Podzols - Europa

EUROPEAN SUMMER SCHOOL ON SOIL SURVEYEUROPEAN SUMMER SCHOOL ON SOIL SURVEYEUROPEAN COMMISSION, DIRECTORATE GENERAL, JOINT RESEARCH CENTER ,INSTITUTE FOR ENVIRONMENT &

SUSTAINABILITY

Endre DobosEndre DobosUniversity of MiskolcUniversity of Miskolc

Dept. of Physical Geography and Environmental SciencesDept. of Physical Geography and Environmental Sciences

Mineral soils conditioned by (sub-) humid climate…

The Podzols


SUSTAINABILITY

The definition of Podzols

Soils, having a Soils, having a spodicspodic horizon starting within 200 cm from the horizon starting within 200 cm from the soil surface, underlying an soil surface, underlying an albicalbic, , histichistic, , umbricumbric or or ochricochric horizon, horizon, or an or an anthropedogenicanthropedogenic horizon less than 50 cm thick.horizon less than 50 cm thick.


SUSTAINABILITY

Common soil unitsCommon soil unitsDensicDensic: having a cemented spodic horizon (Ortstein): having a cemented spodic horizon (Ortstein)CarbicCarbic: cemented, but does not contain enough amorphous iron: cemented, but does not contain enough amorphous ironRusticRustic: cemented mainly by OM and aluminium: cemented mainly by OM and aluminiumHisticHistic: having a histic horizon: having a histic horizonGelicGelic: having permafrost undernaeth: having permafrost undernaethAnthricAnthric: showing evidences of cultivation: showing evidences of cultivationGleyicGleyic:: having gleyic properties within a meterhaving gleyic properties within a meterUmbricUmbric:: having an umbric horizonhaving an umbric horizonPlacicPlacic:: having a thin iron panhaving a thin iron panSkeleticSkeletic: having gravel or other coarse fragments in the profile: having gravel or other coarse fragments in the profileStagnicStagnic:: having stagnic propertieshaving stagnic propertiesLamellicLamellic:: having clay illuviation lemallaes having clay illuviation lemallaes FragicFragic:: having a fragic horizonhaving a fragic horizonEnticEntic:: having no albic horizon (young soils)having no albic horizon (young soils)HaplicHaplic: : havinghaving nothingnothing specialspecial toto mentionmention


SUSTAINABILITY

Geographic distribution

•• an estimated 485 million hectaresan estimated 485 million hectares•• mainly in temperate and boreal regions on the Northern Hemisphermainly in temperate and boreal regions on the Northern Hemisphere e (t(they are extensive in Scandinavia, northwest Russia and Canadahey are extensive in Scandinavia, northwest Russia and Canada))•• bbesidesesides `̀zonalzonal' ' PodzolsPodzols, there are smaller occurrences of`, there are smaller occurrences of`intrazonalintrazonal' ' PodzolsPodzols, both in the Temperate Zone and in the tropics., both in the Temperate Zone and in the tropics.

•• ttropicalropical PodzolsPodzols occupy less than 10 million hectaresoccupy less than 10 million hectares•• mainly in residual sandstone weathering in mainly in residual sandstone weathering in perhumidperhumid regions and in regions and in alluvial quartzalluvial quartz sands, e.g. in uplifted coastal areassands, e.g. in uplifted coastal areas ((important important occurrences are found along the Riooccurrences are found along the Rio Negro and in the Negro and in the GuianasGuianas in in South America, in the South America, in the MalesianMalesian region (region (KalimantanKalimantan, Sumatra, , Sumatra, IrianIrian), ), and in northern and southern Australiaand in northern and southern Australia


SUSTAINABILITY


SUSTAINABILITY

The distribution of Podzols over the

Eurasian continent


SUSTAINABILITY

Profile development: Profile development:

CC

BhsBhs

EE

AhAh

OO


SUSTAINABILITY

A spodic horizon must:1.1. have have -- a a MunsellMunsell hue of 7.5YR or redder with value of 5 or less and hue of 7.5YR or redder with value of 5 or less and chromachroma of 4 or less of 4 or less when moistwhen moist and crushed; and crushed; or or -- a hue of 10YR with value of 3 or less and a hue of 10YR with value of 3 or less and chromachroma of 2 or less when moist and crushed; of 2 or less when moist and crushed; or or -- a suba sub--horizon, which is 2.5 cm or more thick and which is continuouslyhorizon, which is 2.5 cm or more thick and which is continuously cemented by cemented by a combination of organic matter and aluminium, with or without ia combination of organic matter and aluminium, with or without iron (`thin iron pan'); ron (`thin iron pan'); or or -- distinct organic pellets between sand grains; distinct organic pellets between sand grains; and and

2.2. contain 0.6 percent or more organic carbon; contain 0.6 percent or more organic carbon; and and 3.3. have a soilhave a soil--pH (1:1 in water) of 5.9 or less; pH (1:1 in water) of 5.9 or less; and and 4.4. have have -- at least 0.50 percent at least 0.50 percent AloxAlox + ½+ ½FeoxFeox and have two times or more and have two times or more AloxAlox+ ½+ ½Feox Feox than an than an

overlying overlying umbricumbric,, ochricochric, , albicalbic or or anthropedogenicanthropedogenic horizon; horizon; or or -- an ODOEan ODOE--value (`Optical Density of the Oxalate Extract') of 0.25 or morevalue (`Optical Density of the Oxalate Extract') of 0.25 or more, which also , which also isis two two ttimesimes or more the value of the overlying horizons; or more the value of the overlying horizons; and and 5.5. have a thickness of 2.5 cm or more and an upper limit below 10 chave a thickness of 2.5 cm or more and an upper limit below 10 cm from the mineral m from the mineral soil surface, unless permafrost is present within 200 cm depth.soil surface, unless permafrost is present within 200 cm depth.


SUSTAINABILITY


SUSTAINABILITY

Parent material:Parent material: unconsolidated weathering materials of unconsolidated weathering materials of siliceous rock, prominent on glacial till, and alluvial and siliceous rock, prominent on glacial till, and alluvial and aeolianaeolian deposits of deposits of quartziticquartzitic sands. sands.

PodzolsPodzols in boreal regions occur on almost any rock.in boreal regions occur on almost any rock.

Environment:Environment: mainly in temperate and boreal regions of the mainly in temperate and boreal regions of the northern hemisphere, in level to hilly land under heather northern hemisphere, in level to hilly land under heather and/or coniferous forest; in the humid tropics under light and/or coniferous forest; in the humid tropics under light forest.forest.


SUSTAINABILITY


SUSTAINABILITY

Associations with other Reference Soil GroupsAssociations with other Reference Soil Groups

•• PodzolPodzol--HistosolHistosol--GleysolGleysol combinations are common in plains combinations are common in plains with with quartziticquartzitic sand and a shallow water table in the Temperate sand and a shallow water table in the Temperate Zone.Zone.•• CryosolCryosol--PodzolPodzol linkages are found at high latitudes and in places linkages are found at high latitudes and in places also at high altitude. also at high altitude. •• Tropical Tropical PodzolsPodzols are associated with poor are associated with poor quartziticquartzitic ArenosolsArenosols, , with with GleysolsGleysols and with and with FerralsolsFerralsols..


SUSTAINABILITY

Plant litterPlant litter

Soluble organic matter (Low Molecular Weight acids and non acidiSoluble organic matter (Low Molecular Weight acids and non acidic humus compounds)c humus compounds)

Microbial attack (mainly fungi)Microbial attack (mainly fungi)

Chelation

Fe and Al Fe and Al chelateschelates are leached with the waterfrontare leached with the waterfront

Mineral weatheringMineral weatheringFeFe3+3+

AlAl3+3+

FeFe3+3+

AlAl3+3+

AlAl3+3+

FeFe3+3+

Saturation, loss of surface chargeSaturation, loss of surface charge

Precipitation, formation of the Precipitation, formation of the spodicspodic horizonhorizon


SUSTAINABILITY


SUSTAINABILITY

GroundwaterGroundwater

Leached horizonLeached horizon

Plant litterPlant litterThin Ah horizonThin Ah horizon

Leaching of the Leaching of the chelateschelates PrecipitationPrecipitation


SUSTAINABILITY


SUSTAINABILITY

Mineral soils conditioned by

(sub-) humid climate…

The Planosols


SUSTAINABILITY

Definition of PlanosolsSoils havingSoils having1.1. an an eluvialeluvial horizon or loamy sand or coarser materials, the horizon or loamy sand or coarser materials, the lower boundary of which is marked, within 100 cm from the lower boundary of which is marked, within 100 cm from the soil surface, by an soil surface, by an abrupt textural changeabrupt textural change associated with associated with stagnicstagnic soil propertiessoil properties above that boundary, and above that boundary, and

2.2. no no albeluvicalbeluvic tonguingtonguing


SUSTAINABILITY

Common soil units:ThionicThionic: having a sulfuric horizon or sulfuric material: having a sulfuric horizon or sulfuric materialHisticHistic: having a histic horizon: having a histic horizonGelicGelic: having permafrost: having permafrostVerticVertic:: having vertic horizon or vertic propertieshaving vertic horizon or vertic propertiesEndosalicEndosalic:: having a salic horizon within 50 and 100 cmhaving a salic horizon within 50 and 100 cmGleyicGleyic:: having gleyic propertieshaving gleyic propertiesPlinthicPlinthic:: having a plinthic horizonhaving a plinthic horizonMMollicollic:: having a mollic horizonhaving a mollic horizonGypsicGypsic:: having a gypsic horizonhaving a gypsic horizonCalcicCalcic:: having a calcic horizon or secondary carbonate having a calcic horizon or secondary carbonate concentrationsconcentrationsAlicAlic:: having an argic horizon with more than 50 % Al having an argic horizon with more than 50 % Al saturationsaturationLuvicLuvic:: having an argic horizon with more than 50 % base having an argic horizon with more than 50 % base saturationsaturation


SUSTAINABILITY

UmbricUmbric:: having a umbric horizonhaving a umbric horizonArenicArenic:: having a loamy fine sand structure or coarserhaving a loamy fine sand structure or coarserCalcaricCalcaric:: calcareous within the 20calcareous within the 20--50 cm 50 cm AlbicAlbic:: having an albic horizonhaving an albic horizonFerricFerric:: having a ferric horizonhaving a ferric horizonAlcalicAlcalic:: having a pH of 8.5 or morehaving a pH of 8.5 or moreSodicSodic:: having a significant portion of Na (and Mg) on having a significant portion of Na (and Mg) on the colloid surfacesthe colloid surfacesAlumicAlumic:: having 50 % or more Al saturationhaving 50 % or more Al saturationDystricDystric:: less than 50% base saturationless than 50% base saturationEutricEutric:: more than 50 % base saturationmore than 50 % base saturationRhodicRhodic:: having a hue3.5 YR or redderhaving a hue3.5 YR or redderChromicChromic:: showing evidence of colorationshowing evidence of colorationHaplicHaplic: having no any spacialty: having no any spacialty


SUSTAINABILITY

Stagnic propertiesStagnicStagnic properties are indicative of reducing conditions, properties are indicative of reducing conditions,

evident from:evident from:1.1. a value of a value of rHrH in the soil solution of in the soil solution of 19 or less19 or less; ;

or or 2.2. presence of free Fepresence of free Fe22++ as shown by the appearance as shown by the appearance of a strong red colour on a freshly broken surface of a of a strong red colour on a freshly broken surface of a fieldfield--wet wet soil samplesoil sample after spraying it with a 9.2% α,α after spraying it with a 9.2% α,α dipyridyldipyridyl solution in 10% acetic acid; solution in 10% acetic acid;

and and 3.3. an an albicalbic horizon or a horizon or a stagnicstagnic colour pattern incolour pattern in

more than 50 percent of the soil volume if more than 50 percent of the soil volume if ththe soil is e soil is undisturbed; undisturbed; or or in 100 percent of the soil volume if the in 100 percent of the soil volume if the ssurfaceurface horizon horizon isis disturbed by ploughing.disturbed by ploughing.


SUSTAINABILITY


SUSTAINABILITY

An An abrupt textural changeabrupt textural change is indicated byis indicated by::

doubling of the clay content within a vertical distance doubling of the clay content within a vertical distance of 7.5 cm if the overlying horizon has less than 20 of 7.5 cm if the overlying horizon has less than 20 percent clay; percent clay; or or 20 percent (absolute) clay increase within 7.5 cm if 20 percent (absolute) clay increase within 7.5 cm if the overlying horizon has 20 percent or more clay. In the overlying horizon has 20 percent or more clay. In this case some part of the lower horizon should have this case some part of the lower horizon should have at least twice the clay content of the upper horizon.at least twice the clay content of the upper horizon.


SUSTAINABILITY

AlbeluvicAlbeluvic tonguestongues must:must:

1.1. have the have the colour of an colour of an albicalbic horizonhorizon; ; and and 2.2. have greater depth than widthhave greater depth than width, with the following , with the following

horizontal dimensions: horizontal dimensions: 5 mm or more in clayey 5 mm or more in clayey argicargic horizons; horizons; or or 10 mm or more in clay loamy and 10 mm or more in clay loamy and siltysilty argicargic

horizons; horizons; or or 15 mm or more in coarser (silt loam, loam or sandy 15 mm or more in coarser (silt loam, loam or sandy

loam) loam) argicargic hohorizonsrizons; ; andand3.3. occupy more than 10 percentoccupy more than 10 percent of the volume of the of the volume of the

upper 10 cm part of the upper 10 cm part of the argicargic horizon, estimated from or horizon, estimated from or measured on both measured on both vverticalertical and horizontal sections; and horizontal sections;

and and 4.4. have a particle size distribution matching that of the have a particle size distribution matching that of the

eluvialeluvial horizon overlying the horizon overlying the argicargic horizon.horizon.


SUSTAINABILITY

Geographic distribution of Geographic distribution of PlanosolsPlanosols

The world's major The world's major PlanosolPlanosol areas lie in subtropical and areas lie in subtropical and temperate regions temperate regions with clearly alternating wet and dry with clearly alternating wet and dry seasonsseasons, in Latin , in Latin AAmericamerica (southern Brazil, Paraguay, (southern Brazil, Paraguay,

Argentina), southern and eastern Africa (Argentina), southern and eastern Africa (SahelianSahelian zone, zone, East and southern Africa), the East and southern Africa), the EEastern United States, astern United States,

southeast Asia (Bangladesh, Thailand) and in Australia. southeast Asia (Bangladesh, Thailand) and in Australia. Their total extent is estimated at some 130 million Their total extent is estimated at some 130 million

hectares worldhectares world--wide. wide.


SUSTAINABILITY


SUSTAINABILITY

The distribution of Planosols over the Eurasian continent


SUSTAINABILITY

Associations with other Reference Soil GroupsAssociations with other Reference Soil Groups

PlanosolsPlanosols occur predominantly in occur predominantly in flat landsflat lands but can also but can also be found in the be found in the lower stretches of slopeslower stretches of slopes, ,

••in a strip intermediate between uplands with in a strip intermediate between uplands with AcrisolsAcrisolsor or LuvisolsLuvisols, , ••and lowland (plain or basin) areas with and lowland (plain or basin) areas with VertisolsVertisols. .

PlanosolsPlanosols occur also occur also on terraceson terraces or somewhat higher up,or somewhat higher up,together with together with AcrisolsAcrisols or other soils with an or other soils with an argicargicsubsurface horizon. subsurface horizon.


SUSTAINABILITY

Profile development:Profile development:

CC

BB

EE

AA

Destruction and/or removal of Destruction and/or removal of clay produced relatively coarseclay produced relatively coarse--textured bleached surface soil textured bleached surface soil

abruptlabruptly y overlying finer subsoil. overlying finer subsoil. Impeded downward water Impeded downward water

percolation accounts for percolation accounts for stagnicstagnicsoil properties in the bleached soil properties in the bleached

horizon.horizon.


SUSTAINABILITY

Parent materialParent material: mostly clayey alluvial and : mostly clayey alluvial and colluvialcolluvial deposits.deposits.

Environment:Environment: seasonally or periodically wet, level (plateau) areas, seasonally or periodically wet, level (plateau) areas, mainly in submainly in sub--tropical and temperate, semitropical and temperate, semi--arid and subarid and sub--humid humid regions with light forest or grass vegetation.regions with light forest or grass vegetation.

Use:Use: PlanosolsPlanosols are poor soils. In regions with a warm summer season are poor soils. In regions with a warm summer season they are mostly under wetland rice. Elsewhere, they are mostly under wetland rice. Elsewhere, PlanosolsPlanosols are sown to are sown to drylanddryland (e.g. fodder) crops or used for extensive grazing. Many (e.g. fodder) crops or used for extensive grazing. Many PlanosolPlanosol areas are not used for agriculture.areas are not used for agriculture.


SUSTAINABILITY


SUSTAINABILITY

Genesis of Genesis of PlanosolsPlanosols::

The finer textured subsurface soil may show signs of clay The finer textured subsurface soil may show signs of clay illuviationilluviation; it is only slowly ; it is only slowly permeable to water. Periodic stagnation of water directly above permeable to water. Periodic stagnation of water directly above the denser the denser ssubsurfaceubsurfacesoil produced typical soil produced typical stagnicstagnic soil properties in the bleached, soil properties in the bleached, eluvialeluvial horizon. (And in horizon. (And in many soils also to mottling in the upper part of the clayey subsmany soils also to mottling in the upper part of the clayey subsoil). oil).

The `abrupt textural change' from coarse textured surface soil tThe `abrupt textural change' from coarse textured surface soil to finer subsoil can be o finer subsoil can be caused by:caused by:

1. 1. GeogeneticGeogenetic processesprocesses2. Intensive clay 2. Intensive clay illuviationilluviation3. Increased clay 3. Increased clay illuviationilluviation due to the stagnant water and due to the stagnant water and ferrolysisferrolysis (chemical (chemical pedogenetic processes) pedogenetic processes)


SUSTAINABILITY

Increased clay Increased clay illuviationilluviation due to the stagnant water and due to the stagnant water and ferrolysisferrolysis ((Oxidation reduction sequenceOxidation reduction sequences)s)

Reduction of iron uses HReduction of iron uses H++ and results in the formation of free and results in the formation of free FeFe2+2+

FeFe2+2+ replaces basic replaces basic cationscations from the clay surfaces, which will from the clay surfaces, which will be partly leached out be partly leached out from from the soilthe soil, Al, Al--polymers are forming polymers are forming and trapped in the interlayer spaces of the clays (base and trapped in the interlayer spaces of the clays (base saturation decreases, CEC decreases, water holding capacity saturation decreases, CEC decreases, water holding capacity decresases)decresases)

ReRe--oxidation of the Feoxidation of the Fe2+2+ to ferric iron releases Hto ferric iron releases H++ which which replaces replaces cationscations from the clay surface and form Hfrom the clay surface and form H--clay.clay.

HH--clays are clays are peptisizedpeptisized or dispersed and being leached down or dispersed and being leached down in the stagnic water layer in the stagnic water layer totoward to the top of the ward to the top of the BB--horizonhorizon


SUSTAINABILITY

Podzols - Europa

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