Amendments that improve water retention

Jim Owen, Jr., Stuart Warren, Ted Bilderback, Dean Hesterberg, Alison Prehn, and Joseph Albano

NC STATE UNIVERSITY

The Team

Problem

Low input efficienciesWater 30% to 80%N and P 30% to 60%

Water availability and use

Tyler et al., 1996, Lea-Cox and Ristvey, 2003; Warren and Bilderback, 2005

Approach

NUTRIENTS

ENVIRONM

ENT IRRIGATION

SUBSTRATE

ContainerContainer

Approach

NUTRIENTS

ENVIRONM

ENT IRRIGATION

SUBSTRATE

ContainerContainer

Objective

To engineer a pine bark-based soilless substrate that increased water and nutrient efficiency in containerized nursery crop production

Amendment

Mineral aggregateChemical absorbentFertilizer carrierBarrier clays

IndustrialUniformReproducible

Murray, 2000.

Amendment

Raw 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

4 Years of Research

ExperimentsClay processingClay rateReduced Water

Application Rate

Water Buffering Capacity

4 Years of ResearchMethods

RCBDSkogholm Cotoneaster14 L container (5 gal)Maintained desired LFDependent variables

• Shoot and root dry weight• Net photosynthesis • Stomatal conductance• Water use • Leachate

Water and nutrient (N & P) budgets

Clay Processing

Pine bark-based substratesIndustrial Mineral Aggregate

• 8% Clay (by vol.)

• Particle Size• 0.25 to 0.85 mm• 0.85 to 4.75 mm

Industry Representative Substrate• 11% Sand (by vol.)

Clay Processing

WaterParticle size

• 0.85 to 4.75 mm• 12% (20 L) decrease

• 0.25 to 0.85 mm• 18% (31L) decrease

• Increased WUE (132 mL g-1)

107,000 gallons of water saved per growing acre while maximizing growth

24 - 48

Clay Rate

Clay Rate Physical Properties

0

20

40

60

80

100

0 4 8 12 16 20 24

Vol

um

e (

%)

Mineral amendment rate (% vol.)

Air space

Available water

Normal Range

Clay Rate Physical Properties

0

20

40

60

80

100

0 4 8 12 16 20 24

Vol

um

e (

%)

Mineral amendment rate (% vol.)

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.)

Max. = 11%

Y = 0.6x2 + 13.3x + 247.0 R2 = 0.76

Clay Rate

Clay rate (% vol.) 10% to 12%

• Plant growth• Net photosynthesis• Stomatal conductance• Use efficiency

• Water• Phosphorus

Reduced Water Application

Reduced Water Application

How Low Can You Go!

Reduced Water Application

Amendment (11% by vol.)0.25 to 0.85 mm LVMWashed, builders sand

Leaching fraction0.2 or 0.1

Reduced Water Application

0

20

40

60

80

100

120

0 20 40 60 80 100 120

Clay 0.10 LFClay 0.20 LF

Cum

ulat

ive

influ

ent

(L)

Treatment

Day after initiation

Reduced Water Application

0

20

40

60

80

100

120

0 20 40 60 80 100 120

Clay 0.10 LFClay 0.20 LF

Cum

ulat

ive

influ

ent

(L)

Treatment

Day after initiation

26 L

Reduced Water Application

0

20

40

60

80

100

120

0 20 40 60 80 100 120

Clay 0.10 LFClay 0.20 LF

Cum

ulat

ive

influ

ent

(L)

Treatment

Day after initiation

90,000 gallons of water saved per growing acre

while maintaining growth

Reduced Water Application

0

5

10

15

20

25

0 20 40 60 80 100 120

Clay 0.1 LFClay 0.2 LF

Cum

ulat

ive

eff

luen

t (L

)

Day after initiation

Treatment

16 L

Reduced Water Application

0

5

10

15

20

25

0 20 40 60 80 100 120

Clay 0.1 LFClay 0.2 LF

Cum

ulat

ive

eff

luen

t (L

)

Day after initiation

Treatment

55,000 gallons less leachate or runoff per

growing acre

Water Buffering Capacity

Water Buffering Capacity

Real-time monitoringWeight

• Water loss• Container capacity

Water Buffering Capacity

70

75

80

85

90

95

100

00:00

06:00

12:00

18:00

00:00

06:00

12:00

18:00

00:00

06:00

12:00

18:00

00:00

06:00

12:00

18:00

00:00

06:00

12:00

18:00

00:00

06:00

12:00

18:00

00:00

Time and date

Con

tain

er

capa

city

(%

)

ClaySand

Aug 23 Aug 24 Aug 25 Aug 26 Aug 27 Aug 28

Amendment

Water Buffering Capacity

-2000

-1500

-1000

-500

0

ClaySand

5:30

7:30

9:30

11:3

0

13:3

0

15:3

0

17:3

0

19:3

0

21:3

0

Wat

er lo

ss (

ml)

daylight hours

Time (Sept.)

Amendment

Water Buffering Capacity

-2000

-1500

-1000

-500

0

ClaySand

5:30

7:30

9:30

11:3

0

13:3

0

15:3

0

17:3

0

19:3

0

21:3

0

Wat

er lo

ss (

ml)

daylight hours

Time (Sept.)

Amendment

3.4 mL m

in-1

2.7 mL m

in -1

Water Buffering Capacity

-2000

-1500

-1000

-500

0

ClaySand

5:3

0

7:3

0

9:3

0

11:

30

13:

30

15:

30

17:

30

19:

30

21:

30

Wat

er lo

ss (

ml)

daylight hours

Time (Sept.)

Amendment

334 mL

Water Buffering Capacity

-2000

-1500

-1000

-500

0

ClaySand

5:3

0

7:3

0

9:3

0

11:

30

13:3

0

15:

30

17:

30

19:3

0

21:

30

Wat

er lo

ss (

ml)

daylight hours

Time (Sept.)

Amendment

Physical Properties: 4% increase in

available water which equates into 500 ml

Water Buffering Capacity

Amendment (11% by vol.)0.25 to 0.85 mm LVMWashed, builders sand

Irrigate to minimize plant stressWater replacement to 98% CC

• 1200, 1500, 1800 HR EST

Load cell control • 94% to 98% CC

Water Buffering Capacity

BP ≤ 0.05

0

100

200

300

400

500

Load Cell PM Replacement

claysand

To

tal

dry

we

igh

t (g

)

A B A B

123 g82 g

Water Buffering Capacity

BP ≤ 0.05

0

100

200

300

400

500

Load Cell PM Replacement

claysand

Wa

ter

use

eff

eci

en

cy (

mL

g-1

)

B A B A

190 mL90 mL

Financial Support

FNRI

Columbia River Gorge, OR