Biochar for Sand-Based

Root-Zone Modification

NICK CHRISTIANSSHANE BROKHOFF

IOWA STATE UNIVERSITY

BIOCHAR AND TURF

Sand-based turfgrass root-zoneUnited States Golf Association

(USGA)

BIOCHAR AND TURF turfSand-based turfgrass root-

zoneUnited States Golf Association (USGA)

4

Why biochar and turf…

Root-zone mix

Intermediate layer

Coarse gravel

Drainage tile

(USGA, 1993)

sand:peat moss 90:10 or 80:20

OBJECTIVES

Sand and biochar root-zone mix:

soil water retention properties

saturated hydraulic conductivity

rooting depth of creeping bentgrass

(Agrostis stolonifera L.)

chemical properties

• switchgrass (Panicum virgatum

• FAST PYROLYSIS• Center for Sustainable

Environmental Technologies (CSET) at Iowa State University

BIOCHAR

7

• Six volume-to-volume mixtures of biochar and sand

Treatments

Treatment Sand : Char

1 100 : 0

2 95 : 5

3 90 : 10

4 85 : 15

5 80 : 20

6 75 : 25

8

9

10

0 5 10 15 20 250.00

0.05

0.10

0.15

0.20

0.25

0.30

f(x) = 0.00716571428571428 x + 0.0916285714285717R² = 0.970126215683793

Plant Available Water of Six Biochar and Sand Mixtures (n=4)

Percentage biochar (v/v)Pla

nt

av

ail

ab

le w

ate

r (c

m3

cm

-3)

11

0 5 10 15 20 250

20

40

60

80

100

120

100

65 62

34

198

f(x) = − 3.59059188137078 x + 92.766628105266R² = 0.959532464145078

Percentage biochar (v/v)

Ks

at

(cm

hr-

1)

Ksat of Six Biochar and Sand Treatment Mixtures (n=4)

12

13

14

• Leachate

– Electroconductivity (EC)

– pH

– Total organic carbon (TOC)

– Nutrient analyses

• Soil

– Nutrient analyses

Chemical properties

15

LEACHATE pHpHpH

(-lo

g [H

+])

7.4

7.6

7.8

8.0

8.2

8.4

8.6

8.8

0 5 10 15 20 25 Biochar percentage (v/v)

16

P (

ppm

)

0

2

4

6

8

0 5 10 15 20 25 Biochar percentage (v/v)

LEACHATE P

17

Soil KK

(pp

m)

0

200

400

600

800

1000

1200

0 5 10 15 20 25 Biochar percentage (v/v)

LEACHATE K

18

• Biochar increases soil water retention

• Biochar decreases saturated hydraulic conductivity

• Biochar decreases rooting depth of creeping bentgrass in media containing more than 10% (v/v) biochar

• Biochar increases leachate EC, TOC; provides essential nutrients

Conclusions