www.adas.co.uk

Greenhouse gases – How to reduce emissions

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ken.smith@adas.co.uk

Ken Smith, ADAS Wolverhampton

Likely future UK climate

Higher temperatures� 1.5-3.5°C higher by 2050s� 3.0-4.0°C higher by 2080s

More summer droughts� 20-40% less rain by 2050s

More winter rainfall� 10-25% more by 2050s

Note there is a high degree of uncertainty associated with theseprojections

Higher CO 2 concentrationsMore extreme weather eventsSea levels to rise by 36cm in London by 2080s?

Climate change - gases

What causes climate change?� levels of greenhouse gases (GHGs) in the atmosphereAct as blanket keeping planet warm

What gases are of concern in agriculture?Nitrous oxide – 298 x more potent than CO2

• Manufacture artificial N• Application of organic & artificial N• Livestock manures

Methane – 25 x more potent than CO2

• Ruminant livestock

Carbon dioxide (CO2)• Diesel fuel use• Electricity• Other fossil fuels

Methane

NitrousOxide

CarbonDioxide

GHG emissions reduction targets

Climate Change Act 2008 - UK domestic ambition (from 1990)

• 23% reduction by 2012• 29% reduction by 2017

• 35% reduction by 2022

• 50% reduction by 2027

Ultimate goal• 80% reduction by 2050• Equivalent to 155.6 Mt CO2e

Agriculture contribution• 3Mt CO2e per year against 2008

baseline

Agriculture ’s contribution

1% carbon dioxide

37% methane

79% nitrous oxide

Agriculture = 9% UK GHG emissions

Greenhouse Gas Action Plan

Voluntary industry initiative to reduce emissions

15 on-farm actions targeting • � management crop nutrients & soils

• � manure and slurry handling practices• � animal health, nutrition & breeding

• Protecting and enhancing carbon stores

• � fuel and energy management (renewable energy)

Benefits from adopting best nutrient management practices

Maximise or increase farm profitsImprove ‘green’ credentials by minimising pollution

Possible ‘earned recognition’ if farm shown to be low pollution risk• Reduced record-keeping burden

• Less inspection

Minimise risk of non-compliance• meeting Cross compliance requirements• obtaining Single Farm Payment

• complying with Farm Assurance Schemes for produce sales

Ammonia emissions from UK agriculture

Inventory of Ammonia Emissions from UK Agriculture - 2009

Housing27%

Manure application

22%

Manure storage

13%

Hard standings

9%

Grazing/outdoors

13%

Fertiliser application

16%

GHG emissions from UK agriculture(% on CO 2e basis)

Defra (2007)

10%

52%38%

Nitrous oxide

Methane

Carbon dioxide

From: 2008 GHG Inventory for England, Scotland, Wales and

Northern Ireland

Checklist for good nutrient management

1. Choose appropriate cropping

2. Plan manure applications

3. Assess soil type and improve structural conditions

4. Understand and comply with relevant regulations and assurance scheme requirements

5. Adopt the Nutrient Planning cycle

6. Buy most appropriate fertiliser(s)

7. Accurately apply fertilisers and manures

8. Keep records as aid to future planning and decisions

Know and allow for soil nutrients pH, P, K, Mg

• Wide variation in soil nutrient Indices depending on soil type and field history

• High Indices possible– Lots of manure applied (e.g.

close to livestock buildings)

– Potatoes in rotation (high P)– Clay soils (high K)

• Low Indices possible– Sandy soils (low K)

– Cut grass (low K)– History of low nutrient use

• Soil analysis every 4-5 years is essential

Distribution of soil P index values

Distribution of soil K index values

Correct nitrogen use can double crop yields

0

80

0 40 80 120 160 200 240 280 320

Nitrogen applied (kg/ha)

Yie

ld (

t/ha)

0

10

Nitr

oge

n le

ach

ed (

kg/h

a)

Rapid response

The economic optimum rate of nitrogen

Biological maximum yield

Penalty at high rates

Nitrate concentrations in over-winter drainage following different previous crops (1990-2006)*

*(Source: Defra NVZ AP consultation document D3, 2007)

N requirement for potatoes1. Estimate N supply from soil

• Field Assessment Method (N index)

• Sampling & analysis

2. Crop variety group?

3. Anticipated season length?

4. Assess crop N requirement

5. Fine tuning? Considering….

• Canopy development, defoliation, skin set?;

• Planting conditions, adj. season length;

• N timing, pest/disease?

Nitrogen use on maincrop potatoes grown in Britain between 1990 and 2009. Source: BSFP

Phosphate use on maincrop potatoes in GB 1990 and 2009. With recommended P rates at index 1, 2 and 3.

(Source: BSFP)

Variety group 1 2 3 4

% total crop area 10 27 39 5 Notional N rec (<60day season)*

100-140 80-120 60-100 N/A

Notional N rec (>120day season)*

N/A 190-250 150-210 100-180

* Assuming SNS index 0 or 1

Percent of potato crop area by variety group & notional recommended N rates ( Potato Council, 2010)

(Ave N use mc potatoes - 168 kg/ha N, BSFP, 2010)

Know and allow for soil nutrientsSoil N Supply (SNS)

• Field Assessment Method (FAM)– Based on soil type, rainfall and cropping

history– Provides a good guide but take account of

farm experience

• Measuring SMN– More worthwhile if likely SNS is higher than

120 kg N/ha (Index 4 and over)• Organic manures regularly used• Grass ploughed out (not year 1)

• After field vegetables leaving high-N residues

– Spring (0-90cm) or autumn (0-60cm) sampling, not within 2-3 months of a nitrogen application

– 10-15 sub-samples, carefully mixed– Sample kept cool (not frozen) and sent to lab

for analysis within 3 days

FAM - Excess Winter Rainfall

Long term ‘Average’(whole winter to 30 March)

To February 2012

Proportion of cropping area receiving manure applications in recent years

0

10

20

30

40

50

60

70

80

2002 2003 2004 2005 2006 2007 2008

% c

rop

are

a r

ece

ivin

g m

an

ure

s

Winter wheat Spring barley

Winter barley Potatoes (main)

Winter OSR Grassland

(Source: BSFP, 2002-2008)

Impact of manure use on fertiliser nitrogen input –maincrop potatoes (Source: BSFP 2008)

0

2040

6080

100

120140

160180

200

2001 2002 2003 2004 2005 2006 2007 2008 2009

Ove

rall

N u

se k

g/ha

no manure

with manure

Impact of manure use on fertiliser inputs –maincrop potatoes (Source: BSFP 2010)

N P2O5 K2O Manure rate for 250 kg/ha N (t/ha)

Est. nutrient allowance

24 48 65 -

Supplied by FYM (t/ha)

40 25 8 42

Supplied by P litter (t/ha)

2 3 4 8

(kg/ha)

Fertiliser value of organic manures

* Assumes spring surface applicationN = 92p/kg; P2O5 = 95 p/kg; K2O = 56 p/kg

Manure type (dry matter)

App rate (m3or t/ha)

Crop available N (kg/ha)

Total P2O5

(kg/ha)

Total K2O

(kg/ha)

Value (£/ha)*

Pig FYM (25%) 35 25 210 280 377

Cattle slurry (6%)

50 46 60 160 188

Broiler litter (60%) 8 72 200 144 336

Biosolids digested cake (25%)

20 33 360 12 378

Make the most of organic manure nutrientsCreate a farm manure application plan

1. Select fields/crops that will benefit most from the nutrients and organic matter applied

2. Determine the supply of organic manure nutrients

3. Choose best application equipment

4. Choose best application timing and incorporation

5. Reduce application rates of manufactured fertiliser

Manure nutrient content

• ‘Typical figures’– Fertiliser Manual– PLANET

• Analysis– Laboratory

• Wet chemistry• NIRS

– On farm• Slurry hydrometers• N meters (Agros/Quantofix)

Cattle slurry, total nitrogen

0

2

4

6

8

0 5 10 15 20

Dry matter (%)

Tot

al N

(kg

/t FW

)

Range of N content at

6% DM 1.2 – 4.5 kg/m3

Fertiliser Manual ‘standard’ N 2.3 kg/m3 at 6% DM

It should be remembered that…

• The costs of manure handling and application are likely to be similar whether done badly…or well

• Risks of over application;– Nutrient losses to water– Nutrient losses to air– Lost £££

• Risks of under application;– Reduced crop yield– Lost £££

y = 0.25x +1.3R2 = 0.61

0

1

2

3

4

5

0 2 4 6 8 10

Dry matter (%)

Tot

al N

(kg

/t)

Analysis of slurry samples from a dairy farm in Oxfordshire (33 samples, 2002-2011)

Further reasons for manure analysis

Livestock manure N efficiency values for N max compliance in NVZs

Manure type Crop avail N (% Ntotal) pre 1st Jan 2012

Crop avail N (% Ntotal) from 1st Jan 2012

Cattle slurry 20% 35%

Pig slurry 25% 45%

Poultry manure/litter

20% 30%

Other manures 10% 10%

Rapid on farm slurry testing

• Slurry hydrometers• Nitrogen meters

– Quantofix– Agros

Sampling of solid manures?

Chemical analysis of NIRS calibration samples – homogenisation procedure

Quick freezing in liquid nitrogen and homogenisation

Total N (g/kg DM) (Poultry, Pig & Dairy manures)

Manure analysis (total N) - benefit of sample homogenisation

y = 0.9272x + 1.6281R2 = 0.3305

0

10

20

30

40

50

60

0 10 20 30 40 50

Analysis 1

Ana

lysi

s 2

y = 0.9836x + 0.4645

R2 = 0.9973

0

10

20

30

40

50

60

0 10 20 30 40 50 60

Analysis 1

Ana

lysi

s 2

(a) before homogenisation (b) after homogenisation

Scanning of manure samples and estimation of nutrient content by NIRS

NIRS calibration for total N

Total nitrogen ( g/Kg ) Calibration fit.

R2 94.78 RPD 4.38

y = 0.9478x + 0.331

R2 = 0.9478

-1

4

9

14

19

24

29

34

39

44

49

0 5 10 15 20 25 30 35 40 45 50

True

NIR

S fi

t

NIRS analysis

• AHDB information sheet• NIRS analysis offered by

Eurofins;• Pig/cattle FYM & slurry, biosolids• DM, total N, NH4-N, P2O5, K2O,

SO3

• £26.40• On-line ordering;

www.agriculturaltesting.co.uk

Sampling strategy - manure N application rate** & associated variability* (cv%)

0

50

100

150

200

250

0 5 10 15 20

Sample number

Man

ure

N r

ate

kg/h

a

0.0

5.0

10.0

15.0

cv%

Manure N rate

cv% (means)

(* Simulated variability for 3 replicates - cv%) (Tidy heap)

(** based on FYM N content and notional application rate 20t/ha)

0

50

100

150

200

0 5 10 15 20

Sample number

Ma

nu

re N

ra

te k

g/h

a

0.0

5.0

10.0

15.0

CV

%

Manure N rate

cv% (means)

Sampling strategy - manure N application rate** & associated variability* (cv%)

(* Simulated variability for 3 replicates – cv%) (Untidy heap)

(** based on FYM N content and notional application rate 20t/ha)

Nutrient management tools

0

1

2

3

4

5

6

7

8

9

10

0 50 100 150 200 250 300

Nitrogen supply (kg/ha)

Gra

in y

ield

(t/h

a)

Manure N supply

Fertiliser N supply

Soil N supply

Target N

Use manures to supply up to 40 - 50% of nitrogen recommendation

Nitrogen fertiliser types

Ammonium nitrate (33.5-34.5% N)Most common, straight N or NPK compound

Reliable and rapidly availableSafety hazard

Liquid urea ammonium nitrate (UAN, 37% w/v)

Common in arable as easy handling and accurate

Urea granules (46% N)Often cheap but high risk of ammonia loss

Agrotain urease inhibitor reduces ammonia loss

0

5

10

15

20

25

30

Urea Urea+Ag AN

Am

mon

ia lo

ss (

% N

app

lied)

Source: Chambers & Dampney (2009).

Fertiliser Spreaders –maintenance, calibration, use

13%Serious >20

8%Poor – can be improved15 - 20

6%Respectable10 - 15

4%Excellent<10

Increase in Nitrate LeachedSpreader Condition%CV

Spread Pattern Before Calibration

0

2

4

6

8

-38 -34 -30 -26 -22 -18 -14 -10 -6 -2 2 6 10 14 18 22 26 30 34 38

Spread Pattern After Calibration

0

2

4

6

-38 -34 -30 -26 -22 -18 -14 -10 -6 -2 2 6 10 14 18 22 26 30 34 38

Spread Pattern Before Calibration

0

2

4

6

8

-38 -34 -30 -26 -22 -18 -14 -10 -6 -2 2 6 10 14 18 22 26 30 34 38

Spread Pattern After Calibration

0

2

4

6

-38 -34 -30 -26 -22 -18 -14 -10 -6 -2 2 6 10 14 18 22 26 30 34 38

Spreaders – maintenance, calibration, use

Area of overlap

Area of overlap

Green manures

� Cover crop grown primarily to add nutrients and organic matter to soil

� Typically, autumn - late winter (4 months?), destroyed while still green

Crop N – 75kg/haSMN – 62kg/ha

Oilseed rape + manure treatments (ADAS Boxworth, sampled 21 November 2008)

Autumn, post emergence pig slurry applied 29 Sept (173kg/ha N)

Nil nitrogen

Crop N – 8kg/haSMN – 31kg/ha

Green manures: N uptake

� Species and over-winter weather influence N retention by green manures

Green cover: N uptake

� NO3 loss is smallest (& N uptake greatest) when cover established early

� Cover crops can reduce NO 3loss over-winter by 50 kg/ha N

Potato Council Green Manures Grower Field Trial (pre - potatoes, spring 2012)

plot crop target sowing date

seed rate kg/ha

seedbed fert. kg/ha N

1 rye early Sept 180 -

2 Natural regeneration

n/a n/a -

3 mustard (std) mid Aug 20 -

4 bare stubble n/a n/a -

5 oil radish mid Aug 25 50

6 caliente mustard mid Aug 8 50

(WB Daw & Son, Rugeley, Staffs)

Green manures grower field trial LH – stubble; RH – mustard (1st Feb 2012)

Green manures: promoting greater resource efficiency

Green Manures …

� take up c.30-50 kg N/ha otherwise leached over-wint er

� conserve water and nutrients otherwise lost from la nd

� reduce risk of erosion, loss of topsoil and water p ollution

� can supply available N and soil aeration benefits w hen used prior to spring-sown crops

� suppress weeds; some species discourage pests &/or diseases

� species choice, management methods and ELS points can keep costs down and minimise limitations

� establish by mid-Sept; destroy mid-Dec to mid-Feb

Summary

Benefits of good nutrient management• Business profitability• Environmental impact

• Principals of good nutrient management• Assess crop nutrient requirements• Allow for soil nutrients• Allow for manure nutrients• Allow for P/K residues from previous years• Apply fertilisers and manures evenly

• Comply with regulations• NVZ & Cross compliance

Potato Council South West Potato Day, 26 April 2012

Reducing greenhouse gas emissions

Thank You!