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Alleviating Compaction
This is for only 1 tractor and trailer of a pair:
Field area is 14.8 ha
Tractor wheel marks total 20km (1 tractor)
Pea Harvest:Tractor and trailer GPS Log
Ploughing on trafficked and non-trafficked fields
System kN/sq.m kJ/ha
Trafficked 107 117
Non-trafficked 42 47
After: Chamen, Silsoe Research Institute
Specific resistance and energy requirements
No traffic Trafficked
Harrow 25 Spring tine 57
Drill 27 Power Harrow 108
Roll 27 Harrow 29
Drill 31
Roll 30
TOTAL 79 255
After: Chamen,SRI
A 3.23 x INCREASE in ENERGY
Traffic control effects on field operations and
energy (MJ/ha) needs
Compaction:- Tyre load and inflation pressure
• Pressure = Weight/Area
• Area = Weight/Pressure
• Weight = Pressure x Area
W
P
A
N.B. Ignoring carcass effects
Carcass stiffness effects (approximate)
Tractor tyre + 1.5 psi
Combine tyre + 7.0 psi
Low ground pressure tyre + 0.7 psi
Effects of load, inflation pressure and speed
Weight Low Weigh Low Weight High Weight High
Pressure High Pressure Low Pressure Low Pressure Low
1
112
2
2
2
33
3
34
Pressure distribution1
Pressure has the greatest influence on the degree of
compaction and load influences the depth of soil compaction
LOW SPEED HIGH SPEED
Surface effects
Sub surface effects
0.6m
Subsurface effects - pans
Sub-soiling
benefits are
limited to:-
* sandy soils
with
* spring sown
crops
in
* years of
moderate to
severe drought
After: Soane, Godwin &
Spoor, 1985
2 Problem areas
1. Re-compaction of loosened soil during
crop establishment
2. Further re-compaction of settled soil at
harvest time
Which resolve into :
1. Size
2. Weight
3. Pressure
Harvesting
Heavy machines and getting heavier?
Gross weight of a range of vehicles
0
10
20
30
40
50
60
70
Drills
Spra
yer
Spre
ader
Tract
or
Com
bine
Traile
r
Tanke
r
Truck
Bee
t Har
vest
er
Pea
Har
vest
er
Gro
ss w
eig
ht,
to
nn
es
After: Erickson et al 1974
0
20
40
60
80
100
120
Drills
Spra
yer
Spre
ader
Tract
or
Com
bine
Traile
r
Tanke
r
Truck
Bee
t Har
vest
er
Infl
ati
on
pre
su
re,
psi
Tyre inflation pressure of a range of vehicles
After: Erickson et al 1974
Options for reducing compaction
Options
Controlled traffic Traffic reduction Uncontrolled traffic
Permanent tracks Temporary track
Linked operations
Low mass Medium mass High mass
Gantries
Extended track widths
Wide wheels
Load reduction
Lower inflation pressure
New wheel/track systems
Restricted?
Tramlines
After: Soane, 1981
Tread lightly - the alternatives
Typical Weight = 18tons / 40,000lbfs Power = 375 hp
Total contact area = 3,920 in2 6426in2
Average Contact Pressure = 10.2 psi (MINIMUM) 6.2 psi
30 in66 in
4 pairs of equal size dual tyres .v. Rubber tracks
After: Goodyear & Caterpillar, 2001
Tyre selection
Fit the largest section/diameter tyre at the
lowest safe working pressure
Trailers can be the main
culprit
Terra (low ground pressure) tyres
Duals
Dual tyres on combine & tractor + chaser wagon
Narrow section
Go for diameter- large contact patch
Beet Harvester ~ Tyre Configuration
55 tonnes
55 tonnes
Central tyre inflation systems are
available for conversion from field
to road to field inflation pressures
800-70x38
@ 1.6-1.9 bar
Inflation pressures
Compaction issues
25 tonnes
20 + tonnes
7 bar
2 bar (1 bar better)
Laboratory studies
3 tyre sections (500/65-22.5, 700/50-26.5, 800/40-26.5)
3 inflation pressures(13, 23, 33 psi)
3 soil bearing capacities
1 weight (4.5 tonnes)
200mm
Rut
Depth
Reduced Tyre Pressures and Central TyreInflation systems
Inflation Pressure
Field/Low speed
13 psi
140 mm
N.B. Lower pressure tyres would
need Central Tyre Inflation System
to enable safe road use
Road/High speed
33 psi
Initial density 1.25 g/cc
Effect of inflation pressure on soil strength
Stranks, Dresser and Godwin, 2004
Penetration resistance, MPa
Depth
, cm
Rubber Tracks
Effect of track weight distribution
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
Time, seconds
15
45
30
Pressure, psi
48%
Balanced
Original
Rydberg,2003
18.5t Challenger on 2 x 2.1m2 rubber
tracks average contact pressure 6.5psi?
Compaction alleviation - Rubber tracks
28 tonnes
32 tonnes
Extra cost £1/ha over the
working life of the
combine
Track and Tyre Evaluation
0 - 14t 0 - 12t
23/03/2009 Land Rover Short Course –
Godwin32
+/- 2mm
Deformation measurement
23/03/2009 Land Rover Short Course –
Godwin33
Soil deformation
0 200 400 600 800 1000 1200 1400
1000
900
800
700
600
500
400
300
200
Width (mm)
Depth
(m
m)
Tyre Track
0 200 400 600 800 1000 1200 1400
1000
900
800
700
600
500
400
300
200
Width (mm)
Depth
(m
m)
0
100
200
300
400
500
600
700
-20 0 20 40 60 80 100 120
Deformation (mm)
De
pth
(m
m) 900 followed by 700
900 followed by 500
Track followed by 700
Track followed by 500
Dominator
LSD
30 t
33 t
Displacement (mm)
11 t
Compaction reduction
- Rubber tracks
23/03/2009 Land Rover Short Course –
Godwin35
Track pressure distribution
-0.5
0
0.5
1
1.5
2
8.5 9 9.5 10 10.5 11 11.5 12 12.5
Time (s)
Pre
ss
ure
Track position
Pre
ssure
Sensor @ 250mm
Ceramic pressure
transducer
Pressure from a Truck tyre: 5 t, 7bar
-1
0
1
2
3
4
5
6
7
8
9
10
14 15 16 17 18 19 20
time (s)
pre
ssure
(bar)
Max Pressure = 9.27 barSensor @ 250 mm depth
0
1
2
3
4
5
6
7
road harvester rear
tractor
harvester rear
tractor
track harvester dual harvester track human
Pre
ss
ure
(b
ar)
5t, 7bar 10t, 2bar 10t, 1bar 12t 5t, 2bar 2t, 1bar 5t, 1bar 5t walking
2t, 2bar 2t, 1bar
Effect of wheel/track system on pressure at
250mm
-700
-600
-500
-400
-300
-200
-100
0
0 1 2 3 4 5 6 7
Track 5t
Road 5t-7bar
Tractor 2t-1bar
Tractor 2t-2bar
Dual 2t-1bar
Harvester 10t-2bar
Harvester 10t-1bar
Harvester 5t-1bar
Harvester 5t-2bar
Track_12t
Pressure (bar)
De
pth
(m
m)
Effect of ground drive and depth on soil pressure
• Simple concept
• Standardise wheel centres
• Industry resistance to
change in broad acre crops
• Narrower track solutions
under investigation
Controlled Traffic Systems:
<10% surface wheeled
After: Tullberg et al (2003)
Tillage and traffic effects on runoff
Wheeled Controlled Traffic
mm % mm %
Conventional Tillage 322 100% 266 83%
Zero Tillage 282 88% 166 52%
Results from Queensland
1354 mm rain in 2 years
After: Tullberg, 1996
Plot 7 Zero Traffic Plot 8 Normal traffic Plot 9 Zero traffic +tracked combine
Yield from Low Ground Pressure Trial Cranfield University and TAG
After: Phillpot, Stobart, Mouasen and Godwin, 2008
12. 52 t/ha 0.84t/ha 12.14t/ha
Effective subsoiling
Limited evidence of crop response to deep loosening in
UK soils unless for spring sown crops in sandy soils in
years with low rainfall
Tramline management
Runoff
Chisel or
side inclined
tines on
upper
tramline
wheelmark
only
Cross drain with mole plough
OR
Conclusions
• Do all you can to reduce load and pressure
• Spread load where possible
• Keep compaction as shallow as possible – easier
and cheaper to remove
• Minimise random traffic
• Work in sensible patterns
• If damage occurs repair it as soon as is
practicable
• Follow the soil loosening advice given earlier
From:
Cross Compliance
Guidance for Soil
Management
Defra 2005
Practical Aspects
Soil disturbance from
subsoilers
& track and tyre systems.
Whole Machine
Comparison
0
100
200
300
400
500
600
700
-15 5 25 45 65 85 105
Deformation (mm)
Depth
(m
m)
900/10.5/1.9
900/10.5/1.9-
700/4.5/1.0
900/10.5/1.9-
500-70/4.5/2.3
T12
T12-700/4.5/1.0
T12-500-
70/4.5/2.3
LSD
Track system Tyre system
Case study
Considering the farm given in the Appendix
a. What soil problems may arise on the different soils requiring tillage to
alleviate and during the actual tillage operations? Indicate the likely
nature, extent and depth of the problems where appropriate, relating
them to different working conditions.
b. What tillage systems would be appropriate for establishing cereals
after harvest? Indicate likely working depths, equipment needs and
potential workrates.
c. Considering tyres/tracks and field operating procedures, indicate the
opportunities which would be available to reduce soil problem and
hence future tillage needs
i. with existing equipment
ii. when replacing equipment
APPENDIX
Soil types:Chalky and sandy soils
Area: 950 ha (400 ha cereals)
Soils: chalky soils on slopes, a shallow clay cap
Loamy sand/sandy loam soils on flat areas, some with inherent high water table
Crops/succession: sugar beet, potatoes, vegetables, cereals
Root crops irrigated
Cereals follow both root crops and cereals
Root crops usually follow cereals
Equipment weights and pressures:
Tractors:
Wheel: 150 – 190 hp 9 tonnes
Ploughing tractor 18 – 20 psi
Seedbed work, duals 10 psi
Track: Cat 55 for most seedbed work 6-7 psi
Trailers:
Tandem axle
11 tonne 45 – 50 psi
14 tonne 45 – 50 psi
17 tonne Potato boxes 60 psi
Combine:
25 tonne 30 – 35psi
Sugar beet harvester:
6-row, full tank 35-40 tonne 40 – 45 psi
Sprayer:
3600 l capacity tank, terra tyres 9 psi, narrow tyres 35-40 psi
Operating procedures
APPENDIX
Soil types: Chalky and sandy soils
Area: 950 ha (400 ha cereals)
Soils: chalky soils on slopes, a shallow clay cap good soil water holding capacity / tramline erosion/ runoff
Loamy sand/sandy loam soils on flat areas, some with inherent high water table capping/slumping
Crops/succession: sugar beet, potatoes, vegetables, cereals beds/controlled traffic consider drainage
Root crops irrigated capping
Cereals follow both root crops and cereals could be damaged after beet harvest/deep loosen-as and when
Root crops usually follow cereals
Equipment weights and pressures:
Tractors:
Wheel: 150 – 190 hp 9 tonnes
Ploughing tractor 18 – 20 psi consider move to tracked tractor/reduced tillage for cereals
Seedbed work, duals 10 psi
Track: Cat 55 for most seedbed work 6-7 psi could reinvest in larger version next time around to increase work rates
Trailers:
Tandem axle
11 tonne 45 – 50 psi
14 tonne 45 – 50 psi - larger tyres/lower pressure/chaser bins
17 tonne Potato boxes 60 psi
Combine:
25 tonne 30 – 35psi -rubber tracks??
Sugar beet harvester:
6-row, full tank 35-40 tonne 40 – 45 psi contractor machine with larger tyres
Sprayer:
3600 l capacity tank, terra tyres 9 psi, narrow tyres 35-40 psi improve tramline management
Operating procedures
Large fields, harvesters unloading into trailers within fields. – chaser bins
John Dale
Seed Hawk Tines
•1+2 Seed Location
•3 Packed Surface
•4 Tungsten Carbide Cutters
•5 Pneumatic Packer / Depth Wheel (good mud release)
•6 Seed Coulter (½" (12.5mm) wide)
•7 Seed Drop Tube
•8 Seed Coulter
•9 Trip plate
•10 Chain
•11 Depth Lock Bolt
•12 Depth Gauge (accurate to 1/8") (3mm)
•13 Hanging Bracket
•14 Hydraulic Cylinder
•15 Placement Arm
•16 Seed Drop Tube
email > info@daledrills.com tel > 01652 653326
Practical application for field vegetables
After: Vermuelen (2006)
Controlled traffic system for vegetable production using RTK-GPS and
300 mm wide rubber tracks.Track positions are at 3.15 m centres
RTK-GPS enables < +/- 20 - 30 mm positional error.
Issues of repeatability and cost are being addressedAfter: Chamen (2007)
Dual-Trac for narrower track width tractors
After: Shaw and Chamen 20053 m 2 m
24 m chemical application
8 m harvester
8 m seed drill
•Assisted by “Autosteer”
•John Deere tractors with “independent
link suspension for the front axle”
•Also use for harvesters
After: Shaw and Chamen (2005)
Moore Unidrill
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