Balancing Biomass for Balancing Biomass for Bioenergy and Conserving Bioenergy and Conserving

the Soil Resourcethe Soil Resource

Jane JohnsonJane JohnsonUSDA-ARS-USDA-ARS-

North Central Soil Conservation North Central Soil Conservation Research LaboratoryResearch Laboratory

USDA-ARS

IntroductionIntroduction

Energy paradigm is changing from Energy paradigm is changing from petroleum to mixed renewablepetroleum to mixed renewable

Sufficient energy available, but in Sufficient energy available, but in diffuse formdiffuse form

Can we be sustainable or at least Can we be sustainable or at least minimize environmental footprint?minimize environmental footprint?

Can we balance food, feed, fiber and Can we balance food, feed, fiber and fuel?fuel?

USDA-ARS

OutlineOutline

BackgroundBackground Discuss roles of non-grain biomassDiscuss roles of non-grain biomass Constraints for harvest ratesConstraints for harvest rates ExamplesExamples SummarySummary

USDA-ARS

Cellulosic biomassCellulosic biomass

NRCS plant material center

USDA-ARS

Cellulosic ethanol – sugar platform Cellulosic ethanol – sugar platform Thermochemical – controlled combustionThermochemical – controlled combustion

GasificationGasification Dimethylether (DME)Dimethylether (DME) Replace natural gasReplace natural gas

PyrolysisPyrolysisBio oil, bio char, biogasBio oil, bio char, biogas

Other bio-based products Other bio-based products

Interest in biomass for bioenergyInterest in biomass for bioenergy

USDA-ARS

Agriculture – 998 million tonsAgriculture – 998 million tons Perennial energy crops – 377 million tonsPerennial energy crops – 377 million tons ““Wastes” – 87 million tonsWastes” – 87 million tons Grain – 87 million tonsGrain – 87 million tons Crop residues – 428 million tonsCrop residues – 428 million tons

Corn stover – 256 million tonsCorn stover – 256 million tons

Forestry – 368 million tons

(projected estimates; Billion Ton Report, Perlack et al 2005)(projected estimates; Billion Ton Report, Perlack et al 2005)

Biomass for bioenergyBiomass for bioenergy

USDA-ARS

BenefitsBenefits RenewableRenewable Domestic Domestic Reduces release of Reduces release of

fossil COfossil CO22

Additional farm Additional farm commoditycommodity

RisksRisks Decreased surface Decreased surface

residuesresidues Increased erosionIncreased erosion

Off-site nutrient and Off-site nutrient and sedimentssediments

Decreased SOMDecreased SOM Decreased productivityDecreased productivity Other – loss of winter Other – loss of winter

cover, habitatcover, habitat

Biomass harvest

USDA-ARS

Primary roles of non-grain biomassPrimary roles of non-grain biomass

Protect the soil from erosion Protect the soil from erosion

USDA-ARS

Water

USDA-NRCSMorris, MN 2003

Wakeeney, KSL. Kucerik, 2004

LaPorte, IN 2004

Wind

Tillage

MN, D. Reicosky

http://www.umanitoba.ca

USDA-ARS

Primary roles of crop biomassPrimary roles of crop biomass

Protect the soil from erosion Protect the soil from erosion

Provide C and other organic inputs to Provide C and other organic inputs to support the below ground ecosystem support the below ground ecosystem

USDA-ARS

USDA-ARS

Primary roles of crop biomass Primary roles of crop biomass

Protect the soil from erosion Protect the soil from erosion Provide C and other organic inputs to support the below Provide C and other organic inputs to support the below

ground ecosystem ground ecosystem

Build and maintain soil organic matter/soil Build and maintain soil organic matter/soil organic carbonorganic carbon

USDA-ARS

Biomass management for Biomass management for Carbon (C) storageCarbon (C) storage

Storing C in soil – building humusStoring C in soil – building humus Nutrient cyclingNutrient cycling Water holding capacityWater holding capacity Improve soil aggregationImprove soil aggregation Maintain soil productivityMaintain soil productivity

Remove CORemove CO22 from atmosphere from atmosphere

USDA-ARS

Biomass management for C Biomass management for C storagestorage

C inputs > C outputs = increased SOCC inputs > C outputs = increased SOC

C InputsC Inputs Crop above Crop above

ground biomassground biomass Crop root and Crop root and

their exudatestheir exudates ManureManure

C OutputsC Outputs Respired CRespired C Erosion Erosion Tillage Tillage LeachingLeaching HarvestHarvest

USDA-ARS

So

il C

arb

on

Co

nte

nt //

Soil C Change with ManagementIntensive Ag begins

Management Changes

Stover removal

Offsetting Practices (no till, cover crops, diverse rotations, etc.)

No Offsetting Practices

Time

Credit: Wally Wilhelm, Dec. 2005

?

So

il C

arb

on

Co

nte

nt //

Soil C Change with ManagementIntensive Ag begins

Management Changes

Stover removal

Offsetting Practices (no till, cover crops, diverse rotations, etc.)

No Offsetting Practices

Time

Credit: Wally Wilhelm, Dec. 2005

?

USDA-ARS

““The need to maintain soil productivity The need to maintain soil productivity should be our first consideration and only, should be our first consideration and only, once this criterion has been met, should once this criterion has been met, should crop biomass be removed for alternative crop biomass be removed for alternative purposes.”purposes.”

William (Bill) Larson, 1979William (Bill) Larson, 1979

USDA-ARS

Minimum biomass inputs Minimum biomass inputs depends ondepends on

Precipitation and temperaturePrecipitation and temperature CropCrop Crop rotationCrop rotation TillageTillage Nutrient managementNutrient management Additional inputsAdditional inputs Limiting constraint (erosion or Limiting constraint (erosion or

carbon)carbon)

USDA-ARS

USDA-ARS Renewable Energy Assessment Project (REAP) Team Locations

USDA-ARS

REAP goals REAP goals

Determine how much biomass needs Determine how much biomass needs to stay on the land to protect soil to stay on the land to protect soil resourceresource

Compare short- and long-term Compare short- and long-term economics of using biomass economics of using biomass feedstock and soil organic inputfeedstock and soil organic input

Provide recommendations and Provide recommendations and guidelines for sustainable biomass guidelines for sustainable biomass harvestharvest

USDA-ARS

How much biomass needs to stay How much biomass needs to stay in the field?in the field?

Prevent erosionPrevent erosion Sustain belowground ecosystemSustain belowground ecosystem Build soil organic matterBuild soil organic matter Sequester CSequester C Maintain productivityMaintain productivity

USDA-ARS

ConstraintsConstraints

ErosionErosion Reduces Reduces

productivityproductivity Degrades soilDegrades soil Degrades water Degrades water

qualityquality Amount as % Amount as %

surface coversurface cover

Soil organic matterSoil organic matter Reduces Reduces

productivityproductivity Reduces water Reduces water

holding capacityholding capacity Degrades soilDegrades soil Contributed to Contributed to

increased atm increased atm COCO22

Total inputsTotal inputs

USDA-ARS

Harvestable Stover based on erosion constraints and (1995-2000) corn management practices Region Avg. corn

yld Percentage Removed

Stover Collected

Stover Left

Bu acre-1 % Tons acre-1 IA-MN 143 67.7 2.30 1.1 IL-IN 139 60.6 1.99 1.3 NE-Platte River

143 41.4 1.39 2.0

Based on Graham et al. 2007 AJ 99:1-11

USDA-ARS

Minimum inputs estimated by a simple linear relationship

bxay

• y is change in soil organic carbon change • x is the amount of C (or biomass) input annually

Larson et al., 1972; Paustian et al., 1997; Follett et al., 2005; Johnson et al., 2006

USDA-ARS

Critical biomass inputsLarson et al., 1972

y = 5.55x - 13.25R2 = 0.975

-15

-10

-5

0

5

10

15

20

25

30

0 2 4 6 8

Aboveground inputston/acre

% c

ha

ng

e i

n C

USDA-ARS

Estimated minimum biomass inputs to prevent loss of SOC Crop Rotation Tillage Minimum

biomass Cover

Ton acre-1 % Corn continuous MBP 3.39 5 Corn-soybean MBP 5.58 5 Corn continuous Chisel/NT 2.36 30-85 Corn-soybean Chisel/NT 3.52 30-85 Johnson et al (2006) JSWC 61(4) 121A-125A; Johnson et al (2006) AJ 98:622-636

USDA-ARS

Maximum county average 2006 yield Corn

yield Biomass

yield Min.

biomass In

field Harvested

States Bu a-1 Ton a-1 % % IA 193.0 4.07 2.36 57.9 42.1 MN 181.0 3.82 2.36 61.8 38.2 IN 178.6 3.77 2.36 62.6 37.4 IL 181.0 3.82 2.36 61.8 38.2 USDA-NASS; Johnson et al (2006) JSWC 61(4) 121A-125A; Johnson et al (2006) AJ 98:622-636

Example, assumes conservation tillage and continuous corn

USDA-ARS

Sto

ver

to r

eta

in (

Mg

ha-1)

0

5

10

15

20

Sto

ver

to r

eta

in (

ton

ac

re-1)

0

2

4

6

8Soil Organic CarbonWater ErosionWind Erosion

Continuous corn Corn-soybean

Moldboardplow

No orconserv.

tillage

Moldboardplow

No orconserv.

tillage

7.58

3.11

1.73

5.25

12.50

7.90

0.65

7.98

0.960.14

2.74

0.15

Wilhelm et al., 2007, AJ

USDA-ARSGrain yield (Mg ha-1)

5 10 15 20 25

Har

vest

able

sto

ver

(Mg

ha-1

)

-5

0

5

10

15

20

Grain yield (bu acre-1)

100 150 200 250 300 350 400

Har

vest

able

sto

ver

(to

n a

cre-1

)

-2

0

2

4

6

8C-C, No or conserv. tillageC-C, Moldboard plowC-S, No or conserv. tillageC-S, Moldboard plow

Wilhelm et al, 2007 AJ

USDA-ARS

Products:Products: Guidelines for crop and soil management Guidelines for crop and soil management

to ensure sustainable harvestto ensure sustainable harvest Predictive tools for crop biomass harvestPredictive tools for crop biomass harvest Tools to assess short and long-term Tools to assess short and long-term

trade-offs (environmental and economic)trade-offs (environmental and economic)

Outcome: Outcome: Biomass energy industry based on Biomass energy industry based on

sustainable management practices.sustainable management practices.

USDA-ARS

Current projectsCurrent projects

Biomass removal studyBiomass removal study Tillage: Tillage:

No Till (Established 1995)No Till (Established 1995) No Till (Established 2005)No Till (Established 2005) Chisel Plow, spring diskChisel Plow, spring disk

Removal rates: 0, 50, 75 Removal rates: 0, 50, 75 and 100% of rowsand 100% of rows

Monitor: biomass produced, Monitor: biomass produced, returned, soil carbon (0-returned, soil carbon (0-100 cm), yield100 cm), yield

USDA-ARS

Carbon Crop StudyCarbon Crop StudyEstablished 2000, modified 2007Established 2000, modified 2007

No tillageNo tillage

TRT Rotation 1 Switchgrass - spring harvest 2 Switchgrass - autumn harvest 3 Corn + winter rye/Forage Soybeans + Winter Lentils/Wheat + Hairy Vetch 4 Wheat + Hairy Vetch/Corn + winter rye/ Forage Soybeans + Winter Lentils 5 Corn/Soybean/Wheat + Alfalfa/Alfalfa/Alfalfa 6 Soybean/Corn 7 Big Bluestem spring harvest 8 Big Bluestem autumn harvest 9 Forage Soybeans + Winter Lentils/Wheat + Hairy Vetch /Corn + winter rye

10 Big Bluestem + clover (autumn harvest) 11 Alfalfa/Corn/Soybean/Wheat + Alfalfa/Alfalfa/Alfalfa 12 Switchgrass + clover (autumn harvest)

USDA-ARS

Related issuesRelated issues

No perfect solutionNo perfect solution Fossil fuel – finite, huge environmental Fossil fuel – finite, huge environmental

footprintfootprint Water to grow cropWater to grow crop Water for conversion – energy Water for conversion – energy

platform dependentplatform dependent Off-site impacts of nutrients/pesticidesOff-site impacts of nutrients/pesticides Habitat Habitat

USDA-ARS

Its about the future: finding balance