soil remediation re vegetation 6-11

8/6/2019 Soil Remediation Re Vegetation 6-11

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Revegetation of Former Hydrocarbon

and Brine Impacted Soils

Kerry Sublette(918)691-0639

[email protected]


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An issue particular to hydrocarbonimpacted soils: hydrophobicity

Hydrophobicity is caused by the coating of soilparticles with hydrophobic or water repelling

organic matter

Water drops on

hydrophobicsoil


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Hydrophobicity can inhibit revegetation

Li et al. (1997) showed that hydrocarbon impactedsoils failed to support healthy plant growthbecause the soil would not hold water (not because

of any toxicity)Contaminated soil contained 4% TPHBioremediated soil contained 2% TPHControl soil with no hydrocarbon impactAll soils received the same watering protocol withcollection of leachate

Li et al., Plant and Soil, 192, 219-226 (1997)


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Leachatecollected andmeasured

Control4%TPH

2% TPHBiorem


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Barley Growth in Crude Oil Impacted Soil

Shoot dry massRoot dry mass

Yield

Growth Parameter

0

20

40

60

80

100

120

140

gdrywt.

Control Soil4% TPH2% TPH Bio


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When is hydrophobicity likely to be aproblem?

Roy et al. (2003), in a study of a old weathered oil-impacted sites in Alberta, reported thathydrophobicity was associated with some, but not all,

crude oil spill sitesHydrophobicity is probably a product of acombination of circumstances including:

properties of the crude oil (greater proportions of heaviesand waxy hydrocarbons)

dryness of the soil at the time of first contact withhydrocarbonprolonged exposure to hot dry weather and ultravioletlight

Roy et al., J. Environmental Quality, 32, 583-590 (2003)


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An example of UV-induced chemicalreactions

These photo-induced reactions increase the

likelihood of strong interactions betweenhydrocarbons and mineral particles and SOM.Result is:

Increase in hydrophobicity

Decrease in apparent TPH (poor extraction of

photoproducts)


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How do we measure hydrophobicity?

Molarity of Ethanol Droplet (MED) testHand sieve soil to a fineness of < 1 mm removingany rock or plant fragments

Dry the soil at 105 oC for 24 hrsTransfer soil to a shallow container and levelthe soil gentlyUse a medicine dropper to gently apply drops ofwater with increasing concentrations of ethanolto the soil surface, each time assessing theamount of time required for total absorptionThe MED is the molarity of the leastconcentrated ethanol solution that is absorbedin under 10 sec

Reference


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Preparation of ethanol solutions

Molarity (M) mL Vodka* Molarity (M) mL Vodka*

0 0 3.2 18.70.2 1.2 3.4 19.8

0.4 2.3 3.6 21.0

0.6 3.5 3.8 22.2

0.8 4.7 4.0 23.3

1.0 5.8 4.2 24.5

1.2 7.0 4.4 25.7

1.4 8.2 4.6 26.8

1.6 9.3 4.8 28.0

1.8 10.5 5.0 29.2

2.0 11.7 5.2 30.3

2.2 12.8 5.4 31.5

2.4 14.0 5.6 32.6

2.6 15.2 5.8 33.8

2.8 16.3 6.0 35.03.0 17.5 6.2 36.1

*Dilute theindicated volume of100 proof vodka toa total of 50 mLwith distilledwater.

Reference


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What can we do about hydrophobicity?

Hydrophobicity is counteracted byhydrophilic organic matter (hay orcomposted manure, for example) andhydrogels

Increases water holding capacity ofthe soilIncreases contact of water with

hydrophobic soil particles makingthem more likely to wet


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The power of hydrogels


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Growth of Ryegrass in Remediated Crude Oil Impacted Soil

0

100

200

300

400

500

600

700

800

900

Soil only Compost RestorNhance

PlantBiom

ass(mg)

CompostSoil only


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Hydrogels field testInitiated July 2008

Randomized block design with at least triplicate treatments8 ft by 8 ft plots9 gal of 42 API crude oil applied and tilled inAmendments for treatments applied and plots re-tilledEquivalent of one inch rainfall applied at startup

Reapplication of amendments at 30 and 60 daysTreatments

HayFertilizerHay + FertilizerCompost + Hydrogels (BioNhance)Compost + Hydrogels + Hay

Compost + Hydrogels + FertilizerCompost + Hydrogels + Hay + FertilizerNone

AnalysisTPH DRO at 0, 30, and 60 daysPlant above ground biomass and percent coverage in Spring 2009


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BNF

F+BNF+H

F+H+BNH

H+BNN

0

20004000

6000

8000

10000

12000

14000

16000

18000

20000

22000

24000

26000

28000

TPHDRO

(mg/kg)

t=0 dayst=30 dayst=60 days

BN = BioNhanceF=fertilizer, H=hay, N=no treatment

Pl b d b


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Plant aboveground biomassSpring 2009

H+BNF+H

HF+BN

F+H+BNN

FBN

Treatment

0

50

100

150

200

250

300

350

400

WtBiomass(g/m2)

F=fertilizer, H=hay, N=no treatmentBN = BioNhance

Pl


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Plant coverSpring 2009

H+BNF+H

HF+BN

F+H+BNN

FBN

Treatment

0

10

20

30

40

50

60

70

80

90

%Cover

F=fertilizer, H=hay, N=no treatmentBN = BioNhance


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No treatment


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Fertilizer only


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Hay + BioNhance

H d f tili


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Hay and fertilizer


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BioNhance + hay and fertilizer


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Revegetation of former brine

impacted soils

The ultimate goal of the brineremediation process

Even if you dig and haul you still have torevegetate


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Revegetation

Natural revegetation?Requires adequate moisture

Rainfall relative to evaporation potential

Requires desired vegetation immediately adjacent to siteIf and when the desired vegetation makes up > 20% ofthe plant canopy cover then natural revegetation with thedesired plant community is possibleWeed management strategies may be required to give

the desired plants a foothold in the siteFrequent monitoringHand pulling of weedsSpot treatment with herbicidesTransplanting of desired vegetation


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Correcting weed infestations

Till site in late fall to encourage maximum germination ofweed seedsA few weeks later apply a non-selective herbicide to killnewly emerging weeds

Following herbicide treatment plant seeds of fall dormantgrassesThe following spring the remaining weed seeds and seededgrasses should emerge with adequate moisture; if grassseedlings survive to midsummer apply a broadleaf herbicideContact local experts for herbicide recommendations andrates specific to your site conditions

Reference


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Reseeding for revegetation

Establish goals in consultation withlandowner and regulator

Restore forage crops?Restore agricultural productivity?

Restore native plant community?

Quick revegetation for erosion control?

Halophytes?


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Reseeding a remediated site, replacementsoil, or other restoration site

Assess the overall quality of the soilPrimary and secondary plant nutrients

Use an ag lab to provide recommendations for specific plantcommunity desired

Bulk density (g dry soil/cm3)Ideal: 1.4Acceptable: 1.2 1.6

Soil textureMatch plants with soil texture

Organic matter

Ideal: > 3%Acceptable: > 2%pH

Ideal: 6.5 - 7.5Acceptable: 5.5 8.5


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Use an ag lab to provide recommendations for specificplant community desired



Organic matter




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Reference


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Reference


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Organic matter




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The bulk soil density is the weight of ovendry soil/volume of the soil before drying

Highbulk soildensity

Low bulksoildensity


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Bulk soil

density

Low Medium High


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The effects of soil compaction maypersist for decades

Historic bison wallow

(from the 19thcentury) in tallgrassprairie in Oklahoma

Id l il b lk d i i d h


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Ideal soil bulk densities and root growthlimiting bulk densities for soils of

different textures

Soil texture

Idealbulkdensities

Bulkdensitiesthat mayaffect root

growth

Bulk densitiesthat mayrestrict root

growth

g/cm3

Source: generalized from USDA-NRCS soil quality test kit guide.

Sand, loamy sand 1.80

Sandy loam, loam, sandy clayloam, clay loam, silt, siltloam, silty clay loam

1.75

Sandy clay, silty clay, clay 1.60


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Measuring bulk soil density

Remove vegetation from the soil surface

Push a pre-weighed sampling can of known volume into the soil.If it is difficult to push into the soil, place a piece of woodover the can and hit the wood with a hammer. If necessarywet the soil to make it easier to drive into the ground. Drivethe sampling can into the ground until soil just starts to comeout of the small hole in the bottom of the can.


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Measuring bulk soil density

Using a trowel or shovel dig around the can in order toremove it from the soil

Trim the soil from the top of the can and around the edges

of the can so that the volume of the soil is the same as thevolume of the can; cover the can with a lid and label and shipto ag lab


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Reducing bulk soil density

Ripping and secondary tillage*Incorporation of organic matter (compost

and biodegradable organic matter)*Limit access to livestockKeep vehicles off the siteWith time natural mechanisms of

decreasing bulk soil density:Freeze-thaw cyclesActions of soil animals

*If revegetation efforts immediately follow successful

remediation these steps may be unnecessary.


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Organic matterIdeal: > 3%Acceptable: > 2%

pHIdeal: 6.5 - 7.5Acceptable: 5.5 8.5

What kind of soil do you have?


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Sandy Loam Clay

Wet clay is verysticky; easilyformed into longribbons

Does not feelgritty;floury feel;smooth;wet silt does

not exhibitstickiness

Feels gritty;

non-cohesive

does not sticktogether in amass unless it

is very wet.

What kind of soil do you have?

Can bring in


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Can bring intopsoil toimprove soil

texture


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pHIdeal: 6.5 - 7.5Acceptable: 5.5 8.5


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Organic richtop soil


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Improve soil organic


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Improve soil organicmatter content bytilling in compost andbiodegradable organic

matter; rebuildingdeposits of stableorganic matter is alongterm process.


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pHIdeal: 6.5 - 7.5Acceptable: 5.5 8.5Match plants with soil pH


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pH


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pH affects nutrient availability


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Measuring soil pH

Remember pH of soil is measured by mixingsoil with distilled water and measuring thepH of the water with

pH paperGarden pH kitspH meters
http://images.google.com/imgres?imgurl=http://www.bio-world.com/images/061036.jpg&imgrefurl=http://www.2dgel.com/MoreInfo.asp?ItemCode=061036&h=350&w=350&sz=8&hl=en&start=104&tbnid=6dmZfvM6N5K3DM:&tbnh=120&tbnw=120&prev=/images?q=pH+paper&start=100&ndsp=20&svnum=10&hl=en&sa=N


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Adjusting pH

Neutralizing acidity (to raise pH):Ag lime- dolomite or calcitic limestone crushed

and ground to a specified finenessCalcitic limestone crystalline calciumcarbonate (CaCO3)

Dolomite mixture of calcium carbonate and

magnesium carbonate


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Adjusting pH, cont.

Increasing acidity (to lower pH):Elemental sulfurAluminum sulfate [Al

2

(SO4

)3

]Ferrous sulfate (FeSO4)

Get help from your local ag lab

********************************Note: It is usually better to usespecies adapted to site pH insteadof altering pH especially if thesurrounding area has similar pH


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Seedbed preparation

Soil sufficiently firm toprovide a stablefoundation for roots butporous enough to allow forgood root penetration

Soil loose enough to

allow emergence;shallow enough to allowseedling to emergebefore running out ofenergy

Organic matter toretain moisture


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Seedbed preparation

Primary tillageMost aggressive tillage

Cuts and shatters soil

Buries applied organic matterLeaves rough surface

Secondary tillageFollows primary tillage

Normally shallower working depthProvide additional soil pulverization

Large clods may result in seeds being buried too deep

Level soil surface

Control weeds


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Primary tillage implements


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Field after primary tillage


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Secondary tillage


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Field after secondary tillage

A id i il ti hil


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Field capacity

Avoid excessive soil compaction whilepreparing the seedbed


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Seedbed preparation, cont.

During secondary tillage incorporate any necessarysoil amendments

Topsoil, if needed

Organic matterIn arid and semiarid areas use compostsupplemented with hydrogels captures andholds water

Recommended by USDA Dept. of Agricultural

ResearchFertilizers


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An activating rainfall is neededwith most soil amendments


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The power of hydrogels


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Growth of Ryegrass in Remediated Brine-

Impacted Soil

0

100

200

300

400

500

600

700

800

900

1000

Soil only Compost RestorNhance

Plan

tBiomass(

mg)

Fresh Cow Manure Composted Cow Manure4


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pWet with strong odor Earthy smell1

Moist-dry

High nutrient concentrations Low nutrient concentrations1-3% N, 0.5-1% P2O5, 1-2% K2O(Releases about 10% of itsnutrients per year)

High tendency to burn2 No burning, safe fertilizer

High salinity Usually much lower salinity3

Weed seeds and pathogens Weed seeds and pathogens killedby composting

Biodegradation in soil tends todeplete oxygen

No negative effect on soil gasoxygen

1If it smells of ammonia its not done yet.

2Must let fresh manure age 60-90 days to prevent burning.

3Check salinity before use. Make a paste with distilled water and

measure EC. If EC < 10 mmhos/cm its OK to use if you till it in 6-8 inches.

4Density 15-25 lbs/ft3 or 400-675 lbs/yd3 dry; X 2 moist


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After secondary tillage light packing of the soilprovides a firm but penetrable seedbed

Seedbed too soft


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Is this seedbed too soft?


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Roughing the surfacebefore seeding createssafe sites for seeds andcollect moisture

Light chaining afterbroadcasting seedingfacilitates good contact ofthe seed with soil

Overlay with a thin layer ofsoil/compost


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In areas that are very hot and windy plant a stubble crop the yearbefore seeding with the desired vegetation (use a sterile annualcool season grass)

The next season rough the surface by light raking, sow seeds and

pack lightlyStubble crop provides shade and wind protection for new seedlings


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What to seed?

Depends on management objectivesForage crops

Native vegetationQuick growing species for erosion control

HalophytesGet advice from local

soil conservation districtoffice about species native

to your area


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Regardless of objective

Choose plants that are adapted to soil, climate,elevation, and topography of the area top be restoredImportant to know origin of seedsSeeds should originate from sources from within 200miles N and S and 100 miles E and WUse certified named varietiesMixtures are preferred over single species

Especially different rooting depthsMost efficient use of moisture and nutrients

Use seed of known qualityKnow germination and purity of seedPublished seeding rates are based on pure live seeds(PLS)

%PLS = % purity X % germination

Go to http://plants.usda.gov to get


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p //p . .g gplant distributions by state

This one is fortall wheatgrass.In the web siteyou click on astate and youget thedistribution ofthe plant bycounty in thatstate.


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When to seed?

If you are planning a spring planting, beginseedbed preparation in the fall prior to plantingthe following spring.

Preparation of the site in the fall will damage theroot systems of perennial weeds and expose themto freezing temperatures and the dehydratingaction of winter winds.

In the following spring, the ground should beworked at a shallow depth (secondary tillage) atleast twice to break up clods and eliminate annualweeds.


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How to seed?

Broadcast seeding must be done on loose, roughened soil,seeding is followed by chainingSeeding rates are typically 20-50 seeds/ft2
http://images.google.com/imgres?imgurl=http://www.oaksmeadow.co.uk/uploads/images_products/156.jpg&imgrefurl=http://www.oaksmeadow.co.uk/prodtype.asp?CAT_ID=98&usg=__APWOautAXyhOKwYRjxAGTpO5fWU=&h=140&w=140&sz=7&hl=en&start=131&tbnid=CEpzZ4nuvehOKM:&tbnh=93&tbnw=93&prev=/images?q=seed+broadcasting&gbv=2&ndsp=20&hl=en&sa=N&start=120


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How to seed?

DepthSeeds have stored energy,sprout must break thesurface and produce leavesbefore getting energy fromthe sun. If the seed isplanted too deep the sproutcant make it to the surfaceGeneral rule of thumb plant seeds at a depth 4-7 Xthe diameter of the seed

With a mixture baseplanting depth on thediameter of the smallestseedAvg - inch


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Common causes of planting and


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Common causes of planting andemergence problems

Insufficient moistureSeedbed too hard or too looseOld seeds, dead before planting or had low vigor.

Too few seeds were planted.Seeds were planted too deep.Seeds were not uniformly distributedSeeds were planted too shallow and dug up bybirds or moved by insects.Sowing occurred too long after cultivation allowingweeds to establish and compete with cropseedlings for resources.Heavy rain fell after sowing and the soil surfacecrusted.

Management of revegetation sites


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g g

If natural precipitation is inadequate must waterto establish seedlings!Water only until plants are established, if wellmatched to the local climate they will persist withnormal rainfallWatch for drought stress during this period ofestablishment, monitor soil moistureProtect the site from compaction by livestock

Monitor for signs of nutrient deficiencies in plants


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Management of revegetation sites

Watch for

Foraging by wildlife

Erosion

Areas of revegetation failure

Nutrient management is especially importantwhen gypsum has been used in remediation ofbrine spills!

Poorly prepared fields will cause


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Poorly prepared fields will causemanagement problems in revegetation

Symptoms include:Poor plant establishmentExcessive pest / weed burdens

Uneven plant growth and maturityPoor water use efficiency

You reap what you sow


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Recent revegetation project


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Incorporating

amendments duringsecondary tillage inamendments


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Recent revegetation project

Firming the seedbed


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4 weeks later


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h l f d l l l


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Mycorrhizal fungi and plant available P

Soil P will typically move only about 0.1 in, so plantroots must continually grow into new areas to get P

Mycorrhizal fungi act as extension of plant roots

to increase P uptake -fungi get sugars from plants

d h l f


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Introducing mycorrhizal fungi

Inocula of mycorrhizal fungi are availablecommercially. As your county ag extension serviceif the vegetation you desire can benefit from

mycorrhizal fungi.Collect top litter from surrounding weed-freelandscape and work into top soil.

A stubble crop also captures wind borne spores.

N l


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Nurse plants

Shrubs as nurse plants (over story plants)Increases water available by moistureinterception

Enhance soil fertility

Reduce evaporation

Improves soil structure

Increases nutrient cyclingAdds organic matter from litter


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Element mobility and deficiency symptoms


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Over-all stunted plant and apoorly developed root system.Can cause purple or reddish

color associated with theaccumulation of sugars.Difficult to detect in field.

Mobile within plants:lower leaves showdeficiency first.

Phosphorus

Stunted, slow growing, chlorotic

plants.Reduced yield.Plants more susceptible toweather stress and disease.Some crops may mature earlier.

Mobile within plants:lower leaves showchlorosis first.

Nitrogen

Deficiency Symptoms andOccurrence

MobilityEssentialElement

Iowa State Extension

Iowa State Extension



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Commonly causes scorching or

firing along leaf margins.Deficient plants grow slowly,have poorly-developed rootsystems, weak stalks; lodging iscommon.Seed and fruit are small andshriveled.Plants possess low resistance todisease.Deficiencies most common onacid sandy soils and soils that

have received large applicationsof Ca and/or Mg.

Mobile withinplants: lowerleaves showdeficiency first.

Potassium



Univ. of Minnesota Extension



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Leaves show a yellowish, bronzeor reddish color while leaf veinsremain green.

Mobile within plants:lower leaves showdeficiency first.

Magnesium

Poor root growth: Ca deficientroots often turn black and rot.Failure of terminal buds ofshoots and apical tips of roots todevelop, causing plant growth tocease.

Most often occurs on very acidsoils where Ca levels are low.Other deficiencies usually limitgrowth before Ca deficiency.

Not mobile withinplants: upper leavesand the growing pointshow deficiencysymptoms first.

Calcium



Aarhus University

Clemson University

http://images.google.com/imgres?imgurl=http://www.soils.wisc.edu/courses/soils326/mg_corn.jpg&imgrefurl=http://www.soils.wisc.edu/courses/soils326/magnesium.htm&h=382&w=401&sz=37&hl=en&start=46&tbnid=5IdpNISWECIaBM:&tbnh=118&tbnw=124&prev=/images?q=magnesium+deficiency&start=40&gbv=2&ndsp=20&svnum=10&hl=en&sa=N


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Reduced leaf size anddeformation of new leaves.Interveinal chlorosis ifdeficiency is severe.May cause distorted stems.Related to flower and or fruitabortion, poor grain fill, andstunted growth.May occur on very acid, sandy-textured soils or alkaline soils.

Not mobile withinplants: upperleaves and thegrowing point show

deficiencysymptoms first.

Boron

Chlorosis of the longer leaves.If deficiency is severe, entireplant can be chlorotic andstunted.Symptoms resemble those of Ndeficiency; can lead to incorrect

diagnoses.

Somewhat mobilewithin plants butupper leaves tendto show deficiencyfirst.

Sulfur



NC State Extension

North Central Regional

Committee on Non-conventional

Soil Additives



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Interveinal chlorosis thatprogresses over the entire leaf.With severe deficiencies, leavesturn entirely white.Contributing factors includeimbalance with other metals,excessive soil P levels, high soilpH, wet, and cold soils.

Not mobile withinplants: upper leavesshow deficiencysymptoms first.

Iron

Reduced leaf size.Uniformly pale yellow leaves.Leaves may lack turgor and maydevelop a bluish-green cast,become chlorotic and curl.Flower production fails.

Organic soils are most likely tobe Cu deficient.

Not mobile withinplants: upper leavesand the growingpoint showdeficiency symptomsfirst.

Copper



Ontario Ministry of Agriculture,

Food, and Rural Affairs

North Central Regional Committee

on Non-conventional Soil Additives



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Shortened internodes betweennew leaves.

Death of meristematic tissue.Deformed new leaves.Interveinal chlorosis.Occurs most often on alkaline(high pH) soils or soils with highavailable P levels.

Not mobile withinplants: upper leaves

and the growingpoint showdeficiency symptomsfirst.

Zinc

Interveinal chlorosis.Appearance of brownish-blackspecks.Occurs most often on highorganic matter soils and soilswith neutral to alkaline pH with

low native Mn content.

Not mobile withinplants: upper leavesshow deficiencysymptoms first.

Manganese



Michigan State University

Extension

University of Minnesota

Extension



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Symptoms and occurrence are notwell documented.

Mobile withinplants.

Nickel

Causes N deficiency: chloroticleaves and stunted plants.Occurs in areas with soilsdeficient in native Co.

Used by symbioticN-fixing bacteriain root nodules.

Cobalt

Chlorosis in upper leaves.Overall wilting of the plants.Deficiencies may occur in welldrained soils under high rainfall.

Mobile withinplant, butdeficiencysymptoms usuallyappear on theupper leaves first.

Chlorine

Interveinal chlorosis.Wilting.Marginal necrosis of upper leaves.Occurs principally on very acidsoils, since Mo becomes lessavailable with low pH.

Not mobile withinplants: upperleaves showdeficiencysymptoms first.

Molybdenum



R f


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Reference

Weeds - biological indicators of the


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grestoration of soil health and fertility

During revegetation pay attention to the weeds that pop upThe weeds that grow on your site can signal adverse growingconditions in the soil such as:

Too little water

Too much waterLow NHigh NToo much shadeCompactionLow pH

General low fertilitySend a cutting of the weed to your county extension officefor identification and recommendations

Barnyard grass poor drainage

Example


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Barnyard grass-poor drainage

Birdsfoot trefoil drought low nitrogen

Example


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Birdsfoot trefoil-drought, low nitrogen

Prostrate knotweed compaction

Example


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Prostrate knotweed-compaction

Monitoring overall soil health


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g

Organisms consume other

organisms and excrete inorganicwastes.

Inorganic nutrientsare usable byplants, and aremobile in soil.

Organic nutrientsare stored in soilorganisms andorganic matter.

Organisms take upand retain nutrients

as they grow.

Earthworms as indicators and eco-engineers


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g

Vertical burrows


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Earthworm burrow


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Earthworm burrow

Earthworm burrow opening


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Earthworm burrow opening

Debris pile

Burrowopening

Earthworm casts


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Earthworm casts

Earthworms bury litter


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soil remediation re vegetation 6-11

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