Some Learning from the Demonstration

Test Catchments Programme (DTC)

Bob Harris

With thanks to Adie Collins, Kevin Hiscock, Andrew Lovett, Alex Inmanand many others 1

Key Features• Multiple research institutes

working on 3 separate catchments, but co-ordinated

• Funded centrally but with additional funding derived locally to add value

• Long term (from 2010 now 8+ years) – a platform for research rather than a project

• High frequency monitoring to understand processes

• Social science aspects became as important as natural science

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The DTC Catchments

Wensum(Norfolk)

Arable farming

University of East Anglia, Cranfield University, British Geological Survey, Entec,

NIAB and others...

Eden(Cumbria)

Livestock and mixed upland farming

Lancaster University, Newcastle University,

Durham University, University of Cumbria, Eden

Rivers Trust, CEH and others...

Tamar(Devon/Cornwall)

Dairy, beef and sheep farming

Avon(Hampshire)

Mixed lowland farming

ADAS, University of Reading, University of Bristol, QMUL, ENTEC, University of Exeter and others...

Phase 1 2010 – 2014

Phase 22014 – 2018

Phase 32018 – 2019

The DTC programmeaims to evaluate the extent to which on-farm mitigation measures can cost-effectively reduce the impacts of water pollution on river ecology while maintaining food production capacity.

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– an interesting evolution

• Set up to look at improving water quality – make up of research consortia initially scientific, with an analytic/reductionist approach.

• Subsequently realised that social science aspects were important – but difficult to integrate

• And then the economic issues became dominant in terms of policy-making

• So the research questions changed/evolved… before the answers to the original questions had been answered

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Catchment science – the challenge of detecting change

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What has Defra got out of DTC?• Understanding catchment systems

– Causes, effects and trends in multiple pollutants– Timeframe within which we can achieve water quality goals

• Designing interventions– Cost effectiveness of combinations of measures– Targeting of measures

• Ways to influence land managers– Understand behaviours– Stakeholder led approaches

• Monitoring/ research methods– Developing new approaches

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Some key findings

Diffuse Pollution – understanding the processes

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Initial rainfall dilution

Subsequent soil leaching

Rainfall Response: Nitrate

Prolonged elevated concentrations

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Rainfall Response: Phosphorus & Sediment

Surface runoff initiated

Rapid return to pre-event conditions

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Interrogating the evidenceImportant to monitor all nutrient fractions, to fully understand the

sources/pressures impacting on ecosystems and provide sensitivity for detecting post-measure changes

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11.5

22.5

33.5

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Priors Farm Cool's Cottage Ebble (upstream) Ebble (downstream) Kingston Deverill Brixton Deverill Burracott Bridge Caudworthy Ford

Annu

al lo

ad (k

g P

ha-1

)

Particulate phosphorusDissolved organic phosphorusSoluble reactive phosphorus

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1015202530354045

Priors Farm Cool's Cottage Ebble (upstream) Ebble (downstream) Kingston Deverill Brixton Deverill Burracott Bridge Caudworthy Ford

Annu

al lo

ad (k

g N

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) Particulate organic nitrogenDissolved organic nitrogenTotal oxidised nitrogen20

1220

1320

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2012

2013

2016

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Diffuse Pollution Hydrochemistry 1• Catchment characteristics control nature/timing of nutrient flux to waters

• Nutrient and sediment delivery is episodic – can only be fully understood through high frequency monitoring (minimum daily), but the uncertainties in observational data, even at high frequency, are high.

• Nutrient chemistry varies according to landscape character – and can be underestimated if monitoring relies on inorganic nutrient fractions alone

• Clay catchments have quickflow responses dominated by overland flow:– N and P delivery dominated by particulate and organic matter fluxes from surface deposits– Sediment delivery significantly affects ecosystem responses to diffuse agricultural pollution

• Permeable (Chalk) catchments have slower responses dominated by baseflow from aquifers

– Nitrogen flux dominated by nitrate leaching from soils to groundwater– Phosphorus delivery is dominated by erosion of P-rich soils from arable land– P-rich fine sediments stored in gravel bed rivers contribute significant ecosystem impacts

• Interannual variation in nutrient loading is marked, limiting our ability to detect change in response to mitigation measures.

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• Soluble reactive P delivery is a minor component of P available to biota and contributing to ecosystem impacts in rural catchments

• N delivery is not dominated by nitrate-N, except in groundwater-dominated catchments and is never the sole contributor to ecosystem impacts

• Organic and particulate N and P generate substantial impacts on stream ecosystem health in catchments, particularly in relation to livestock farming

• Instream nutrient processing generates consequences downstream

• Successful mitigation requires multiple stressor control, including management of nutrient pools accumulated in agricultural soils, aquifers, wetlands, stream sediments and the biota

• Mitigation response times are likely to be controlled by:– The scale of the enrichment problem relative to baseline conditions– The size of the nutrient pools accumulated within the system– The residence (flushing) time of the catchment, and– The scale and targeting of the mitigation effort

Diffuse Pollution Hydrochemistry 2

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Some key findings –

Social science – understanding farmer behaviours

At the catchment scale, people and their livelihoods are a significant part of the system… a flow of ideas and a shared dialogue of learning

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Beliefs.....a conviction an individual or group accepts as true,

regardless of the lack of verifiable evidence.

• Farmers more likely to adopt a measure if they believe it will deliver tangible environmental benefits

• Providing information and motivating farmers to process it are important in changing beliefs

• Motivation to process information is low because farmers not convinced there is a case for action. Realisation of the problem is a first vital step

• Farmers recognise links between farming practice and water pollution but confused over scale and severity, compared to other sector inputs – so unsure whether they can make a difference

• Farmers have seldom been presented with chemical/ecological data at the local level to help their understanding

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Agency…the capacity of individuals to act independently and make their own

free choices.

• Many farmers lack basic knowledge - e.g. assessment of soil health• Lack of control over events caused by changing weather patterns:

‘When you get seven inches of rain falling in a few hours, which seems to happen more often nowadays, there’s no soil that can handle that no matter how well it is managed. You can do what you want but you can’t control the weather’

• Lack of security of tenure (and a reluctance to engage in longer-term activity that may not benefit them)

• Time poverty is a barrier (e.g. undertaking non-productive work incl. training)

• Debt levels preventing investment in much needed farm infrastructure - e.g. manure storage, yards, tracks

• Lack of long-term financial security and feeling of financial disempowerment ( perceive themselves as price takers not price makers, uncertainty over Brexit)

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• Strong sense among farmers that earning a living from the environment is a less noble occupation than being a producer of food.

• So, the norm within farming communities is productivist. Acting in contradiction to this ideology carries reputational risks and moves to challenge productivity goals likely to be met with resistance

‘If I were to get the same money as my neighbour but I’m getting it from the environment whilst he is producing food, I’d feel a fraud. I suppose it’s a

macho thing us farmers have got in us’

‘This farm used to be known to everyone as a real gem, a really productive bit of land. Then it got taken over by someone from outside – not a farmer – and completely given over to the environment. I think you could describe this as a

complete waste’

Social norms...rules that govern how individuals within a group should behave

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Social norms (contd.)

• Family, neighbours, farming groups more likely to exert influence than the conservation community

• Farmers don’t seek recognition from their peers for undertaking pollution mitigation and public pressure to deliver mitigation activity perceived as low

• Supply chain pressure to deliver mitigation activity also perceived as low, but growing due to lobbying activity of environmental NGOs

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Networks and relationships• The uptake of measures more likely if an environmental practice is

demonstrated by someone within a farmer’s social network• Well interconnected individuals likely to have a cohesiveness

which enables new ideas to be processed and accepted• But… acceptance of new ideas may prove limited where social

norms favouring status quo are strong• Farmers see value in localised networks populated by farmers with

similar farming systems• Farmers prefer to learn from other farmers due to perceived

applied experience and lack of external agenda (they fear being ‘outnumbered by others’)

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Some key findings

Measures – what works where, why and how much

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Defra/ADAS User Guide 85 agricultural

measures

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Collecting & using roof water in the farm yard

A farm with annual rainfall of 1.2m/yr on a roof of 20m x 30m:

Cost: Guttering > £20

Saving: 1) 20m x 30m = 600m2 produces 720m3 water in slurry pit (pumping£0.50/m3) = £360/yr

2) 720m3 water (mains £1.57/m3) = £1130/yr

Further savings are realised if you consider, reduced soil compaction & pollution risk reduction

Thanks to Westcountry Rivers Trust

Riverbank fencingCost: Fencing = £250

Savings: Fencing preventing lameness, straying and infection saving £2 per animal per year. Also reducing fluke infection. On a 200 head dairy unit the fencing more than paid for itself in the first year = £400/yr

Thanks to Westcountry Rivers Trust

First Cover Crop Trial

Block PCover crop

Block LCover cropBlock J

Fallow

2013/14 Trial 143 ha Nine fields in three blocks (J, L and P)

with different tillage methods Winter barley/wheat > spring beans Oilseed Radish cover crop on two blocks Sown August 2013, in mid-January 2014

sprayed with glyphosate Regular sampling of field drains over

winter to assess nitrate leaching

Potash

Far Hempsky

First Hempsky

Middle Hempsky

Sheds Field

Swanhills

Gatehouse

Dunkirk

Moor Hall Field

Second Trial Site

Nutrients: Winter Cover Crops

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Trial 1: November 2013Winter Cover Crops

Block J Block P

Block L

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Field Drain MonitoringWinter Cover Crops

P = 75% reduction in N losses relative to fallowL = 88% reduction in N losses relative to fallow

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Economics: Farm returnsWinter Cover Crops

Acknowledgement: Data supplied by Salle Farms Co.

Output 8-12%

higher with cover crop

Costs £120–160/ha

higher with cover crop

Block J Block P Block LFallow Cover crop Cover crop

Gross output beans: Yield (t/ha)Output at £260/t (£/ha)

5.801334

6.551435

6.241506

Costs: Establishment (£/ha)

Applications (£/ha)

Variable costs (£/ha)

Harvesting (£/ha)

Total costs (£/ha)

96

90

318

85

589

128

120

415

85

704

67

120

432

85

748Margin (£/ha) 745 731 758

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Sediment: Silt traps

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InstallationRoadside Silt Traps

£15,000 Funded by Norfolk Rivers Trust &

Broadland Catchment Partnership

Constructed October 2016

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Sediment retention

Silt Trap 3 (Nov 2016 – Nov 2017)

Sediment retained: 7,253 kgDamage cost: £392Phosphorus retained: 11.6 kgDamage cost: £148Nitrogen retained: 29.7 kgDamage cost: £13Total mitigated damage cost: £553Trap cost: £3,400Annual maintenance: £150

River sediment load downstream

2011-2016 average: 15 t y-1

2016/17: 6.3 t y-1

Damage costs per tonne

Total Phosphorus: £12,790Total Nitrogen: £430Sediment: £54

Roadside Silt Traps

Payback time: ~8.5 years

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• Simple measures can be effective for sediment trapping (e.g. establishment of plough furrows at the upslope edge of buffer strips)

• Buffers need management.• Important to look after the

upslope leading edge and the first upslope 2m of the buffer, where the bulk of the trapping is done

• Despite wide range of reported efficiencies, buffers have a positive impact and should be implemented widely.

Buffer Strips – some findings (10 experimental sites across the DTC sites)

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Buffer Strips – some findings

• A targeted approach to buffer strips should be adopted rather than a blanket approach.

• Buffer strips should be considered as part of a suite of measures, both in field and edge of field, and not as a last or only resort.

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Treatment trains and not single solutions

No one single solution is going to solve individual or collective problems at a farm or across a catchment – need to:

1. Cut off the source(s); 2. Intercept the

pathway(s) and 3. (as a backstop)

protect the receptor(s)

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The Challenges of addressing scale

• DTC addresses local/farm scale issues – point sources of pollution

• But true diffuse pollution manifests at the wider catchment scale

• Need to address both farm-scale problems and the wider landscape management

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The Challenges of addressing scale

• Standard measures will only achieve required reductions in pollutants with high uptake at the landscape scale

• So… land use change may be required rather than a bundle of the softer measures

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What could be achieved by scaling up up in the Hampshire Avon?

modelling exercise

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Soil managementEstablish cover crops in the autumn

Early harvesting and establishment of crops in the autumn

Cultivate land for crops in spring rather than autumn

Adopt reduced cultivation systems

Cultivate compacted tillage soils

Leave autumn seedbeds rough

Loosen compacted soil layers in grassland fields

Leave over winter stubbles

Use correctly-inflated low ground pressure tyres on machinery

Improved soil management

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Improved soil management

Soil managementEstablish cover crops in the autumnEarly harvesting and establishment of crops in the autumnCultivate land for crops in spring rather than autumnAdopt reduced cultivation systemsCultivate compacted tillage soilsLeave autumn seedbeds roughLoosen compacted soil layers in grassland fieldsLeave over winter stubblesUse correctly-inflated low ground pressure tyres on machinery

N P Sed

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Fertiliser managementUse plants with improved nitrogen use efficiencyFertiliser spreader calibrationUse a fertiliser recommendation system

Do not apply manufactured fertiliser to high-risk areas

Avoid spreading manufactured fertiliser to fields at high-risk times

Use manufactured fertiliser placement technologies

Use nitrification inhibitors

Replace urea fertiliser to grassland with another form

Replace urea fertiliser to arable land with another form

Incorporate a urease inhibitor into urea fertilisers for grassland

Incorporate a urease inhibitor into urea fertilisers for arable land

Use clover in place of fertiliser nitrogenDo not apply P fertilisers to high P index soilsMonitor and amend soil pH status for grassland

Better fertiliser management

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Better fertiliser management

N P

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Manure managementIntegrate fertiliser and manure nutrient supplyIncrease the capacity of farm slurry storesAdopt batch storage of slurryInstall covers to slurry storesAllow cattle slurry stores to develop a natural crustAnaerobic digestion of livestock manuresMinimise the volume of dirty water produced (sent to dirty water store)Minimise the volume of dirty water produced (sent to slurry store)Compost solid manureSite solid manure heaps away from watercourses/field drainsStore solid manure heaps on an impermeable base and collect effluentCover solid manure stores with sheetingUse liquid/solid manure separation techniquesUse poultry litter additivesManure Spreader CalibrationDo not apply manure to high-risk areasDo not spread slurry or poultry manure at high-risk timesUse slurry band spreading application techniquesUse slurry injection application techniquesDo not spread FYM to fields at high-risk timesIncorporate manure into the soil

Better manure management

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Better manure management

N P

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All measures

N

PSed

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My own learning from DTC• Catchments are complex adaptive or self-organising systems -

social, economic and biophysical domains are linked so changes in one can change another; - however, we tend to work in single domains

• Farm businesses are all very different – from £ multi-million investments to subsistence farming

• So, farmers differ greatly in knowledge expertise and attitudes; tenant farmers can be handicapped by their landlords; others by their supply chains

• Understanding the complex systems that underlie agricultural diffuse pollution requires much support for practitioners

• Diffuse pollution won’t be solved farm by farm - there has to be catchment wide co-ordination and collaboration

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Acknowledgements to DTC teams and particularly:Adie Collins – N. Wyke, RothamsteadKevin Hiscock and Andrew Lovett – UEAAlex Inman – Exeter Univ

Thank you for listening

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