This document discusses various topics related to soil compaction from agricultural equipment, including:
- Definitions of soil compaction and the factors that influence it
- Methods for reducing compaction, such as improving soil quality, avoiding wet soils, using larger tires with lower pressure
- How compaction affects soils and crop growth over time
- Measurements of load distribution in soils from different tires and inflation pressures
- Interpreting information provided on tire sidewalls
3. A Management DecisionWhat Is Soil Compaction?
1. Timing of field operations
2. Type of field operations (freq + aggression)
3. Weight and configuration of
equipment
4. Crop selection and rotations
5. Return of organic amendments
6. Soil management We Decide!
4. Let’s Beat
Soil Compaction!
1. Build Better Soils
2. Avoid Wet Soils
3. BiggerTires
4. Lower Tire PSI
5. Use Inflation/Deflation Systems
6. Better Tires
7. More Tires/Axles
8. Less Passes
9. Control Traffic
10. Lower Load Weights
5. Phenomenon of Cyclic Loading
On most implements:
Axle Weight changes dramatically and
continuosly during operation.
Always increasing or decreasing
The change is usually linear
Exception is grain
buggies and
wagons! They get
“pulses” of load!
6. Why is Soil Compaction so
Complicated?
Changing Soil Types,
Slopes
CHANGE
Soil Moisture!
A
B
7. Soil Compaction = Reduced Porosity
pre
impact
post
impact
36 psi
Source: Brunotte et al., vTI
7
10. Why Do We Care About Soil
Compaction?
Results in:
10
*
11. Why Do We Care About Soil
Compaction?Results in:
Decreased water infiltration
Reduced water holding capacity
Reduced root growth and rooting depth
Increased soil erosion
Reduced nutrient uptake
Increased input cost
Reduced yield
Reduced water and soil quality
11
*
12. Håkansson I (2005) Machinery-
induced compaction of arable
soils, incidence – consequences
– counter-measures. SLU,
Uppsala, Reports from the
Division of Soil Management. No.
109, 154 pp.
Compaction
Compaction
Compaction
Compaction
Compaction
Compaction
Compaction
Surface Compaction
https://pub.epsilon.slu.se/5517/1/hakansson_i_101206.pdf
13. Single Subsoil Compaction
Event Consequences
Year after compaction
Relativeyield(%)
80
85
90
95
100
105
0 2 4 6 8 10 12 14
Håkansson I (2005) Machinery-induced compaction of arable soils, incidence – consequences – counter-measures. SLU,
Uppsala, Reports from the Division of Soil Management. No. 109, 154 pp.
Compaction
14. Depth and Impact of Soil
Compaction
Shearer and Fulton,OSU,
CompactionSmart2016
16. Everything is a Spring…
We can measure soil pressure to compare
tires on different vehicles
16
17. What are the loads on soil?
Axle weight, tire pressure, contact area,
length of contact are all factors.
• Increased soil
moisture
increases depth
of compaction.
17 *
18. What are the loads on soil?
6 inches
12 inches
20 inches
18
19. Compaction Action! And Elgin and Dundas
Equipment fully loaded: maximum risk
Equipment weighed
Tire pressure set based on weight, speed
Select equipment tested at road inflation
pressure and field pressure
19
90. Tire Load and Soil Stress
Location Normalized to 40 psi and 6-8 Ton Tire Load
90
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 2 4 6 8 10 12 14 16
NomralizedSoilPressure
TireLoad (Tons)
6" Normalized Stress
12" Normalized Stress
20" Normalized Stress
Linear (6" Normalized Stress)
Linear (12" Normalized Stress)
Linear (20" Normalized Stress)
91. Tire Pressure and Soil Stress
Location Normalized to 40 psi and 6-8 Ton Tire Load
91
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 20 40 60 80 100 120 140
NomralizedSoilPressure
TirePressure(psi)
6" Normalized Stress
12" Normalized Stress
20" Normalized Stress
Linear (6" Normalized Stress)
Linear (12" Normalized Stress)
Linear (20" Normalized Stress)
92. Timing
• Organic Matter and soil moisture all affect how strong
the soil will be for any given moment.
• Tire pressure or size alone cannot limit compaction.
• Timing plays a major factor in the load placed on the
soil.
92
93. Loads from Forage Equipment
• For a majority of ag equipment, the load on the tires
varies dramatically as equipment is loaded and
unloaded.
• Forage equipment is an exception to this rule.
• the load may not vary at all as it travels across and field.
• Balers,choppers and haybines havea fixed wheel weight that does not change.
• This makes tire selection much more important.
Selecting an appropriate tire will help reduce the load
on the soil.
93
94. Options for avoiding Compaction and the
challenges
• Some options for limiting compaction can cost money
up front
• Newer Tires (IF,VF etc.)
• CTIS
• Additional Axles
• Others can cost no money at all
• Timing
• Controlled Traffic
• Reducing Axle Load
94
95. Tire Types and
Construction
Radial – Separate tread
and sidewall allows tread
face to remain flat as the
tire flexes
Bias – Integral sidewall
alters tread face when
tire flexes
95 Ag Tires - Practical Applications
From Michelin TIRE TECHNICAL DATA BOOK 2017
98. Sidewall Information
710/70 R42 173D TL MACHXBIB
98 Ag Tires - Practical Applications
710- Tread Width in millimeters
70 – Aspect Ratio ( % of sidewall height to Tread Width)
R – Radial
42 – Rim diameter in inches
173– Load Index Rating (indication of maximum load)
D – Speed Rating (maximum travel speed)
TL – Tubeless
MACHXBIB – Manufacturermodel name
101. Table Information
Some manufacturerstableswill include more information
Rolling Circumference– useful for calibratinggrounddriven equipment
Flat Plate Area – an indicationof the contactpatch(butnot necessarily floatation)on a
hard surface at a given pressure and load
SRI – Speed Radius Index – Useful for matchingfront and rear tires on power units
101 Ag Tires - Practical Applications