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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
Recommended