soil nutrient balances - uk tapas action presentation by david fernall agri-environment statistics
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Soil Nutrient Balances - UK TAPAS Action Presentation by David Fernall Agri-environment Statistics Defra Coordination meeting for TAPAS actions "CALCULATING REGIONAL GROSS NUTRIENT BALANCES” Luxembourg Wednesday 25 th June, 2008. Soil Nutrient Balances - UK TAPAS Action Overview - PowerPoint PPT PresentationTRANSCRIPT
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionPresentation by David FernallAgri-environment StatisticsDefra
Coordination meeting for TAPAS actions "CALCULATING REGIONAL GROSS NUTRIENT BALANCES”
LuxembourgWednesday 25th June, 2008
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionOverview Review of:
• policy needs• overall approach• current methodology• data sources
physical data coefficients
Development of: • system (IT) for calculating balances• outputs and presentation methods
Project approach and summary of findings so far
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS Action Review of policy needs Strong interest from nutrient management, air quality and
water quality policy areas in Defra But may be no “one size fits all” solution for all purposes Environmentally relevant geographic units
• e.g. river catchments, NVZs, Joint Character Areas Agriculturally relevant units
• e.g. by farm sector Consider hybrid approach using
• Full data sets for benchmark years• Approximations for intervening years
Methodology must be “policy sensitive/responsive”• change in livestock breeds, feed regimes, housing regime
GIS (maps) ideal format for presenting results
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS Action Review of overall approach Overall, GNB useful indicator of overall risk of
environmental damage But approach has both strengths & weaknesses Strengths
• Robust generic tool• Relatively simple and transparent• Consistent approach allows benchmarking between MS• Allows analysis of trends over time• Good time series data already available (in UK)
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS Action Review of overall approach Weaknesses
• Large volume of data to collate and calculate• Coefficients hard to maintain• Complexity & range of components result in scope for
wide variation in estimatesADAS study gave estimates 50% higher
• Needs clear co-ordination and single provider• Policy areas have sponsored more elaborate &
focussed tools (models, databases)• No attempt to estimate loss pathways• No interpretation of cumulative effects of
balance/surplus
Joint Workshop, Luxembourg, June 08
1.1 FertilisersPhysicalNitrogen fertilisersSewage sludgeTonnes
Sheet nameData type
Data items
Units
Flowchart of OECD nutrient balance methodology
1.2 LivestockPhysicalLivestock
No. head
1.3 WithdrawalsPhysicalManure withdrawalsChange in manure stocksTonnes
Sheet nameData type
Data items
Units
Sheet nameData type
Data items
Units
1.4 Crops & foragePhysicalCrop productionPasture productionTonnes
Sheet nameData type
Data items
Units
1.5 Seeds & plantingPhysicalSeed quantities
Tonnes
Sheet nameData type
Data items
Units
1.6 BiologicalPhysicalLeguminous cropsOrganisms in arable/grassHa
Sheet nameData type
Data items
Units
1.7 Land UsePhysicalCropsPastureHa
Sheet nameData type
Data items
Units
2.1 FertilisersCoefficientNitrogen fertilisersSewage sludgekg(N)/Tonne
Sheet nameData type
Data items
Units
2.2 ManureCoefficientLivestock
kg/head/year
2.3 WithdrawalsCoefficientManure withdrawalsChange in manure stockskg(N)/Tonne
Sheet nameData type
Data items
Units
Sheet nameData type
Data items
Units
2.4 Crops & forageCoefficientCrop productionPasture productionkg(N)/Tonne
Sheet nameData type
Data items
Units
Sheet nameData type
Data items
Units
2.6 BiologicalCoefficientLeguminous cropsOrganisms in arable/grassKg(N)/Ha
Sheet nameData type
Data items
Units
2.7 DepositionCoefficientCropsPastureKg(N)/Ha
Sheet nameData type
Data items
Units
3.1.1 FertilisersVolumeNitrogen fertilisersSewage sludgeTonnes N/P
Sheet nameData type
Data items
Units
3.1.2 ManureVolumeLivestock
Tonnes N/P
3.1.3 WithdrawalsVolumeManure withdrawalsChange in manure stocksTonnes N/P
Sheet nameData type
Data items
Units
Sheet nameData type
Data items
Units
3.1.4 Crops & forageVolumeCrop productionPasture productionTonnes N/P
Sheet nameData type
Data items
Units
3.1.5 Seeds & plantingVolumeSeed quantities
Tonnes N/P
Sheet nameData type
Data items
Units
3.1.6 BiologicalVolumeLeguminous cropsOrganisms in arable/grassTonnes N/P
Sheet nameData type
Data items
Units
3.1.7 DepositionVolumeCropsPastureTonnes N/P
Sheet nameData type
Data items
Units
4.1.1 BalanceBalanceTotal inputsTotal outputsTonnes N/P
Sheet nameData type
Data items
Units
- -
++ +
=
2.5 Seeds & plantingCoefficientSeed quantities
Kg(N)/Tonne
Physical data
Coefficients
Volumes(tonnes/N)
Balance(tonnes/N)
+
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionReview of overall approach Gross balance or farm balance Gross or net balance (i.e. net of all air emissions) OECD Balance not net of gaseous emissions during housing
• Need to account for this to get a true “soil” balance• But then include atmospheric deposition from this source
Different results/interpretation when loadings presented as:• per ha of land• per ha agriculturally managed land• per ha fertilised land
IPCC tier 1 & 2 methodologies for nitrous oxide emissions from agricultural soils have some similar elements – we will review and compare in this project
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionReview of overall approach – estimates oftotal loading and loss pathways Balance gives overall measure of environmental pressure but:
• No account of farm practices affecting likely impact• No estimate of fate of nutrients/loss pathways
Possible variables/factors to account for:• Manure/slurry storage (e.g. crusting)• Timing & method of manure spreading (e.g. direct injection)• Livestock housing (e.g. concrete floors)• Climatic conditions – rainfall, temperature• Crop sowing time/ground cover• Soil conditions - slope, soil type, organic matter
Identify methods to estimate loss pathways• E.g. NARSES model to estimate ammonia emissions
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionReview of methodology - Specific issues for small area
balances How much spatial variation is there?
• Only calculate balances at spatial scale justified by variation Need to optimise trade-off between spatial precision and data
reliability Simplification required where data do not support full
calculations at fine spatial scale (NUTS3):-• e.g. Calculate at aggregated level (NUTS1) and disaggregate
to NUTS3 by manure output & crop uptake data
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionReview of methodology – a simplified regional approach ADAS developed simplified approach at NUTS 1 level for UK
• Net balance per unit (ha, animal) derived to apply to crop areas and livestock numbers
Useful for quick predictions based on modelled forecasts of changes in farming
Project will assess reliability of this approach, consider other possibilities, and make recommendations
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionReview of data sources Sensitivity analysis to determine relative contribution of data
components Inform priority for improving quality of data items Key issues:
• Availability• Spatial scale• Reliability• Timeliness• Future proof
Joint Workshop, Luxembourg, June 08
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionReview of data sources - physical data Livestock numbers from FSS based on snapshot estimates for June
each year Population profile available for cattle from Cattle Tracing Scheme
• Profile data will give slightly improved estimates where cycles are annual and pattern is regular
• Becomes more important in event of external shocks (e.g. disease outbreak)
Clear need for improved estimates of fodder production Fodder requirements – may be scope to estimate based on livestock
(meat/milk) production and animal feed volumes• (a) Meat/milk production (b) fodder + (c) feed
Fertiliser use highly correlated with crop type• Reliable estimates at fine spatial scale are possible
Manure use – little movement of manure between farms• Therefore assumptions valid at NUTS3 but not at farm level or 1 km2
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionReview of data sources - physical data
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionReview of data sources - coefficients Difficult to assess quality of coefficients Need to match to available physical data e.g. livestock
categories from FSS Variation by region and over time – real issue is to ensure
coefficients are adjusted to account for all relevant variables• e.g. milk yield, feed regime, pasture quality
Consider scope to scale coefficients by relevant “controlling” factor rather than update regularly
• e.g. adjust for milk yield Need to harmonise/ensure consistency across all countries
and, indeed, within (?case for UK “National Statistic”?) Strongly support coefficients library with metadata
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionDevelopment of IT system for calculating balances OECD spreadsheet system modified to produce NUTS1 level
balances Access-based system being developed to produce NUTS3
level balances Automatic links to data sources where possible Aim to develop a simple, transparent, maintainable system Flexible design to produce balances at different geographic
levels Generic structure to allow use by any country
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionDevelopment of outputs and presentation methods Gross balances – but components also very policy relevant Optional modules for:
• gaseous emissions during housing/storage• emissions per ha of land, grazed land or managed land
Maps at NUTS 3 for England• Total loadings per ha• Variation from mean loading or critical loading• Change over time
Simplified method developed to produce early estimates at NUTS1 and 3
Joint Workshop, Luxembourg, June 08
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionProject approach Use of in-house expertise
• Policy (Nutrient management, Air quality, Water Quality, Climate Change)
• Science & Applied Statistics (Alistair Murray)• Analysts (Dave Fernall, Matt Elliott, Alison Wray)
External expertise• ADAS (Martyn Silgram, Paul Newell-Price, Ken Smith)• IGER – Institute of Grassland and Environmental
Research
Joint Workshop, Luxembourg, June 08
Soil Nutrient Balances - UK TAPAS ActionSummaryWide range of issues identified on policy needs, methodology, data
and presentation UK figures submitted for OECD balances need reviewing Gross balance approach generally sound but has scope for adapting
to meet specific policy needs Methodology must be “policy sensitive” and track outcomes Full system for results at fine spatial resolution for baseline years Consider developing simplified approach to use in intervening years Scope to improve data sources for physical data Scope to use scaling factor to adjust coefficients over time/space Use geographic units relevant to policy needs Use of GIS to produce NUTS3 level maps showing state and trend Building in-house capability and expertise in this area