TATION

AARHUS UNIVERSITY

Farm scale modelling of greenhouse gas emissions and mitigation

Professor Jørgen E. Olesen

1

AARHUS UNIVERSITY

Activities

› DK projects: farm scale modelling of mitigation potentials for organic

farmers, farm scale modelling of mitigation in intensive livestock and crop

farms

› AnimalChange: farm scale modelling in Europe and developing countries

of emissions, mitigation and adaptation

› South China (Kaiping): Carbon and nitrogen cycling in different traditional

farming systems to estimate enviromental (and GHG) load

› Vietnam (completed): Emissions of greenhouse gases from various types

of smallholder farmers (different ethnic groups)

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Carbon and nitrogen flows on farms

Feed

Livestock

Soil/crops

Manure

Import

(CO2, N2O)

Export in meat/milk

Treatment

(bioenergy, composting)

Emissions

(CH4, NH3, NO3, N2O)

Emissions

(CO2, NH3, NO3, N2O)

Fertiliser

(CO2, N2O)

Emissions

(CH4)

Agroecology

Feeding strategy and

additives

Manure

treatment

Landscape

design

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The FarmGHG model (originally designed for European dairy farms)

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Data needed for modelling farm GHGs

› Imports of goods (and energy) to the farm (and to the household)

› Farm land allocations (permanent crops, arable crops, ponds, non-

utilised area)

› Farm livestock (stocks and flows of animals)

› Crop management (crop type, timing of sowing/harvesting, fertilisation,

crop protection)

› Livestock management (feeding, breeding, milking, slaughtering, timing)

› Crop and livestock production (yield) – if not modelled by the model

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Challenges of complex systems

Wide range of environmental

conditions giving a widely

different biogeochemical reactions

Defining system boundaries

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Challenges of complex systems

Wide range of crops and

livestock

Many inter-linkages on farm

in time and space

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Challenges of complex systems

Changing systems

structures and

boundaries

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Need for simplification

› Properly define farm (system) boundaries (e.g. by land, structures,

buildings)

› Define main structures on the farm (crops, livestock, manure storages,

ponds) and their interlinkages

› Get good data for imports and exports to/from the farm

› Focus on the main crops and animals on the farm and get data on their

extent and management

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Estimating emissions

› Modelling flows of carbon and nitrogen › Nitrogen inputs in fertilisers, manure and biological fixation

› Plant productivity

› Animal efficiency

› Animal waste management

› Modelling emissions of methane and nitrous oxide › IPCC emission factor approach

› Biogeochemical models

› Modelling (changes in) carbon stocks › Vegetation models

› Soil models (simple or complex)

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Data sources

› Remote sensing › Land allocation

› Vegetation duration and development

› Farm surveys › Trade in and out of the farm

› Crop area and management

› Livestock numbers and management

› Manure managment

› Monitoring › Production at regional scale

› C and N flows at the landscape (rivers, non-agricultural land)

› Literature and controlled experiments

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Challenges and gaps

› Define farm system boundary (allow for changing boundaries)

› Develop flexible and modular tool for linking farm C and N flows

› Design simple protocol for quantifying stocks and flows of C and N

between main farm components and the outside (standard, actual)

› Incorporate emission modelling (flexible tier) with C+N flows – sensitive

to enviroment and management

› Allow for assessment of mitigation (and adaptation) options

› Issues: › Accounting and verification of activity data in complex systems

› Uncertainty assessments

› We do not scientifically understand many of these complex systems