Impacts of Biochar Additions on Agronomic Yields  

Kurt Spokas

USDA-ARS, Soil and Water Management Unit, St. Paul, MNAdjunct Professor University of Minnesota – Department of Soil, Water and Climate

Illinois Biochar Group MeetingIllinois Biochar Group MeetingISTCISTC

June 9, 2011June 9, 2011

Biochar: Soil Application

• The assumed target for biochar has been soil application

• Focus has been on “creating” Terra Preta soils

Observations of increased soil fertility and productivity. Postulated from ‘slash and burn’ historic charcoal additions

However, on the other side:

• Wood distillation plants [1800-1950’s]• Wood pyrolysis – source of chemicals and energy prior to petroleum (fossil fuel)

• Multiple large plants existed (10 cords [14 tons] per day)

• Some plants on US-EPA Superfund site list

• Other charcoal sites• Not always productive

• Reduced seed germination• Reduced plant growth

Biochar: Soil Application

(BEGLINGER AND LOCKE, 1957)

Applications date back to the beginning of modern science [1800’s]:

Soil Application… Long History

(LeFroy, 1883)

Does biochar improve agronomic yields?

Biochar Soil Application

Recent compilation of historical and recent biochar (black carbon) applications:

Biochar Soil Application

Further Observations from Existing Studies

Wood Feedstock –

Majority of observed positive yield improvements have used wood feedstock with traditional soil kiln/fire pit methods (not pyrolysis units)

Other feedstocks:

negative to no impact…

Exception: Poultry manure (higher N-content)

Significant Hurdles

1. Lack of adequate documentation of biochar properties and conditions in existing studies

2. Existing feeling that biochar = biochar

3. Once produced – Biochar is reactive

• Surface chemistry is not only a function of production and feedstock, but also of post-production conditions and storage (i.e. cooling method, activation)

• Biochars with equivalent production conditions still can be chemically and structurally different

Sorbed Organics on Oak Biochar

Slow pyrolysis

Slow pyrolysis

Fast pyrolysis

Gasifier pyrolysis

Soil kiln mound (traditional)

Equivalent production conditions

Active Biochar ResearchMN Corn Growers Association

> Examining the potential use of microwave assisted pyrolysis in the conversion of distillers grain into value added products (energy, bio-oil and biochar)

MN Dept. of Agriculture (Specialty Crop Block Grant)

> Impacts of biochar on specialty crop production

- Soil and yield impacts

- Potential bioaccumulation of other organic compounds on biochar

USDA-ARS

> Rosemount, MN Field Plots – 8 different biochars & biomass

> Laboratory assessments of GHG and VOC impacts

Conclusions Despite the long research history –

No absolute “biochar” consistent trends Highly variable material

– Production & post-production handling

Different responses to biochar Function of soil ecosystem (microbial linkage) & position on black carbon continuum

Importance of fully documenting methods of creation, handling, and properties – Allow future elucidation of factors

Several inter-related mechanisms

Biochar does act as a carbon sequestration agent As long as biochar has low oxygen to carbon (O:C) molar ratio

Looking Forward• Economics caused the shift from biomass to fossil fuels in the early

1920’s:

We at the cusp where environmental stewardship is returning the pendulum back to biomass as the source for human’s energy, chemical and agronomic needs

Research is needed to optimize both:

1. Advanced pyrolysis system development for combined energy, chemical, and biochar production

2. Subsequent utilization of biochar in a sustainable and environmentally responsible manner [not limited solely to soil application]

American Society of Agronomy

Biochar Community

AcknowledgementsI would like to acknowledge the cooperation:National Council for Air and Stream Improvement (NCASI) Universität Bonn (Germany)IRNASE-CSIC (Spain)Università di Bologna (Italy)Penn State; University of MinnesotaIllinois Sustainable Technology Center (ISTC) [Univ. of Illinois]US-EPA and other USDA-ARS locations

Dynamotive Energy SystemsNC Farm Center for Innovation and SustainabilityBest EnergiesNorthern TilthMinnesota Biomass ExchangeBiochar Brokers Chip EnergyAECOMAvello BioenergyICM, Inc.Freedom Field Energy

Partial Funding: • Minnesota Corn Growers Association/Minnesota Corn Research Production Council• Minnesota Department of Agriculture Specialty Crop Block Grant Program

Technical Support : Martin duSaire Students: Tia Phan, Lindsey Watson, Lianne Endo, Kia Yang, Eric Nooker, Ed Colosky and Amanda Bidwell

USDA-ARS Biochar and Pyrolysis Initiative

GRACEnet Project (30 locations): Greenhouse Gas Reduction and Carbon Enhancement Network

REAP Project (24 locations): Renewable Energy Assessment Project

Biochar and Pyrolysis Initiative (15 locations)

Ongoing field plot trial (6 locations)

Multi-location USDA-ARS research efforts: