soil and crop yield response to harvesting crop …plant cell envir. 29:315-330. reap residue...
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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