impacts of biochar additions on agronomic yields kurt spokas usda-ars, soil and water management...
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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]
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: