Optimal agricultural practices for

growing kenaf in IowaNovember 17th, 2015

Marie Bourguignon1, Ken Moore1, Sotirios Archontoulis1, Roger Hintz1, Brian Baldwin2.

1 Department of Agronomy, Iowa State University2 Plant & Soil Sciences Department, Mississippi University

What we know about kenaf…

CoreShort and

porous fibers

BastLong and valuable

fibers

FIBER

FUEL ?

What we do NOT know about kenaf…

?

What is its potential

for fuel ?

Experiment 2004 - 2005 - 2006

Treatment Unit 2004 - 2005 - 2006

Cultivar Tainung 2

Seed Density seed ha-1 185,000 278,000 370,000

Row Spacing cm 20 38 76

N Fertilizer kg ha-1 0 168

Planting Date early, late May, early June

Data Collected

MorphologicalYield, population, height & diameter,

core:bast ratio

Chemical Fiber analysis (NDF, ADF, ADL, Ash)

Yield 2004 - 2005 - 20062004

20cm 38cm 76cm 20cm 38cm 76cm 20cm 38cm 76cm

Yie

ld (

Mg

ha

-1)

0

2

4

6

8

10

12

14

16

18

185,000 s ha-1 278,000 s ha-1 370,000 s ha-1

2005

20cm 38cm 76cm 20cm 38cm 76cm 20cm 38cm 76cm

Yie

ld (

Mg

ha

-1)

0

2

4

6

8

10

12

14

16

18

185,000 s ha-1 278,000 s ha-1 370,000 s ha-1

2006

20cm 38cm 76cm 20cm 38cm 76cm 20cm 38cm 76cm

Yie

ld (

Mg

ha

-1)

0

2

4

6

8

10

12

14

16

18

185,000 s ha-1 278,000 s ha-1 370,000 s ha-1

Stem height & diameter:

Smaller stem when too crowded

Larger stem in low densities and when planted in May

Core:bast ratio:

More core when planted in May and not crowded

More bast when planted later and at 8”

Adding N reduced the ratio in 2004

Morphology 2004 - 2005

Fiber composition 2004 - 2005

BAST CORE

Cellulose 60 %• Date * row * density

• N slightly better52 %

• Higher in 2005

• N beneficial but only in

2004

Hemicellulose 16 %

• Very low in 2005

• Row * density

• N not always

beneficial

21 %

• Row * density

• N beneficial but only in

2004

Lignin 5%

• Row * density

• N not always

beneficial9 %

• Higher in 2005

• Better when planted end

of May

• N beneficial but only in

2005

Not enough information about N

No information on the growth over time

Experiment 2014 - 2015

Treatment Unit 2004 - 2005 - 2006 2014 - 2015

Cultivar Tainung 2 Tainung 2, Whitten

Seed Density seed ha-1 185,000 278,000 370,000 247,000 370,000

Row Spacing cm 20 38 76 38 76

N Fertilizer kg ha-1 0 116850 0 56 112 168 224

Planting Date Early, late May, early June Only one

Data

Collected

MorphologicalYield, population, height & diameter, core:bast ratio

Yield, population, height & diameter (biweekly)LAI (monthly), core:bast ratio

ChemicalFiber analysis (NDF, ADF, ADL, Ash)

Fiber analysis (NDF, ADF, ADL, Ash), %C, %N

Yield 2014

2014 yield was only influenced by seed density

(247,000 > 370,000)

Population varied among variety and field practices

Jun Jul Aug Sep Oct

LA

I

0

1

2

30 kg ha

-1

56 kg ha-1

112 kg ha-1

168 kg ha-1

224 kg ha-1

Jun Jul Aug Sep Oct Nov

He

igh

t (c

m)

0

50

100

150

200

250247,000 seed ha

-1

370,000 seed ha-1

Jun Jul Aug Sep Oct Nov

Dia

me

ter

(mm

)

0

5

10

15

20

25 0 kg ha-1

56 kg ha-1

112 kg ha-1

168 kg ha-1

224 kg ha-1

Growth 2014

T2 was thicker than

Whitten except for 76 cm

and 370,000 seed ha-1

Fiber quantity and quality

BAST CORE

Cellulose 55 %• Low N often beneficial

but variety dependent52 %

• Variety * management

practices

Hemicellulose 13 %

• Variety * management

practices

• High N often beneficial

20 % • Unaffected at all

Lignin 6 % • Unaffected at all 10 % • Higher in Tainung 2

Total Ash 9 %

• Higher for Whitten or in

wide rows

• High in low N

4 %• Higher for Tainung 2

• High in low N

C 42 % • Row * density * N 46 % • Unaffected at all

N 1.0 % • Higher with N 0.7 % • Higher with N

Fiber quantity: Whitten (1.6) had higher core:bast

ratio than Tainung 2 (1.5)

All factors had an effect, in variable ways

Trade-off between yield and quantity of fibers

Planting date: May seems better

Nitrogen:

No effect on yield when planted after soybean

But high effect on fiber composition

Relatively easy to grow in Iowa

Could bring diversity to agriculture and industry

Conclusions

http://mesonet.agron.iastate.edu/climodat/index.phtml?network=IACLIMATE&station=IA0200&report=17

Environmental conditions of the studies

Month

Janu

ary

Febru

ary

Mar

chApr

ilM

ay

June

July

Aug

ust

Sep

tem

ber

Octob

er

Nov

embe

r

Dec

embe

r

Month

ly M

ean T

em

pera

ture

(o

C)

-20

-10

0

10

20

Month

ly P

recip

itation (

mm

)

0

100

200

300

400

5002004

2005

2006

2007

2014

30 years long-term

Temperature

Precipitation