Some Learning from the Demonstration Bob Harris Test Catchments - - PowerPoint PPT Presentation

Some Learning from the Demonstration Test Catchments Programme (DTC)

Bob Harris

With thanks to Adie Collins, Kevin Hiscock, Andrew Lovett, Alex Inman and many others

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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

• thers...

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 2 2014 – 2018 Phase 3 2018 – 2019

The DTC programme aims 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
• f 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 9

Rainfall Response: Phosphorus & Sediment

Surface runoff initiated

Rapid return to pre-event conditions 10

Interrogating the evidence

Important to monitor all nutrient fractions, to fully understand the sources/pressures impacting on ecosystems and provide sensitivity for detecting post-measure changes

0.5 1 1.5 2 2.5 3 3.5 4

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

Annual load (kg P ha-1) Particulate phosphorus Dissolved organic phosphorus Soluble reactive phosphorus 5 10 15 20 25 30 35 40 45

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

Annual load (kg N ha-1) Particulate organic nitrogen Dissolved organic nitrogen Total oxidised nitrogen

2012 2013 2016 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

• f 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

• ther 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

• f 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 fencing

Cost: 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 P Cover crop Block L Cover crop Block 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 2013

Winter Cover Crops

Block J Block P Block L

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Field Drain Monitoring

Winter Cover Crops

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

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Economics: Farm returns

Winter 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 L

Fallow Cover crop Cover crop

Gross output beans: Yield (t/ha) Output at £260/t (£/ha) 5.80 1334 6.55 1435 6.24 1506 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 85 748

Margin (£/ha) 745 731 758

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Sediment: Silt traps

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Installation

Roadside 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 kg Damage cost: £392 Phosphorus retained: 11.6 kg Damage cost: £148 Nitrogen retained: 29.7 kg Damage cost: £13 Total mitigated damage cost: £553 Trap cost: £3,400 Annual 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: £12,790 Total Nitrogen: £430 Sediment: £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

• r 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 management

Establish 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 management Establish 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

N P Sed

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Fertiliser management Use plants with improved nitrogen use efficiency Fertiliser spreader calibration Use 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 nitrogen Do not apply P fertilisers to high P index soils Monitor and amend soil pH status for grassland

Better fertiliser management

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Better fertiliser management

N P

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Manure management Integrate fertiliser and manure nutrient supply Increase the capacity of farm slurry stores Adopt batch storage of slurry Install covers to slurry stores Allow cattle slurry stores to develop a natural crust Anaerobic digestion of livestock manures Minimise the volume of dirty water produced (sent to dirty water store) Minimise the volume of dirty water produced (sent to slurry store) Compost solid manure Site solid manure heaps away from watercourses/field drains Store solid manure heaps on an impermeable base and collect effluent Cover solid manure stores with sheeting Use liquid/solid manure separation techniques Use poultry litter additives Manure Spreader Calibration Do not apply manure to high-risk areas Do not spread slurry or poultry manure at high-risk times Use slurry band spreading application techniques Use slurry injection application techniques Do not spread FYM to fields at high-risk times Incorporate manure into the soil

Better manure management

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Better manure management

N P

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All measures

N P Sed

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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, Rothamstead Kevin Hiscock and Andrew Lovett – UEA Alex Inman – Exeter Univ

Thank you for listening

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