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Conservation tillage in the UK

Jim Orson

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% of winter wheat in England established after non-plough tillage

0

5

10

15

20

25

30

35

40

45

1975

1976

1977

1978

1979

1980

1981

1982

1985

1986

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1988

1989

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1991

1992

1993

1994

1995

1996

1997

1998

1999

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2001

2002

2003

2004

2005

2006

2007

2008

Source:

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Average wheat yields (t/ha)

0123456789

1970

1975

1980

1985

1990

1995

2000

2005

2010

USA UK

t/ha

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Min-till does not mean necessarily mean reduced fuel use for primary cultivation

Cost/ha Total time Typical fuelconsumption

Fuel cost/ha

(£) (minutes/ha) (litres/ha) (£ at 52p/litre)

Plough based £75-113 65-150 30-50 £16-26

‘TopDown’ type (working depth 125-150 mm)

£61-78 45-70 38-54 £20-28

‘Carrier’ type(working depth 50 mm)

£59-64 24-59 26-28 £14-15

‘Bioseeder’ for OSR £32 24 16-18 £8-9

Direct drill £21-£31 20-30 8-10 £4-5

Do these comparison take into account timeliness?

If same speed of operation required then ploughing capacity needs to be increased by more than 45%-110%

to be comparable with the ‘TopDown’ resulting in ploughing costing around a total of an additional £45-£120/ha

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The annual % control of black-grass plants needed within the crop to prevent the weed increasing in winter cereals

%

Tine/disc (5cm) 99%

Tine/disc (10cm) 98%

Tine/disc (20cm) 97%

Tine/disc (20cm) + cultural (50% less heads)

93%

Plough 90%

Plough (20-25cm) + cultural (50% less heads)

80%

Source: Moss et al., 2010

Comment faire lever les adventices ?

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50

100

150

200

250

Repousses de blé1er déchaumage

Ray Grass1er déchaumage

Véronique de Perse2ème déchaumage

Plantes/m²

Déchaumage 2 cm fin (Horsch SE)Déchaumage 4 cm + Rappui (Semeflex)Déchaumage 5 cm (Smaragd)Chaume nu

Boigneville, été 2007

plus on travaille superficiellement,plus les adventices lèvent facilement

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Black-grass - quicker emergence from shallow incorporation

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19-Sep

30-Sep

08-Oct

16-Oct

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30-Oct

09-Nov

27-Nov

Em

erge

nce

(% s

eeds

pla

nted

)

low dormancy seed surface sown Low dormancy seed 1cm depthHigh dormancy seed surface sown High dormancy seed 1cm depth

Sarah Cook – glasshouse at ADAS Boxworth, sown 4 September 2010

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STAR project – Beccles clay, Suffolk

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STAR project – after 5 yearsYield (relative to ploughing = 100) and cumulative net

margin (£/ha)

RotationWinter Spring Continuous

Plough 100 (£2463) 100 (£1450) 100 (£1079)Shallow (10 cm) 93 (£1885) 88 (£1383) 97 (£1046)Deep (20 cm) 97 (£2563) 95 (1427) 94 (£870)

Average cumulative margin (£/ha)£2345 £1428 £1088

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0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Depth (inch)

Meg

apas

cals

Annual plough Managed approach Shallow tillage Deep tillage

Soil penetrometer readings - 2011STAR project - Effect of cultivation

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0

0.5

1

1.5

2

2.5

3

1930 1940 1980 2006 2006

Soil stress (Bar) at 0.4 m depth

14 fold increase

7 fold increase

Soils are now over-stressed!?

12 t

Source – Tim Chamen, based on Koolen et al., 1992

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Cultivated soils susceptible to compaction – even under very dry conditions

Colworth – autumn 2009

Chicksands – autumn 2009

August 2010

August 2010

Tim Chamen – PhD thesis

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More than one reason to achieve sustainable shallow tillage

Energy inputs GHG emissions

GJ/ha (% of total chain) Kg C02eq/ha (% of total chain)

Diesel 4.7 (28%) 356.6 (11%)

N fertiliser 7.5 (46%) 2,528.6 (81%)P fertiliser 0.7 (4%) 29.1 (1%)

K fertiliser 0.4 (2%) 21.0 (1%)

Pesticides 0.6 (4%) 10.8 (0.5%)

Seeds 2.5 (16%) 160.4 (5%)

Total 16.0 3,106

Source: Rickeard et al., 2004

A climate friendly

technology

A climate unfriendly technology

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Sustainable shallow tillage

• Can a virtuous circle be created:– need to move less soil – shallow tillage with lighter tractors should result in

higher organic matter content in the disturbed layer (leading to improved surface soil tilth) and less soil damage at depth

– but the impact of wheels/tracks need to be avoided; can improvements in tyres/tracks and/or precision techniques (controlled traffic) provide a way forward?

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Initially carbon losses are reduced by the introduction of shallow tillage but after a few years the organic matter formed from crop residues becomes concentrated in the cultivated layer and so carbon losses not much less

than ploughing

Comparisons of tillage effects are often made on C concentrations in the top 15 cm (or less). This is not satisfactory as it does not account for differences in soil bulk density and placement of OM below 15 cm.

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Soil amendment research

No compost Compost

pH 7.5 7.7N 10.9 13.7P 24.3 32.7K 122.0 198.5Mg 28.5 49.0OM % 1.9 2.3

4.004.505.005.506.006.507.007.508.008.50

Spring break Spring break + cover crop

Yiel

d (t/

ha)

- compost + compost

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Water infiltration – 2011NFS cultivation study

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Strip Tillage

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Strip tillage – great for winter oilseed rape

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Not so good for sugar beet

NIAB Innovation Fund

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Conclusions

• Shallow tillage is not sustainable on the majority of UK the arable area

• Will improved ‘soil fertility’ and better tyre/track technology and/or controlling traffic and/or strip tillage provide a way forward?