Advances in Manure Management and

Areas of Research Need

Dr. Bruce T. BowmanChair, CARC Expert Committee on Manure Management

CCFIA Mid-Program Review

March 21-22, 2002

Winnipeg, MB

• 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

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 - Extension

– Refereed publications - Popular press

– Web-based information

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

• 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

Odour

Recent Research and Technology Advances

• 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

Nutrients

Recent Research and Technology Advances

• 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

Pathogens

Recent Research and Technology Advances

• 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

Greenhouse Gases

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

Knowledge Gaps

• 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

Nutrients

Knowledge Gaps

• Need to reduce pathogens levels in livestock – better understanding of shedding

• Improved manure treatment systems to kill pathogens

• Need better understanding of survivability below plow-layer in soil – practices to reduce leaching risks

• Review Research on uptake of pathogens by vegetables – implications for organic farming

Pathogens

Knowledge Gaps

• 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 & spatialC Role of carbon in nitrous oxide production

Greenhouse Gases

Knowledge Gaps

• 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

System-wide

Knowledge Gaps

• 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

System-wide

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– 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-

Efficiency• Methane captured - used for heating or

for electricity production• “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:– 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)