l Soi s
the una ppr eci a ted na tur a l r esour ce
Fr ed M a gdoff D ept. Pl a nt & Soi l Sci ence
You ask me to pl ow the gr ound. Shal l I take a kni fe and tear my mother s br east?
Native American Chief
M any a hi l l si de do the tor r ents fur r ow deepl y, and down to the dar k sea they r ush headl ong fr om the mountai ns, wi th a mi ghtl y r oar , and the ti l l ed fi el ds of men ar e wasted. The Iliad
... for soi l thou a r t a nd unto soi l sha l t thou r etur n.
BookofGenesis
Then God Yahweh for med man out of the soi l of the ear th
BookofGenesis
Soi l + L i fe
Adam fr om H ebr ew wor d for soi l Eve fr om the wor d for l i fe
Ar e you r eal l y made out of soi l ?
Wheredidthefollowingcomefrom: calciuminyourbones phosphorusinbonesandfatsandnucleicacids nitrogeninproteins iron,potassium,magnesium,etc.
Ar e you r eal l y made out of soi l ?
Andwheredidthecarboncomefrom? Fromplantsgrowingonandinsoils andthatfixedatmosphericCO2.
What do pl ants need?
What do pl ants need?
L i ght War mth Car bon di oxi de (CO2) Oxygen (O2) Water Nutr i ents Anchor age
What do pl ants need?
Nutr i ents
C,H,O, N,P,K, Mg,Ca, S,Fe, Cu,Co, Ni,Mn, Mo,B, Zn,Cl
What do soi l s pr ovi de to pl ants?
Oxygen (O2) t o r oot s H elp get r id of CO2 Wat er M ost nut r ient s Anchor age
What el se do SOI L S pr ovi de?
Par ti ti oni ng r ai nfal l (r unoff vs. i nfi l tr ati on)
What el se do SOI L S pr ovi de?
Par ti ti oni ng r ai nfal l (r unoff vs. i nfi l tr ati on) Stor ehouse for Car bon
carbon dioxide (CO2)
(0.04% in the atmosphere)
photosynthesis
respiration instems andleaves
rootrespiration andsoilorganic matter decomposition
cropand animal residues carbonin soil organicmatter
cropharvest
erosion
Fig.4.6Theroleofsoilorganicmatterinthecarbon cycle.
What el se do SOI L S pr ovi de?
Par ti ti oni ng r ai nfal l (r unoff vs. i nfi l tr ati on) Stor ehouse for Car bon Cl eansi ng pol l utants (seepage fi el ds, manur es, sl udges)
Soils ar e a living filt er
As water per col ates thr ough a soi l pathogens may be deacti vated Phosphor us i s r emoved Ni tr ogen i s r emoved Car bon i s r emoved M any har mful chemi cal s r emoved
What el se do SOI L S pr ovi de?
Par ti ti oni ng r ai nfal l (r unoff vs. i nfi l tr ati on) Stor ehouse for Car bon Cl eansi ng pol l utants (seepage fi el ds, manur es, sl udges) Bui l di ng mater i al
What el se do SOI L S pr ovi de?
Par ti ti oni ng r ai nfal l (r unoff vs. i nfi l tr ati on) Stor ehouse for Car bon Cl eansi ng pol l utants (seepage fi el ds, manur es, sl udges) Bui l di ng mater i al Somethi ng to bui l d on (bui l di ngs, r oads)
What ar e soi l s made of?
M i ner al s Or gani c matter Por es (water & ai r )
What ar e soi l s made of? M i ner al s
Or gani c matter Por es (water & ai r )
M i ner al s
SAN D 2mm to 0.02mm diameter small pieces of minerals that are found in rocks such as quartz, feldspars, and amphiboles (alumnosilicates) SI L T 0.02 to 0.002mm diameter minerals similar to sand CL AY <.002mm in diameter and colloidal frequently formed in soils Many types of clays (with different properties) Most clays have plate-like structure contain negative charge (cation exchange
What ar e soi l s made of?
M i ner al s
Or gani c matter
Por es (water & ai r )
Or gani c M atter
L iving Dead Ver y Dead
L iving Plant s have evolved in a dynamic r elat ionship wit h ot her or ganisms Beneficial and har mful Above and in t he soil
plantroots bacteria nematodes fungi mites moles springtails
Living
earthworms
Figure2.1Anematodefeedsonafungus,partofa livingsystemofchecksandbalances. PhotobyHaroldJensen.
spore
Figure3.2Rootheavilyinfectedwithmycorrhizalfungi(noteround sporesattheendofsomehyphae).PhotobySaraWright.
Figure3.2a.Stickysubstance,glomalin, surroundingrootheavilyinfectedwith mycorrhizalfungi.PhotobySaraWright.
e ne rgy flows in dire ct ion of arrows ground be e t le s 8 - 20 mm
1o = first le ve l consume rs 2o = se cond le ve l consume rs 3o = t hird le ve l consume rs 2o - 3o ant 5 -10 mm 2o
ce nt ipe de s 50 mm
pse udoscorpion 1- 2 mm springt ails .5 - 3 mm 2o pre dat ory mit e .5 -1 mm 2o rove be e t le s 10 mm 2o fe at he rwinge d be e t le 1- 2 mm
flat worms 70 -150 mm ne mat ode s prot ozoa .01- .5 mm fly 1- 2 mm
mold mit e be e t le mit e s 1 mm
rot ife ra .1- .5 mm
act inomyce t e s 1o
fungi
1o
bact e ria 1o
sowbug 10 mm ne mat ode s millipe de s 1mm 20 - 80 mm e art hworms 1o 50 -150 mm
be e t le mit e s 1 mm whit e worms 10 - 25 mm land slugs & snails 2 - 25 mm
organic re sidue s
le ngt hs of organisms give n in millime t e rs (25 mm = 1 in)
Figure3.1Soilorganismsandtheirrolesindecomposing residues.ModifiedfromD.L.Dindal,1978.
Dead Freshresiduesin earlystagesof decomposition
Dead Foodsupplyforthe vastnumberof organismsthatlive inthesoil
Figure2.2Partiallydecomposedresidues(thedead) removedfromsoil.Fragmentsofstems,roots,
fungalhyphae,areallreadilyusedbysoilorganisms.
VERYDead Welldecomposed material,humus
Humus Colloidal Hasmanynegativesites (canholdontocationssuch asCa++,Mg++,K+=CEC)
Figure4.5Corngrownin nutrientsolutionwith (right)andwithout(left) humicacids.PhotobyR.
QuickTime and a Photo - JPEG decompressor are needed to see this picture.
Bartlett.
InthisexperimentbyR.Bartlett andYongLee,addinghumicacids toanutrientsolutionincreased thegrowthofbothtomatoesand andbranchingofroots.
What cornandincreasedtheamount ar e soi l s made of?
M i ner al s Or gani c matter
Por es (water & ai r )
organicmatter air minerals Soilwetsup duringrain Soildries down
water
solids
pores
Figure6.1.Distributionofsolidsandporesinsoil.
organicmatter air minerals water Soilwetsup duringrain
solids
pores
organicmatter
minerals
air
Soildries down
water solids pores
smallpore
largepore intermediate pore
Aggregate (crumb) Figure6.3Awellaggregatedsoilhasarangeofpore sizes.Thismediumsizesoilcrumbismadeup ofmanysmallerones.Verylargeporesoccur betweenthemediumsizeaggregates.
Add organic matter
Reduced soilbornediseases, parasiticnematodes
Increasedbiologicalactivity (&diversity)
Aggregation increased
Decomposition
Porestructure Humusandother Nutrients improved growthpromoting released Harmful substances substances Improvedtilth detoxified andwaterstorage
HEALTHYPLANTS
Figure4.1Addingorganicmatterresultsinmanychanges. ModifiedfromDrinkwater&Oshins,1999.
Whatcausessoilstobedifferent fromoneanother?
Whatcausessoilstobedifferent fromoneanother?
parentmaterial
Thematerialfromwhichthe soilderived.Forexample: Lakebottom(muchofChamplain Valleylowlands) Riverfloodplains(alluvial) Windblownmaterial(loess) Rocksinplaceormovedbyglacier
Whatcausessoilstobedifferent fromoneanother?
positioninthetopography
Soilsonslopesarekeptyoung becauseoferosionwhilethoseat thebottomsreceiveextrawater andsedimentsfromupslope.
Whatcausessoilstobedifferent fromoneanother?
Climate
Intensiveweatheringunderhot andhumidconditions. Weatheringandsoil developmentareveryslow underaridconditions.
Whatcausessoilstobedifferent fromoneanother?
vegetation
Grasslandsoilstendtohave muchhigherlevelsoforganic matterandaremorefertilethan soilsdevelopedunderforest.
Whatcausessoilstobedifferent fromoneanother?
time
Ittakestimeforforcesof weatherandinfluenceof vegetationandslopepositionto beexpressed.
Whatcausessoilstobedifferent fromoneanother?
humanactivity
Humanshaveamajorinfluence onmanyoftheworldssoils. (Acceleratederosion,depletion ofsoilnutrientsbyintensive cropping,installationoftile drainage,etc.)
Tama soils were formed in silty material, called loess, under tall prairie grasses that have a deep fiberous root system and under relatively humid climate. Grasses have added organic matter, producing a relatively thick, dark surface layer. Erosion is a continuing problem with these soils.
The Paxton series consists of very deep, well drained soils on glacial till uplands. The dense subsurface till is characteristic of Paxton soils. Permeability is moderate in the surface layer and subsoil and slow or very slow in the substratum. Available water capacity is high. Very strongly acid to moderately acid. A seasonal high water table is at a depth of 1.5 to 2.5 feet.
Tifton soils occur throughout the Southern Coastal Plain in Georgia. Tifton soils formed in loamy sediments of marine origin. They are among the most important agricultural soils in the State. Cotton, peanuts, soybeans, and corn are the principal crops grown on these soils.
Drummer soils consists of very deep, poorly drained soils that formed in 40 to 60 in. of loess or other silty material and...