation of the solid-phase lithomatrix of the soil system into the pedomatrix (soil body, soil cover).

3. Soil system functioning and soil formation are intimately linked but basically different processes: the former is infinite in time, if not interrupted by external factors; the latter, as any self-organization process, is finite in time and tends to reach its attractor (the steady state).

.

4. Soil formation consists of the set of specific pedogenic processes (SPP), which have different characteristic times and rates to reach their individual steady states, i.e. their attractors.

5. SPP could be subdivided into three groups according to their characteristic times: fast SPP, medium-rate SPP and slow SPP, interacting in each soil body.

6. Partial steady states could be reached by faster SPP on the background of slower proceeding SPP, so the direct and feedback synergetic interactions among the different SPP are acting during pedogenesis; the complete steady state is implemented, when the slowest SPP is realized in the soil system.

7. Real duration of active pedogenesis in cold soils is shorter in 3-5 times than their absolute age, so no these soils have reached complete steady state but only partial steady states by fast and medium rate SPP.

.

8. All the diagnostic soil horizons (WRB) are perceived as more or less stable and «mature» attractors of soil self-development. They are separated into «good» and «bad» attractors with respect to biota.

9. «Good» attractors include 13 out of 39 diagnostic horizons and properties (33%). They are mainly shaped by biotic fluxes and cycles, which are comparable to or exceed abiotic fluxes and cycles in their power and capacity. In this case, biota transforms and improves the environment rather than adapts to it.

10. «Bad» attractors include 26 out of 39 diagnostic horizons

and properties (67%). They are shaped by the mutual action of biotic and abiotic fluxes and cycles under the predominance of abiotic ones. In this case, biota adapts to the environment rather than transforms it.

FEW WORDS

TO PROVOKE

THE DISCUSSION

Soil formation - the myths and reality

• Gaia hypothesis (Lovelock, 1989, 1991): biota conducts all processes on the Earth surface, transforms and regulates abiotic environment rather than adapts to it.

• Soil formation is the transformation of parent material by biota with an obligatory consequent increase in its fertility and ecological suitability (Williams, 1930, 1945; Ponomareva, 1975; Van Breeman, 1990).

• Fertility is the main specific property of soil (widespread opinion).

Is it true?

• Soil formation is a global, complex, bio-abiotic process inherent in biosperic planet; it comprises innumerable interactions of biotic

and abiotic fluxes and cycles, which create various specific pedogenic processes (SPP);

• These SPP have different capacities, rates and opposing trends, therefore they build soil bodies as resultant systems with very

complex and discrepant set of soil horizons and features;

• Global pedogenesis is not purposeful, ruled only by biota, harmonious process, on the contrary, it is very contradictory bio-abiotic process in time and space, which can cause positive as well

as negative results for land biota;

• Such understanding of soil formation allows us to assess the role of soil systems in the biosphere more sensibly and to avoid an

overestimated “biospheric euphoria”

7Fertility is a distinctive but not absolutely specific

feature of soil;

Fertility is also the ingraine feature of all bio-abiotic Earth systems including atmosphere and hydrosphere, terrestrial and marine ecosystems

and the biosphere as a whole;

Soil fertility has his own specificity among these systems:

it is “long-term stored” fertility in a form of stable solid phase soil composition and arrangement,

it is “inertial” fertility long-term accumulated in situ within a soil system

THANK YOU FOR YOUR ATTENTION