Jim Owen, Jr.

Substrate Properties: How to measure and manage them

North Willamette Research andExtension Center

My Approach

NUTRIENTS

ENVIRONMENT IRRIGATION

SUBSTRATE

ContainerContainer

My Approach

NUTRIENTS

ENVIRONMENT IRRIGATION

SUBSTRATEContainerContainer

My Approach

Engineer a substrate to balance water and air content

while providing or retaining plant nutrients

My Approach

SUBSTRATEWater : Air

“There is no one fit”

My Approach

SUBSTRATEWater : Air

SUMMERWater

WINTERAir

Approach

SUBSTRATEWater : Air

SUMMERWater

WINTERAir

My Approach

STABILITY OVER TIME

Optimal air and water characteristics

Decomposition / shrinkage during growing season

Initial vs end of season physical analysis

Supply and/or retain nutrients

Substrate

Total porosity (% volume)Air spaceContainer capacity

• Syn. water holding capacity

Terms

Total porosity (% volume)Air spaceContainer capacity

• Syn. water holding capacity Available water Unavailable water

Terms

Total porosity (% volume)Air spaceContainer capacity

• Syn. water holding capacity Available water Unavailable water

Bulk density (g cm-3)

Terms

Total porosity 50% - 85%Air space 10% - 30%Container capacity 45% - 65%

• Syn. water holding capacity Available water 25%- 30% Unavailable water 25%- 30%

Bulk density0.2 to 0.5 g cm-3

12 to 32 lbs ft-2

Terms

Gravitational waterDrainage water

Hygroscopic waterAdsorbed water

Capillary waterAvailable waterUnavailable water

Terms cont…

adsorbed or hygroscopic water

capillary water

Hillel

AIR : WATERRELATIONSHIP

Will a given substrate have a greater, equal, or less than

container capacity when compared to a field capacity?

Will a given substrate have a greater, equal, or less than container capacity when

compared to a field capacity?

WHY?

Water will not move from small pores (fine texture) to large pores (coarse texture) until small pores are saturated.

Small pores large pores

Small pores (full) large pores

Water movement

X

Sand over clay

Water movement

Oklahoma State University

Sand over clay

Water movement

Oklahoma State University

Clay over sand

Water movement

Oklahoma State University

Clay over sand

Water movement

Oklahoma State University

Moisture Content

Fonteno

Does container shape affect physical properties?

SOLIDS

WATER

AIR TOTAL POROSITY

Effected by container sizeAir space Container capacity

• Available water contentUnaffected by container size

Total PorosityUnavailable water contentBulk density

Physical Properties

SOLIDS

WATER

AIR TOTAL POROSITY

1 2 3Bilderback and Fonteno

29% 29% 29%

SOLIDS

WATER

AIR TOTAL POROSITY

1 2 3Bilderback and Fonteno

29% 29% 29%

SOLIDS

WATER

47% 45% 41%

AIR TOTAL POROSITY

1 2 3Bilderback and Fonteno

29% 29% 29%

SOLIDS

WATER

47% 45% 41%

AIR

24% 26% 30%

TOTAL POROSITY

1 2 3Bilderback and Fonteno

29% 29% 29%

SOLIDS

WATER

47% 45% 41%

AIR

24% 26% 30%

71% 71% 71%

TOTAL POROSITY

1 2 3Bilderback and Fonteno

Particle Size

Particle Size

Capillary Water

Particle SizeStabilityComponents “fit”Fine particles

< 0.5 mm Single component

• ≈ 25% by weightMultiple components

• < 50% by weight

Particle Size

05

10

15

20

25

30

35

40

% w

eigh

of p

artic

les

<

0.5

mm

Fresh PB Aged PB Fresh 8 PB: 1 Sand

Aged 8 PB :1 Sand

Particle Size

0

20

40

60

80

100

0.01 0.1 1 10 100Tension (kPa)

Perc

ent v

olum

e

Peat BarkCoir Perlite

Fonteno

Particle Size

0

20

40

60

80

100

0.01 0.1 1 10 100Tension (kPa)

Perc

ent v

olum

e

Peat BarkCoir Perlite

RAW

Fonteno

Particle Size

0

20

40

60

80

100

0.01 0.1 1 10 100Tension (kPa)

Perc

ent v

olum

e

Peat BarkCoir Perlite

EAWWBC

SUBSTRATE COMPONENTS

Primary ComponentDouglas Fir Bark

Secondary ComponentsPerlitePeatCoir

Tertiary ComponentsMineralsCompost

Northwest Substrate

First, I Digress!

Bark Inventory Management

Bark SupplyCheck interior of inventory piles

Pour thru Saturate media extract

Desired resultspH > 3.8EC < 0.5 mmhos

Bark Supply

Bark Arrives Hot! Steam Haze around pile! Spores

Bark SupplyMoisture Content- By feel or %weight

Bark should not be powder drySmell; Vinegar smell could be trouble;

indicates anaerobic conditionsAcetic acid lowers pH and extracts

saltspH can be as low as 2.3EC can be as high as 2.5 mmhos/ cm

Bark SupplyMycelium

Gray colorGray bandDry pocketsHydrophobioc

Turn and moisten pile

Bark SupplyBe prepared not to immediately use bark

supplies if monitoring suggests problemsDevelop an inventory storage area and

wet and turn piles 2-3 days before useAlways check pH and EC before using

stored suppliesConsider blending old inventory and new

inventory (50:50)

Douglas Fir Bark

Altland

Douglas Fir Bark

AGED FRESH

Altland

Douglas Fir Bark

0%

20%

40%

60%

80%

100%

Con

tain

er V

olum

e

Fresh bark Aged bark Recommendedrange

WaterAirSolid

Buamscha and Altland

Douglas Fir Bark

0%

20%

40%

60%

80%

100%

Con

tain

er V

olum

e

Fresh bark Aged bark Recommendedrange

WaterAirSolid

Water Holding Capacity

27% 37% 45% - 65%

Buamscha and Altland

50% 35% 10% - 30%

Volcanic rockBendMazama – Crater lake

High porosity Water holding capacity ~30%Chemical

SiO2

Neutral pHBase cations and Fe-oxides

Pumice

Buamscha and Altland

Industrial mineral AggregateChemical absorbentFertilizer carrierBarrier clays

Murray, 2000.

Mineral aggregateRaw Clay Selection & Mining

Primary CrusherSecondary Crusher

Dryer(RVM)Mill

Screen

Rotary Kiln(LVM)

Oil-Dri Corporation of America

Bag or Bulk

≤ 800°C ≈ 120°C

Mineral aggregate

Zeolite

Mineral aggregate

Shulze, D.G., 2002. An introduction to soil mineralogy. In: Soil Mineralogy with Environmental Applications SSSA Book Series no. 7.

Mineral AggregateMontmorillonite Palygorskite

Shulze, D.G., 2002. An introduction to soil mineralogy. In: Soil Mineralogy with Environmental Applications SSSA Book Series no. 7.

Amendment

Montmorillonite Palygorskite

Surface Area ≈ 90 m2/gCEC ≈ 100 cmolc kg

Oil-Dri Corporation of America

Clinoptilolite

Surface Area ≈ 40 m2/gCEC ≈ 250 cmolc kg

Surface Area ≈ 120 m2/gCEC ≈ 20 cmolc kg

Amendment

Shulze, D.G., 2002. An introduction to soil mineralogy. In: Soil Mineralogy with Environmental Applications SSSA Book Series no. 7.

HeatingDehydration

Natural Occurring

LowVolatileMaterial

Palygorskite and Zeolite

Amendment

HeatingDehydration

Natural Occurring

LowVolatileMaterial

Shulze, D.G., 2002. An introduction to soil mineralogy. In: Soil Mineralogy with Environmental Applications SSSA Book Series no. 7.

Montmorillonite

PeatCanadian peat

Sphagnum moss peat• 75% Sphagnum species• 90% organic matter

Degree of composition• light > dark > black

British Bryological Society

http://www.mosserlee.com

PeatPhysical

<90% porosityShrink

• Water content• Time

ChemicalpH ≈ 4CEC

Sun Terra

CoirCoir pith

Mesocarp pithy tissueHigh porosityLow Easily Available waterChemical

pH 7CECP and K

Coir

Coir

Sri Lanka and Mexico

Coir

waste product

Coir

Porosity COIR VS PEAT

Surface 41% 12%

Internal 41% 51%

Coir

Porosity COIR VS PEAT

Surface 41% 12%

Internal 41% 51%

Wettability!

CoirFine particle sizeMonitor saltsCa source

Gypsum

Compost

CompostIncrease water holding capacityReproducible?Uniform?Stable?Salt concentration

PoultryMetals

Swine (Zn)

CompostIncrease water holding capacityReproducible?Uniform?Stable?Salt concentration

PoultryMetals

Swine (Zn)

Moisture Content

0

20

40

60

80

100

0.01 0.1 1 10 100Tension (kPa)

Perc

ent v

olum

e

Peat BarkCoir Perlite

RAW

Pine Bark

0%

20%

40%

60%

80%

100%

Con

tain

er V

olum

e

Aged PB PB: 30% Perlite PB: 10% Peat

UnavailableWaterAvailableWaterAir

Solid

Mixtures

37%

Pine Bark

0%

20%

40%

60%

80%

100%

Con

tain

er V

olum

e

Aged PB PB: 30% Perlite PB: 10% Peat

UnavailableWaterAvailableWaterAir

Solid

Mixtures

37%

Inc. Air Space Inc. Available water

Clay amended pine bark

PRACTICALAPPLICATION

Physical PropertiesClay rate

0.25 to 0.85 mm LVM0% to 24% (by vol.)

• 4% incrementsPoromoter15-bar extraction

Clay Rate

0

20

40

60

80

100

0 4 8 12 16 20 24

Vol

ume

(%)

Mineral amendment rate (% vol.)

PorometerResults

Clay Rate

0

20

40

60

80

100

0 4 8 12 16 20 24

Vol

ume

(%)

Mineral amendment rate (% vol.)

Container Capacity

Air space

Clay Rate

0

20

40

60

80

100

0 4 8 12 16 20 24

Vol

ume

(%)

Mineral amendment rate (% vol.)

Container Capacity

Available water

Clay Rate

0

20

40

60

80

100

0 4 8 12 16 20 24

Vol

ume

(%)

Mineral amendment rate (% vol.)

Unavailable water

Available water

Clay Rate

0

20

40

60

80

100

0 4 8 12 16 20 24

Vol

ume

(%)

Mineral amendment rate (% vol.)

Container Capacity

Unavailable water

Air space

Available water

Clay Rate

0

20

40

60

80

100

0 4 8 12 16 20 24

Vol

ume

(%)

Mineral amendment rate (% vol.)

Container Capacity

Unavailable water

Air space

Available water

Normal Range

Clay Rate

0

50

100

150

200

250

300

0 8 12 16 20

Top

dry

mas

s (g

)

Amendment rate (% by vol.)

Clay Rate

0

50

100

150

200

250

300

0 8 12 16 20

Top

dry

mas

s (g

)

Amendment rate (% by vol.)

Max. = 12%

Clay Rate

0

2

4

6

8

10

12

0

0.1

0.2

0.3

0.4

0.5

0 8 12 16 20

Pn (µ

mol

CO

2 m-2

s-1

) gs (µm

ol H2 O

m-2 s

-1)

Amendment rate (% by vol.)

Clay Rate

0

2

4

6

8

10

12

0

0.1

0.2

0.3

0.4

0.5

0 8 12 16 20

Pn (µ

mol

CO

2 m-2

s-1

) gs (µm

ol H2 O

m-2 s

-1)

Amendment rate (% by vol.)

Max. = 11%

Clay Rate

0

0.1

0.2

0.3

0.4

0.5

0

100

200

300

400

500

0 8 12 16 20

g s (µm

ol H

2O m

-2 s

-1)

Water use efficinecy (m

l g-1)

Amendment rate (% by vol.)

Plastic bag method

FIELDQUANTIFICATION

Field QuantificationWhy?

Check Bark supplyExperiment with new componentsAffect of how you pot

Field Quantification

Known container volume

Field Quantification

Fill, pack, remove excess

Field Quantification

Saturate with known volume = total porosity(weight can also be used)

Field Quantification

Drain a known volume = air space

Field Quantification

Container Capacity = total porosity - air space

Field Quantification

Bulk Density = dry weight / container volume

Field QuantificationWhy

Check Bark supplyExperiment with new componentsAffect of how you pot

QUESTIONS