Soil and Crop Yield Response to Harvesting Crop Residues for Biofuel

REAP - Renewable Energy Assessment Project

Wally Wilhelm, Lead ScientistUSDA-ARSLincoln, NE

The problem

Renewable motor fuel30 x ’3030% motor fuel from renewable sources by 2030

Field after field of corn residue“Going to waste”Potential source of biomass for energy

Can crop residues be removed from the land sustainably?

REAP

REAP Objectives

Residue needed to maintain soil function and sustain productionTrade-off for residue use as bioenergy versus soil carbon feedstockAlgorithm to guide sustainable harvest of residue for biomass ethanolManagement strategies for sustainable harvest of residue

REAP

REAP (NP 202 - Soil Resource Management)

Cross Location Research (CLR) projectCommon objectives for efforts at several locationsRegional/National effort

FundingExisting local projects

StaffVolunteerCommitmentEnthusiasm

REAP

EtOH

Hero GollanyPendleton, OR

Diane Stott,W. Lafayette, IN

Wally WilhelmGary VarvelLincoln, NE

Shannon OsborneBrookings, SD

Jane JohnsonDon Reicosky

Morris, MN

Ron FollettFt. Collins, CO

John BakerEd Clapp

Tyson OchsnerSt. Paul, MN

Doug KarlenCindy Cambardella

Ames, IA

Francisco ArriagaAuburn, AL

REAP Team

REAP

Hero GollanyPendleton, OR

Diane Stott,W. Lafayette, IN

Wally WilhelmGary VarvelLincoln, NE

Shannon OsborneBrookings, SD

Jane JohnsonDon Reicosky

Morris, MN

Ron FollettFt. Collins, CO

John BakerEd Clapp

Tyson OchsnerSt. Paul, MN

Doug KarlenCindy Cambardella

Ames, IA

Francisco Arriaga

Auburn, AL

REAP Team

REAP

CQESTRSimulation of

SOC Dynamics

Long-term Studies on SOC

NRCS Linkage

SMAF

Anticipated products

Management practicesSustainable harvest of residue

AlgorithmGuide sustainable residue harvest

Decision support tool and guidelinesHow much residue must be retained?Trade-off between bio-product and retention for soil carbon

REAP

Customers

Crop producersUS Department of EnergyBiomass ethanol producersAction agencies(e.g., NRCS, EPA)

REAP

DOE-ARS Cooperation

DOE

Industry

ARS EtOHEtOH

StoverStover

SustainabilitySustainabilityREAP

Residue needed to maintain SOC

136.3±1.0mbpAll

55.5±1.1mbpWheat

54.5±0.4Chisel/ntAll

67.5±1.0mbpCorn

nMg ha-1Tillage*Crop rotation

Johnson et al. 2006. Agron. J. 98:622-636.

-10

-5

0

5

10

15

20

0 5 10 15 20 25

Grian yield (Mg ha-1)

Har

vest

able

sto

ver (

Mg

ha-1

)

Stover producedCT-CCMBP-CCCT-CSMBP-CS

* mbp = moldboard plownt = no tillage

REAP

Residue needed to maintain SOC

136.3±1.0mbpAll

55.5±1.1mbpWheat

54.5±0.4Chisel/ntAll

67.5±1.0mbpCorn

nMg ha-1Tillage*Crop rotation

Johnson et al. 2006. Agron. J. 98:622-636.

-10

-5

0

5

10

15

20

0 5 10 15 20 25

Grain yield (Mg ha-1)

Har

vest

able

sto

ver (

Mg

ha-1

)

Stover producedCT-CCMBP-CCCT-CSMBP-CS

* mbp = moldboard plownt = no tillage

REAP

240 bu ac-1

95 bu ac-1

Soil C changeSo

il ca

rbon

Time

Managementchange

CultivationStover harvest

REAP

Soil C changeSo

il ca

rbon

Time

Managementchange

CultivationStover harvest and ?

REAP

Soil C changeSo

il ca

rbon

Time

Managementchange

CultivationStover harvest and

change rotationcover cropreduced tillageincrease yield

REAP

Change allocation of biomass

Soil carbon

Food

FeedFiber

Fuel

REAP

Change allocation of biomass

Soil carbon

Food

Feed

Fiber

Fuel

Soil carbon

Food

FeedFiber

Fuel

REAP

Change allocation of biomass vs. increase total biomass production

Soil carbon

Food

Feed

Fiber

Fuel

Increase photosynthetic efficiency 25%, from 4% 5%

Fuel

Fiber

Feed

Food

Soil carbon

Long et al. 2006. Plant Cell Envir. 29:315-330. REAP

Residue Management Study

0.800.020.130.172.91Grain

0.86

r2

SlopeIntercept

0.040.290.314.34Residue

SEb1**SEb0

*

Y Variable

Coefficient

02468

10

0 4 8 12

Applied residue (Mg/ha)Yi

eld

(Mg/

ha)

Grain

Residue

Over all years

* Mg/ha** Mg/ha / Mg/ha residue applied

(Wilhelm et al., 1986)

REAP

Residue Management StudySoil organic matter (0-30 cm)

20

22

24

26

28

30

0 50 100 150

Amount of previous crop residue returned (%)

Soil

orga

nic

mat

ter

(g k

g-1

)

After 6 yr of treatment application (cont. corn, no tillage)

(Maskina et al., 1993)

REAP

Grain yield

2001

0

4

8

12

0 50 100

Residue removed (%)

Gra

in y

ield

(Mg

ha-1

)

DiskNo tillage

2002

0

4

8

12

0 50 100

Residue removed (%)

Gra

in y

ield

(Mg

ha-1

)

DiskNo tillage

REAP

Multiple biomassMany technologiesConservationReduced expectationsAsking, and answering, the right question