NC STATE UNIVERSITY

Department of Horticultural Science

Clay Amended Pine Bark Decreases Water Use and

Phosphorus Loss

James OwenStuart Warren & Ted Bilderback

Environmental Concerns?

•Nutrients

•Water

FERTILIZER

SU

BS

TRA

TEIR

RIG

ATIO

N

The Container System

ContainerContainer

•Clay TypeStructure

•SourceLocation

•ProductionSizeTemperature

What Defines Clay Minerals?

•Clay TypeStructure

•SourceLocation

•ProductionSizeTemperature

What Defines Clay Minerals?

What Defines Clay Minerals?

•Clay TypeStructure

•SourceLocation

•ProductionParticle SizeTemperature

Materials & Methods

Design • 5 Treatments 3 Replications RCBD

24-48

4-20

TREATMENTS

8 PB : 1 Sand

8% Amendment 4-20 Dried 5-20 Calcined 24-48 Dried 24-48 Calcined

Materials & Methods• Cotoneaster dammeri ‘Skogholm’

• 14 - L Container

• 17 - 5 - 12 CRF

• Spray Stakes

Materials & Methods

DATA• Leachate Vol. Daily

NO3, NH4, P• Irrigation Vol. Weekly• Dry Weight

STATISTICS• ANOVA

Fisher’s Protected LSDTreatment Contrasts

RESULTS - Cumulative Irrigation Applied

8 Pine Bark : 1 Sand

5/20 Dried 4/20 Calcined24/48 Dried 24/48 Calcined

8 Pine Bark : 1 Sand

5/20 Dried 4/20 Calcined24/48 Dried 24/48 Calcined

40

60

80

100

120

140

160

180

48 56 64 72 80 88 96 104 112

Days after experiment initiation

Wa

ter

ap

pli

ed

(L

)

8 Pine Bark : 1 Sand y = 1.83x + 57.82, R2 = 0.99

5-20 Calcined y = 1.64x + 53.13, R2 = 0.98

24-48 Calcined y = 1.49x + 46.01, R2 = 0.98

4-20 Dried (not shown)24-48 Dried (not shown)

RESULTS - Cumulative Phosphorus Loss

y = 16.4Ln(x) - 17.2

R 2 = 0.92

y = 12.8Ln(x) - 17.3

R 2 = 0.89

y = 5.8Ln(x) - 4.9

R 2 = 0.94

0

10

20

30

40

50

60

70

3 11 19 27 35 43 51 59 67 75 83 91 99 107

Days after experiment initiation

P l

each

ed (

mg

)

8 Pine Bark : 1 Sand

5-20 Calcined (not shown)

24-48 Calcined4-20 Dried (not shown)24-48 Dried

RESULTS

• Equal growth of Cotoneaster among all treatments

• Clay Reduced Water Use – 3 to 6 gallons • container-1

– ≥ 100,000 gallons • growing acre-1

• Clay Reduced Nutrient Loss– 28% - 62% phosphorus– 50% ammonium