Transcript Advances in Manure Management and Areas of Research Need

Advances in Manure Management
and
Areas of Research Need
Dr. Bruce T. Bowman
Chair, CARC Expert Committee on Manure Management
CCFIA Mid-Program Review
March 21-22, 2002
Winnipeg, MB
Background
• Manure research has been conducted for well
over a century by our forefathers
• Technology has advanced a lot … but …
• Dealing with same major issues
– Odour
– Water quality
• Don’t seem to be fully resolving issues
Background
(cont’d)
• Challenge – no “standard manure system”
• Each manure system quite “site/farm-specific”
• Thus.. difficult to compare / assess systems
• What works for one farmer may not for another
– Best practices can be quite specific for
environmental or economic reasons
Getting the Right Information
• Tremendous increase in information on many
manure-related issues … processes, practices..
• Information is widely scattered.. Some anecdotal
• Quality of information quite diverse – same original
information may appear in multiple formats
– Grey literature
– Refereed publications
– Web-based information
- Extension
- Popular press
The Current Problem
• Liquid manure systems - more popular since
1970’s – labour-saving – relatively small
• About decade ago, livestock operations started
to get much larger – driven by global competition
• Geographic concentration of livestock operations
• Inherent weaknesses became more evident
– Increased odour
– Excess volumes of water – land application
– Excess nutrients
Recent Research and
Technology Advances
Odour
• Reducing dust levels in barns (oils)
• Bio-filters to reduce odours leaving barns
• Pit additives - most are not cost-effective
• Advances in composting technologies
- reduce odour and volume
Recent Research and
Technology Advances
Odour
• Injection techniques for liquid slurries (also disrupt
macropores)
• Negative air pressure covers for storage lagoons
• Setbacks, shelterbelts - isolate barns from public
• Pelletizing techniques for odour and water volume
reduction
Recent Research and
Technology Advances
Nutrients
• Improved (& more frequent) manure analysis
• Manure applied based on crop requirements
(NMPs); both N & P limitations being introduced in
several provinces - prevent P excesses in soil
• Animal diet efficiency - enzymes to improve
nutrient utilization —> reducing P excretion
• Precision application of liquid manure
- variable application rate; zone management of nutrients
Recent Research and
Technology Advances
Pathogens
• Advances in animal vaccination to reduce
pathogen levels
• Recent Studies on pathogen survival in soil and
water – nutrient status
• Research on pathogen transport in soil
- preferential transport
Recent Research and
Technology Advances
Greenhouse Gases
• Only recently viewed as being an important issue
• Some studies monitoring CH4 & N2O emissions from
livestock operations (manure storage/ handling)
- develop emission coefficients for various practices
• Some studies monitoring ghg emissions following
manure applications in field (liquid, solid/compost)..
Including mineral fertilizers
- C content in liquid manure affects N2O production
Knowledge Gaps
Odour
• Odour problems persist in storage, handling &
application using conventional liquid systems..
– Considerable progress with some practices…
• Injecting liquid manure (odour) continues to be a
barrier for no-till operations
• Need to develop rapid, continuous in-barn
separation and removal of solid and liquid manure
fractions (odour & ghg impacts) (confined operations)
Knowledge Gaps
Nutrients
• Need better prediction of nutrient mineralization rates
from manure sources
– Timing of release to match crop requirements
• Continue to reduce P content of livestock manures
through improved diet/feed efficiency
• Develop more precise manure application equipment
for manure nutrients (esp. solid manures)
• Implement the P index nationally as part of nutrient
management planning
Knowledge Gaps
Pathogens
• Need to reduce pathogens levels in livestock
– better understanding of shedding
• Improved manure treatment systems to kill pathogens
• Need better understanding of survivability below plowlayer in soil – practices to reduce leaching risks
• Review Research on uptake of pathogens by
vegetables – implications for organic farming
Knowledge Gaps
Greenhouse Gases
• Need to monitor and compare a range of manure
handling/ storage systems for relative ghg losses
(cost-benefit analysis)
– Compare anaerobic digestion vs composting systems vs
conventional systems .. Emission coefficients
• Require much better understanding of interactions
between factors contributing to ghg production and
losses for post-manure land application
(include roles of mineral fertilizers)
C Great source variability; quite temporal & spatial
C Role of carbon in nitrous oxide production
Knowledge Gaps
System-wide
• Need comprehensive, systematic framework
for manure management decision making
– Complex dynamic interactions between factors
– Simple change in one factor may have several
unintended impacts elsewhere in the system;
economic or environmental
– For researchers & farmers.. e.g. How to optimize
practices to reduce ghg emissions - affordable
Knowledge Gaps
System-wide
• Lack validation / verification for many manure
treatment technologies that are available in
the market place
– Which technologies work well together – on-farm
• Need research on nutrient recycling /
scavenging technologies for recovering
nutrients from liquid manures (Europe)
– Provide flexibility for nutrient utilization – optimize
nutrient balance for end use  on-site, or off-site
Back to the Problem
Conventional Liquid Manure Systems
- #1 source of problems
– Odour
• Many practices try to reduce existing odours
• Few current practices eliminate odour sources (compost)
– Water Quality
•Increased risk of water contamination after application
•Large water volumes contribute to problem
Back to the Problem
• Excess Nutrients (all manure systems)
– Nutrients Imported = Nutrients Exported
• Society (Rural Neighbours)
– Concerned with health, food safety and water quality
– Lacks confidence in current manure management
practices
New Directions
• Trend - “Treat” manure before further use for:
– On-farm land application … or
– Off-farm, value-added products
• Why?
– Reduce odours, pathogens, ghg losses
– Reduce risks of excess nutrients in water
– Restore public confidence in livestock operations
New Directions
• Closed Vessel Manure Treatment
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Conserves nutrients (better N/P balance)
Confines odour during processing/conversion
Eliminates ghg losses during processing
Liquid – AD systems
Solid – in-vessel composting (reduce N losses)
• Remove manure from source to storage as
quickly as feasible
– Reduce ghg losses.. Maximize CH4 capture
– Reduce odour production
Features of Anaerobic Digestion
Odour
• Greatly reduce odours – land application
• Ammonia emissions reduced
• Surface application of digested manure?
– Suitable for No-till operations?
Pathogens • Can be greatly reduced or eliminated
GHGs
• Minimal GHG losses during treatment
Features of Anaerobic Digestion
Nutrients
• Closed vessel, nutrients conserved
– Increased N content; better N:P ratio
– pH control to reduce application losses
– Nutrients more available for plant use
Eco• Methane captured - used for heating or
for electricity production
Efficiency
• “Green power”; distributed generation
• Energy independence, revenue source
(power generation being privatized)
Priority Research Areas
1. Develop manure management DSS
 For researchers to understand dynamic interactions
 For livestock producers to select optimum system
2. Integration of Greenhouse Gas emissions
knowledge into existing practices
 Impacts/adjustments to existing BMPs
 Balancing economic & environmental impacts
Priority Research Areas
3. Manure Treatment Technologies
 Compare AD vs Composting vs Conventional
 Verify technologies – optimum combinations
4. Post-Treatment nutrient recovery/recycling
 Flexibility to manage nutrients – on-farm/off-farm
 Balance nutrients – value-added – linked to
NMPs
Looking Ahead
Need to manage manure for:
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Nutrient value
Soil conditioning value
Energy content
Value-added products
Minimize negative environmental impacts
• Innovative partnerships for waste management
– Other Ag (food processors, rendering, deadstock)
– Municipal (residential wastes, sewage)
– Industrial (energy producers, wood chips)