Cultivations – opportunities,

timing and threats

Dick Godwin

Soil Physical Conditions

Required For Crop Production

• Crop factors

• Soil and water conservation

• Mechanisation requirements

Overview

Tillage alternatives - benefits & limitations

Tillage forces/energy/costs

Crop Yield

Controlled Traffic and Lower Ground Pressure

Weed control

Opportunities, timing and threats

What Tillage?

• Conventional

• Deep

• Shallow

• Minimum tillage

• Direct drill

• No-Till

Considered “Reduced tillage”

Just attempting to plant

directly into the soil

Overall disturbance

to a shallow depth

Perceived benefits of reduced tillage

The main reasons to use min-till are:

To reduce energy consumption

To reduce labour costs

To conserve moisture

To retain plant cover to minimize erosion

Minimise loss of organic matter*

• Each point is very appealing to the farmer who wants to make the best profit margins in terms of field efficiency, fuel economy and work rate. The min-till is also appealing to the farmer who wants to look after the land.

• However, min-till growers are most affected by poor weather conditions, as dry ground conditions are essential for sowing in order to avoid compaction and smearing in the final seed bed.

• For anybody new to min-till, one of the best tools in your tool box for min-till is patience.

• The best advice is to wait until conditions are excellent for sowing. There is little point in sowing a crop (especially winter barley) into a compacted or smeared seed bed.

Independent 07/08/07 * Not in the Independent

Disadvantages

• Crop establishment problems

during very wet or very dry spells

• Weed control problems

• Cost of herbicides, herbicide

resistance

• Risk of increased N2O emissions

and increased dissolved P

leaching

• Reduced reliability of crop yields

• Unsuited to poorly structured

sandy soils

• Unsuited to poorly drained soils

• Risk of topsoil compaction

• Increased slug damage

Advantages and disadvantages of

“No-till” systems.

Advantages

• Lack of compaction below plough

furrow

• High work rates and area capability

• Increased bearing capacity

• Reduced erosion, runoff and loss of

particulate P

• Opportunities to increase area of

autumn sown crops

• Stones not brought to the surface

• Reduced overall costs

After: Soane et al., 2012.

No-till: World wide climatic effects

Analysis of 5,000 observations, indicated on average “No-till”

reduces yields at the global scale, yet opportunities exist for more

closely matching or even exceeding conventional tillage yields.

•For example, yield reductions were minimized when the principles of

crop rotation and residue retention were also practiced.

•In dry climates “No-till” farming performed significantly better than

conventional tillage, due to the higher retention of soil moisture.

•In regions with moist climates “No-till” resulted in yields that were on

average 6 to 9 percent lower than with conventional tillage.

After: Pittelkow, et al., 2014 (Nature - 22nd October) http://news.ucdavis.edu/search/news_detail.lasso?id=11062

Proportion of winter wheat area

using alternative establishment

methods in England

Knight et al 2012

• Soil type - Clays and sands

can both be problems

• Moisture content – plasticity

• Residue levels and condition

• Weed density

Direct drilling constraints in the UK

Provisional

classification for soil

suitability for direct

drilling of combine

harvested crops.

After: Cannell et al., 1978.

50 sites; 214 site x years

Climatic effects:UK

A draft manuscript concluded that after reviewing the work of Soane

(2012) and Cannell (1985) the UK cereal growing areas lie at the

boundary between two European agro-climatic regions: -

• The southern and eastern areas, which are drier and warmer and

direct drilling has shown equal or better yields than conventional

tillage where the barriers to adoption are non-technical, and

• The northern and western areas, where technical problems of

compaction, straw management, reduced soil temperatures and

wetter conditions prevent successful direct drilling.

Cannell, Pidgeon, Davies and Finney - Unpublished manuscript

Likely short and long term trends in

converting from tillage to no-tillage

Increase

Decrease Current position with tillage

Time - years

After: Carter, 1994

Tillage tools

Tine geometry and soil disturbance

After: Godwin, 1974

2 key factors:

1.Rake angle

2.Depth/width ratio

Effect of rake angle on soil forces

UPWARD

DOWNWARD

After: Godwin 1974

Rake angle Direction of travel

Soil surface

Implement face

Effect of implement depth on soil

forces

After: Godwin 1974

Effect of speed on soil forces

0

1

2

3

4

5

0 2.5 5 7.5 10 12.5 15 17.5 20

Speed, km/h

Forc

e,

kN

After: Wheeler and Godwin, 1996

HORIZONTAL

VERTICAL

16% increase for 2x speed

RTF Zero

RTF Deep RTF Shallow

Effect of Tillage on Surface Residues

Effect of tillage/residues on winter wheat yields. Clay soils

TillageTreatment / Site Childerley

t/ha

Childerley

%

Gt. Staughton

t/ha

Gt. Staughton

%

Burnt - 80mm disc 7.92 100 8.25 100

Burnt -150mm plough - - 8.03 97

Burnt - 150mm plough

+roll

7.86 99 8.12 98

80mm Disc 7.13 90 8.18 99

150mm Disc + tines 7.17 90 8.16 99

150mm plough - - 7.99 97

150mm plough + roll 7.71 97 8.19 99

225mm plough - - 7.99 97

225mm plough + roll 7.93 100 8.20 99

Cranfield University/ADAS/Ransomes, Simms and Jefferies, 1987

Implement Depth % Covered

• Mouldboard Plough 150 - 200 mm 90 - 100

• Disc 50 - 75 mm 30

• Disc 50 - 175 mm 70

• Tandem disc 50 - 75 mm 50

• Tines 150 mm 25

• Sweeps 150 mm 10

• Direct drills 25 - 50 mm ~5

Source: ASAE/USDA

Tillage and residue burial

Tillage effects on residues I

From: Illinois Agronomy Handbook

Implement adjustment – clod size distribution and residue levels

no discs,

tines @ 150mm,

plus wings,

no pack.

discs @ 60mm,

tines @ 100mm,

plus wings,

hard pack.

discs @ 60mm,

tines @ 150m,

no wings,

no pack.

discs @ 60mm,

tines @ 100mm,

plus wings,

no pack.

Direct Drill: Disc types

Direct Drill: Tine types

Fertilizer

Seed

Problems with earlier (1970’s)

“disc” drills

Smearedslot

Trappedstraw

Photographs courtesy of Gordon Spoor

Improved disc type drills

StrawSeeds StrawSeeds

DiscCoulter

StrawSeedexitpoint

Disc

Inverted‘T’share

Presswheel

Straw

Seeds

a.b.

c.d.e.

a. ‘Cross slot’ seed placement mechanism. b. Location of seed

relative to the straw.

c. ‘Uni-drill’ seed placement mechanism.

d. Un-modified seed position. e. Modified seed position.

After: Earl and Spoor, 1994.

Winged opener – “Baker Boot”

Baker, Saxton and Ritchie, 1996

Wheat Yields in STAR project 2007 The Arable Group (TAG)

WC - Winter Cropping

SC - Spring Cropping

CWW - Cont. Wheat

AF - Alternate Fallow

AP - Annual Plough

MA - Managed Approach

ST - Shallow Tillage

DT - Deep Tillage

Following Winter

Oilseed rape

Following Winter

Spring beans

Continuous

wheat

Following mustard

cover crop

CV - (Yield) 7.4% LSD - (Yield) 0.97t/ha

0

2

4

6

8

10

12

WC -

AP

WC -

MP(S

T)

WC -

ST

WC -

DT

SC - AP

SC - MA(D

T)

SC - ST

SC - DT

CWW

- AP

CWW

- MA(p

loug

h)

CWW

- ST

CWW

- DT

AF - A

P

AF - M

A(DT)

AF - S

T

AF - D

T

Yie

ld (t/ha

)

Stobart –TAG, 2008

No traffic Trafficked

Shallow plough 13 (£5) Shallow plough 32.5 (£13)

Harrow 7.0 Spring tine 16.0

Drill 7.5 Power Harrow 30.0

Roll 7.5 Harrow 8.0

Drill 8.6

Roll 8.4

TOTAL 22 (£9) 71(£30)

After: Chamen, 1992

A 70% reduction

A 60% reduction

Traffic control effects on energy

requirements and costs (kWh/ha) (£/ha*)

*After: Nix 43rd Edition (2013) c £0.25/kWh

at 65% Tractive efficiency (Innes and Kilgour, 1980)

RTF Deep Tillage RTF Shallow Tillage RTF Zero Tillage

LGP Deep Tillage LGP Shallow Tillage LGP Zero Tillage

CTF Deep Tillage CTF Shallow Tillage CTF Zero Tillage

Winter wheat – 29th May 2013

Zero tillage has a problem in wheel marks in all traffic systems

Smith, E.K., Misiewicz, P.A., Chaney,

K., White, D.R., Godwin, R.J. 2013

Tillage system After: Smith et al., 2014

10% lsd = 0.6t/ha

19% (1.39t/ha) increase in yield.

Tillage v Traffic Study

Winter Wheat Yield Combine harvester results

(Estimated)

No-till

Tillage and Traffic Study

Winter Wheat Yield Hand Sample Results

8.97 8.10

10.72

7.69 7.04

4.34

0

2

4

6

8

10

12

Deep Shallow Zero

Yie

ld t

/ha

Untrafficked Wheelways

Untrafficked yields significantly higher than wheelways (p<0.05)

No-till

Draught force and

fuel consumption

After: Arslan et al 2014

Factors effecting

establishment costs

• Farm size.

– Annual cropped area.

• Average tractor size.

– Power availability.

• Labour availability.

– Can tillage be started before harvest is finished

• Local climate. Number of working days

– Weather conditions in autumn.

Cost comparison of alternative tillage

systems (100 kW/130hp tractor)

After: Vozka, 2007

Cost comparison of alternative tillage

systems (225 kW/300hp tractor)

After: Vozka, 2007

Effect of Tractor & Implement Size

The costs/ha of different sizes (102, 162, 224 kW tractors) of alternative

tillage systems are very similar at optimum working areas.

Mouldboard plough £ 80.33/ha £ +2.48/-1.93/ha

Shallow mouldboard plough is £ 68.85/ha £ +2.02/-1.64/ha

Stubble cultivator is £ 42.05/ha £ +2.02/-1.27/ha

Direct drill is £ 20.76/ha £ +0.89/-0.75/ha

Direct drill with herbicide application £ 43.15/ha £ +0.41/-0.53/ha

After: Vozka, 2007

Black Grass Control by Cultivation

102 108 5 27 72 199

Black Grass Ears/m2

All Drilled12th October 25th September

lsd 8.38%, cv =17.8%

1. A plough anywhere in the system reduces black grass numbers.

2. Use good ploughing techniques. Poor ploughing is of little help as it will not bury the weed seeds.

3. Ploughing for a second year brings resistant black grass seeds back to the surface too soon for effective control.

4. Good ploughing followed by 2 years of direct drilling has reduced black grass and increased yields.

5. Continual direct drilling or shallow min till allows black grass numbers to increase. These systems work well if a good stale seedbed is achieved first and the herbicide chemistry works well.

6. With resistance issues, cultivations are having a greater effect on black grass control than current pre and post–emergence chemical options.

Black Grass Control by Cultivation

Mouldboard plough adjustment

http://www.agrii.co.uk/blog/2013/10/24/the-good-ploughing-guide-from-agrii-and-lemken/

• Work deep enough to bury all weed seeds

• Set skimmers to the correct depth

• Fully invert furrow slice

• Use a slatted mouldboard if soil is sticky

• Use a press to close the furrow

• Ensure the line of draft enables the tractor

to pull effectively with the tractor on the

land when ploughing with larger ploughs.

Opportunities, timing and threats

• Opportunities

– Move to min-till (less risk) or no-till (more risk)? Save time and money

– Integrate with CTF/LGP practices

– Improve yield?

– Save energy

– Improve mechanical weed control

• Timing

– Weather and soil condition

– System capacity (labour availability and machine size)

– Alternative cultivation practice (No-till < min-till < conventional tillage)

• Threats

– Weather

– Weeds

– Capitalisation and cash flow

Conclusions

• To lower cost of tillage and save energy:-

–work shallower, wider and faster

–minimise wheelings and avoid soil structural damage at depth

–modified traditional systems can be cost effective for smaller farms (< c. 250 ha)

• Undertake a thorough financial analysis before finally deciding upon

investment in a reduced tillage system

• Consider controlled and low ground pressure traffic

• Do not throw away the plough - you may still need it for weed control!

N.B. Attempt to achieve the desired soil condition with the

minimum amount of energy, time and investment