soil orders.ppt

agriculture

1. Soil classification



1. Economic 2.Physical 3. Chemical 4. Geological 5. Physiographic 6. Other types

Soil productivity
(Revenue Dept.)
Texture,
structure
Calcareous,
alkaline ,
acidic etc.,
(i) Residual/sedimentary.
(ii) Transported soils
Landscape-
Terrace soils, hilly
soils, Upland,
low land etc
OM content –
organic,
inorganic soils
Climate –
Arid,
semiarid,
humid, sub
humid soils
Vegetation-
grasslands,
forest soils
etc.,
Early systems of classification,
Soil classification-Early systems of classification, diagnostic
horizons

2. Soil Taxonomy
PurposeofSoilTaxonomy:
1.Organizeknowledgeaboutsoils
2.Understandrelationshipsamongdifferentsoils
3.Establishgroupsorclassesforpracticalpurposes.
a.predictingbehavior
b.identifyingbestuses
c.estimatingproductivity
d.extendingresearchresults
4.Knowledgeoflocationsofvarioussoilorders
5.Investigate how soil temps and moistures are categorized

3. Salient features of soil taxonomy
Itisbasedonmeasurablesoilproperties
Itconsidersallsuchpropertieswhichaffectsoil
genesis
Thenomenclatureismostlogical&helpsinrelating
theplaceoftaxon
Itistrulymulti-categoricalsystemwith6categories
Itisanorderlyschemewithoutprejudiceand
facilitateeasyrememberingofobjects.

4. Advantagesof soil taxonomy
1.Itpermitstheclassificationofsoilsratherthansoil
formingprocesses
2.Itfocusesonsoilsratherthanrelatedsciencessuchas
geologyandclimatology
3.Itpermitstheclassificationofsoilsofunknowngenesis
4.Itpermitsthegreateruniformityofclassification
5.The soil with a different genesis but having identical
properties are classified within the same unit

5. Soil Classification/Taxonomy
Based on soil profile characteristics and
the concept of soils as a natural body.
Observable properties: color, texture, structure,
pH, O.M…
Soil Profile
Hierarchical
Genesis
1883V.V. Dukachaev: climate, vegetation, soil
( Founder of Modern Pedology)
1927C.F. Marbut (USDA) applied to U.S. (1965)
(Founder of Ameican Pedology)

6. Soil Classification/Taxonomy
Second edition –1999
USDA classification system
Soil Survey Staff 1965
Soil Taxonomypublished 1975
11
th
edition -2010

7. U. S. System of Soil Taxonomy
Soils are named, mapped as a geologic entity or
individual
1st taxonomic system began in 1938
12 orders separate all soils
Pedonsare identified to help separate soil orders
(minimum 3.3 ft2, & as deep as roots grow)

8. Units for Soil Classification
Pedon–smallestthree-dimensionalunitthatdisplays
thefullrangeofproperties/characteristicof
agivensoil.(1-10m
2
ofarea)
-thefundamentalunitofsoilclassification
Polypedon–groupofcloselyassociatedpedonsinthefield
SoilSeries–classofsoilsworld-widewhichshareacommon
suiteofsoilprofileproperties

9. Soil Taxonomy
1.Diagnostic Epipedons
2.Diagnostic Subsurface horizons
3.Moisture Regimes
4.Temperature Regimes

10. Soil Taxonomy
Soilsareclassified
intosixcategories
based on
diagnostic
characteristics
Thelastcategory
willplacethesoils
intooneofthe12
SoilOrders.

11. Order
Suborder
Great group
Sub group
Family
Series
12
19,000
Soil Taxonomy Hierarchy
63
250
1400
8000
Kingdom
Phylum
Class
Order
Family
Genus
Species

12. Orders –common ending ‘sol’
Highest and most general soil
classification system (similar
to the phylum in plant
taxonomy)
Based on conditions under
which the soil developed
Fine-loamy mixed, super active, mesicAquic Argiudolls
Order
oll= Mollisols

13. U. S. System of Soil Taxonomy
Order
Most general category
1.Histosols
Organic soils
2.Entisols
Undeveloped soils
3.Inceptisols
Slightly developed
4.Andisols
Volcanic material
5.Vertisols
Swelling-clay

14. U. S. System of Soil Taxonomy
6.Gellisols
Must have permafrost in the top 6’
7.Mollisols
Most extensive soils in the U.S.
Naturally fertile, slightly leached
Can be semiarid to subhumid climates
8.Alfisols
Fertile in favorable moisture conditions
Usually very productive
9.Ultisols
Leached, acidic
Moderate to low fertility

15. U. S. System of Soil Taxonomy
10.Aridisols
Arid-region soils
Can be very productive
11.Oxisols
Hot, wet tropics
Conducive to year-round plant growth
12.Spodosols
Found mostly in cool climates
Poorest soils for cultivation
Must have lime & fertilization to grow crops
Properties that prevent its classification as typic or an
intergrade to another category

16. Suborders
Groupedbysimilaritiesinsoil
formationsuchas
wetter/dryersoil,colder/warmersoil,
dominatingeffectsofchemicalortextural
featuresetc.
Fine-loamy mixed, super active, mesicAquicArgiudolls
Sub
Order
Order
Ud = Udic Moisture

17. Great Groups
Based on differences between
soil horizons & Soil features
Accumulated clay, iron,
humus, hard pans/cement
layers
Fine-loamy mixed, superactive, mesicAquicArgiudolls
Great
Group
Sub
Order
Order
Argi = Clay
accumulation

18. Sub Groups –consists name of the great group
modified by one or more adjectives
Describes a profile characteristic,
wetness, sand etc.
Three kinds of subgroups
Represent the central (typic)
concept of the soil group
Properties that intergrade
towards other groups, etc.
Great
Group
Fine-loamy mixed, super active, mesicAquicArgiudolls
Sub
Group
Sub
Order
Order
Aquic = wet soil

19. Family –indicates particle size class, mineralogy
Basedonsoilpropertiesthataffectmanagement
androotpenetration,suchastexture,temperature,
anddepth
Behaviorofsoilswhenusedfor
engineering
Importantsoilproperties: texture,
mineralogy,pH,avg.soiltemp,moisture,
permeability,thicknessofhorizons,
structure,consistency
Great
Group
Fine-loamy, mixed, super active, mesic Aquic Argiudolls
Family
Sub
Group
Sub
Order
Order
Texture, clay minerals, CEC, temp,

20. Series = Le Sueur (18000 series)
Namedfromthetownorwherethesoilwasfirst
recognized
Typicallynamedaftersomethinglocal(nameof
river,town,area,person,landscapefeaturenear
whereitisfirstrecognized)
Differentiatedonthebasisofobservable&
mappablesoilcharacteristics
Great
Group
Fine-loamy mixed, superactive, mesic Aquic Argiudolls
Family
Sub
Group
Sub
Order
Order

21. Diagnostics Horizons-
Used to place soils into one of the 12 Soil Orders
Surface
(9 Epipedon)
Mollic
Umbric
Histic
Ochric
Anthropic
Plaggen
Melanic
Folistic
Grossarenic
Subsurface
(19)
•Argillic
•Natric
•Spodic
•Oxic
•Cambic
•None

22. Soil Taxonomy-Diagnostic Surface Horizons
(Epipedons-9)
1.MollicEpipedon-thick,dark,soft,
surfacelayer.
Characteristics
MandatoryforMollisols
Thick-greaterthan18-25cm
Highbasesaturation>50%;
Mineralsoil
Ca
++
ionscommon
OrganicCarbon>0.6%
Structurestronglydeveloped

23. 2.Umbric Epipedon
•Meets all criteria of the Mollic epipedon,
except base saturation < 50%
•Mountainous or hilly regions
•Chemicallydifferent than Mollic
•Moist, acidic soils where OM
decomposition slowed due to high water
table or cold temperatures

24. 3. OchricEpipedon
Mollic
Umbric
Ochric = pale
Value = >5.5 (dry) , >3.5 (moist)
low in O.M (<1.0%)
Structure = hard, massive when dry
•Extremely common forested and dry
soils

25. 4.Histic Epipedon
•MandatoryforHistosol
•Formedinwetareas-water
saturatedfor>30consecutive
days
•Organicmaterialsdominate
>20to35%(organichorizon)
•Black to dark brown
•Low bulk density
•20-30 cm thick

26. 5.Melanic Epipedon
•SimilarinpropertiestoMollic
•Formedinvolcanicash
•Lightweight,Fluffy
•Propertiesseenintop30cm
•Melanicindex1.7
•OM>6%

27. 6.Anthropic Epipedon
•Resembles Mollic but dry
(color, OM.)
•Use by humans
•Shells and bones
•Water from humans
•high in phosphorous
(due to long-term
agriculture or human activity)

28. 7.Plaggen Epipedon
•Producedbylong-term(100syrs.)manuring
•Old,human-madesurfacehorizonupto50cm
•AbsentinU.S.systemofclassification.

29. 8.Folistic Epipedon (folia –leaf)
•Saturated for <30 days
•OM : 8-16% or more depending on
clay content of 0-60%
9.Grossarenic Epipedon
•Sandy texture
•>100cm thick

30. Diagnostic Surface Horizons
Epipedons
Mollic
Umbric
Ochric
Histic
Melanic
Plaggen
Anthropic
Very common
Human-derived
“specialized”

31. Vegetation
established
O.M. accumulation
time
Organic Matter Accumulation
Histic
Mollic, Umbric
ochric
Parent
material
t
max= 3000 yrs

32. Comparison of Epipedons
Ochric Histic
Mollic
Umbric
thinner
lighter
color
more
organic
matter
low base
saturation

33. Diagnostic Subsurface Horizons
(Endopedons -19)
Albic
Argillic
Spodic
Oxic
Cambic
Kandic
Sombric
Sulfuric
Spodic
Natric
Agric
Calcic
Gypsic
Salic
Duripan
Fragipan
Placic
Petrocalcic
Petrogypsic
Sub-Horizon Designations

34. Diagnostic Subsurface Horizons
Albic(white) endopedon
•Light-colored(Value>6moist,Value>4(dry)
•Elluvial(Emasterhorizon*)
•Lowinclay,FeandAloxides
•Generallysandytextured
•Lowchemicalreactivity(lowCEC)
•TypicallyoverliesBhorBthorizons
albic
*not all E horizons are albichorizons

35. Argillic Horizon (argilla= white clay)
•Requiredfor Alfisols, Ultisols
•Illuvial accumulation of silicate clays
•Illuvial based on overlying horizon
•clay-enriched Bt horizons
•Clay bridges, clay coatings
•Indicates a stable surface
Argillic Horizon Kandic Horizon
Activity of ClaysHigh Low
Illuviation of clayNecessary Not Necessary

36. NatricEndopedon
sameasargillic,buthaseither:
(1)prisms/columnsinupperpart,
or
(2)highNacontent
Bn or Btn

37. Spodic Horizon (spodos = wood ash)
Spodic-illuvialaccumulationof
oxidesofAlandFe(sesquioxides)
andOM.
redordarkredcolor-onlyfound
inacidsandysoils,withhigh
rainfall(value,chroma<3)
generallyfoundbelowEhorizon.
ContainsaBhsorBshorizon
Lowbasesaturation(acidic)
Formesunderhumidacid
conditions
Oi
E
Bhs
Bs
C

38. Oxic horizon (oxide)
•Highly weathered (high temp. high rainfall)
•Intensively weathered horizon (B
o)
-High in Fe, Al oxides
-High in low-activity clays (Kaolinite < smectite < vermiculite)
activity
Requiredfor Oxisols
-claymineralsare1:1oroxides
-residualaccumulationofAl,Ti,
FeandMn
-LowpHnotveryfertile
-veryold,stablesurfaces
-tropical/subtropical,wet/dryclimates

39. Natrichorizon-sameas
argillic,buthaseither:
(1)prisms/columnsinupperpart,
or
(2)highNacontent
Cambic-slightlyalteredlayer-
notweatheredenoughtobe
argillic,Bwhorizondesignation
ordevelopmentofcolorandor
structure
NONE -nodiagnostic
subsurfacehorizonpresent
Bn or Btn

40. Comparison of Subsurface Diagnostic
Horizons
Oxic
very
weathered
Spodic Cambic
Argillic
Natric
more Al
and Fe
less
developed
more sodium

41. 12 Soil Orders -Each Order has a diagnostic epipedon and
subsurface horizons –which could be “none”.
WEB SITE for soil orders = www.mines.uidaho.edu/pses/teach_res
Entisol
Inceptisol
Andisols
Spodosols
Mollisols
Alfisols
Ultisols
Oxisols
Aridisols
Vertisols
Histosols
Gelisols

42. SOILS OF INDIA
1.Alluvial soils
2.Black soils
3.Red Soils
4.Laterite Soils
5.Coastal Sands

43. Alluvial Soils –75 mha
Soil formation : parent material -river
alluvium, coastal sands and delta
alluviums
Features: 1.Texture -coarse (near
source) fine texture ( near sea/ delta)
2. mostly alkaline or acidic in reaction
3. rich in P & K but deficient in N & OM
Crops : wheat, rice, sugarcane and other
crops
Constraints:
1. Leaching (sandy) and drainage
2. intensive cultivation –deficiency of S and Zn
3. rising of ground water level
Management :
-Judicious use of irrigation water and fertilizers
-providing drainage facilities

44. Crops:rice,maize,wheat,Sugarcane,
tobacco,jute,oilseeds

45. Crops:cotton,wheat,linseed,
millets,tobacco,oilseeds,rice,
sugarcane
Extent –74 mha
Parent material –Basalt
Semi arid-sub humid
plain topography

46. Crops:Cotton,wheat,rice,
pulses,millets,tobacco,oilseeds
Extent: 70 mha
AP –27.4 mha
Othernames:
redloams,
redearths,
red&yellowsoils
Climate:
hotSemiarid,humid
subtropical

47. Extent: 25 mha
Climate : sub
tropical to tropical ,
higher topography
Constraints:
high permeability,
low AWC, High P-
fixation,
Al & Mn toxicity,
strongly acidic

48. Humuscontentofthesoil
islow,microorganismslike
bacteria,getdestroyeddueto
hightemperature.

49. Coastal Sands
Present all along coast 3 to 12 km away on both east and west
coast
Parent material : Marine sediments
Properties:
1.Deeptoverydeep
2.Groundwaterat2to5mdepth
3.Brackishwater,salineinreaction
4.sandytexturewithlessclaycontent
5.Lightsoils,morepermeability,lowWHC
6.lowOM,lowCECandBasesaturationandless
fertile.
Land use -Doruvu technology water management
Constraints–during cyclone –inundated due to tidal over
flow