Soil Compaction
Jan van den Akker
Catalin Simota
Tom Hoogland
Introduction
• Introduction
• Risk Assessment Methods
• Empirical RAM used for The Netherlands
• Deterministic RAM used for The Netherlands
• Dutch Soil Database: prediction subsoil compaction
• Conclusions
Definition of subsoil
TOPSOIL
PLOUGH PAN
SUBSOIL
Subsoil compaction is (partly) irreversible
Effect
Resilience
-
---
+
0/-
--
-
0/-
-
--
Risk
topsoil
ploughpan
subsoil
Human activities
Mechanical stress on soil surface (wheels,
tracks or rollers of agricultural and construction
machinery)
Air filled soil pore volume reduction
Reduction of soil biological activity and soil productivity
Decreased water infiltration capacity and increased erosion risk
Risk Assessment Methods
1 Empirical RAMs: based on measurements, monitoring,
experience, evaluation
Hungary, former DDR, Poland, Slowakia, Romania
2 Deterministic RAMs: based on a soil mechanical approach
Germany, Sweden, Denmark, Romania, Spain, France
(Netherlands)
3 RAM based on mass of agricultural machinery
Italy
Empirical RAM (based on experience, Jones et al., 2003)
This is a two-stage methodology to assess the vulnerability of subsoil
to compaction:
1 Assessing the inherent susceptibility based on texture and packing
density.
2 Combining this soil susceptibility with an index of climatic
dryness/subsoil wetness, to determine the vulnerability class.
Texture classes EU soil map
100
10
VERY FINE
20
30
70
40
60
50
50
FINE
(2
60
40
70
30
MEDIUM
FINE
MEDIUM
20
10
)
µm
50
Pe
rce
nt
CL
AY
(<
2
80
T
SIL
nt
rce
Pe
µm
)
90
80
90
COARSE
0
10
10
20
30
40
50
60
70
80
90
0
10
Percent SAND (50 - 2000 µm)
Packing Density
Determined in a soil pit (visual)
OR
PD = Db + 0.009C …………………………………(1)
Where Db is the bulk density in t m-3
PD is the packing density in t m-3
C is the clay content (%, by weight)
low
<1.40,
medium 1.40 to 1.75
high
> 1.75 t m-3.
Inherent susceptibility to compaction according to texture and packing density
Packing density t m
Texture
Code
-3
Low
Medium
High
< 1.40
1.40 – 1.75
> 1.75
Texture Class
1
1
Coarse
VH
H
M
2
Medium
H
M
M
3
Medium fine
M(H)
M
L
4
Fine
M
L
L
5
Very fine
M
L
L
9
Organic
VH
H
Jones et al
(2003)
Susceptability
(texture, packing
density)
Vulnerability to compaction according to soil susceptibility and climate
Class
Climate Zone
Perhumid
Humid
A
SubB
humid
Dry
Subsoil
Usually wet,
Often wet,
Usually
Seasonally
Moisture state
always moist
usually
moist,
moist and dry
Mostly dry
moist, rarely
seasonally
dry
dry
Soil
PSMD mm
≤ 50
51 – 125
126 – 200
201 – 300
> 300
Susceptibility
FC Days
> 250
150 –
100 – 149
< 100
≤ 40
E (E)
V (E)
V (V)
M
250
1
2
VH
E (E)
H
V (E)
V (E)
M (V)
M (M)
N
M
V (E)
M (V)
N (M)
N (N)
N
L
M (V)
N (M)
N (N)
N (N)
N
Jones et al
Vulnerability
(susceptibility,
climate)
Deterministic RAM (based on soil mechanical approach)
Determination precompression strength with uniaxial test
Pv
Precompression stress (pF 1.8), 30-60 cm soil depth for Germany (SIDASS-model)
Precompression stress classes:
1 Very Low
< 30 kPa
2 Low
30 - 60
3 Mean
60 - 90
4 High
90 - 120
5 Very High
120 - 150
Compaction by compression and shear
Terra Tyre, sandy soil, wheel load 80 kN (8 tonnes)
Soil failure
2.5
17.5
32.5
62.5
Compaction by:
■ shear + compression
■ shear
■ compression
77.5
92.5
107.5
122.5
Distance (perpendicular to dirving direction) to centre (cm)
-145
-130
-115
-100
-85
-70
-55
-40
-25
-10
5
20
35
50
65
80
95
110
125
140
137.5
Depth (cm)
47.5
Wheel load carrying capacity
Wheel load carrying capacity is reached if:
Exerted stresses (load, tyre width, inflation pressure)
=
Strength subsoil
Max wheel load (kN)
- Terra Tyre
- Subsoil
Empirical Ù Deterministic
Empirical RAM
Deterministic RAM
Texture, BD
Soil mechanical
properties
Climate zones,
percipitation,
evapotranspiration
Wet or moist soil
Land use
-
Land use => wheel
loads
Management
-
Wheel loads
Experience
-
Soil Properties
Climate
Resilience
Dutch Soil
Database:
BD upper subsoil
Dutch Soil
Database:
Frequency
BD upper subsoil
Dutch Soil Database:
Predicted subsoil
overcompaction in
2010
Conclusions
•
•
•
•
•
•
•
•
All RAMs are not complete
Empirical RAMs are limited to experiences in countries
Empirical RAMs neglect wheel loads
Deterministic RAMs are more universal and “scientific”
Deterministic RAMs neglect impact on soil properties
Deterministic RAMs neglect resilience
Deterministic RAMs require soil mechanical properties
Results RAMs are not always in agreement
•
•
Subsoil compaction increases in the Netherlands
Not in agreement with RAMs?
•
Further development of deterministic RAMs is the best option for
harmonization
5
pF (log(-soil water suction))
4
3
2
1
0
32
36
40
44
Pore volume (%)
PR too high
Rootable
Too w et, aeration too low
Aeration limiting
PR limiting
Too dry
Bad structured soil
Bad structured soil
48
Reduced infiltration capacity
ENVASSO
INDICATORS
KEY ISSUES
Density
(bulk or packing density, total porosity)
Air Capacity
Compaction and
structural degradation
(air-filled pore volume at specific suction)
Permeability
(saturated hydraulic conductivity)
Visual assessment of structure and testing
Mechanical resistance
(penetrometer resistance)
Vulnerability to Compaction (estimated
Vulnerability to
Compaction
Causes of Compaction
from texture, density, climate, land use)
Drainage condition (wetness class)
Soil strength (precompression strength)
Ground pressure
Soil management and tillage practice
Soil Properties
Soil functions and sub-functions that are directly affected by soil
compaction, and soil parameters as possible indicators (Lebert et al.,
2003).
Soil function
Soil sub-function
Indicator
Single Parameter
Indicator:
Aggregated Parameter
Air regime
- Air storage
- Air flow
Air capacity
Bulk density
Air permeability
O2-Diffusion
For all sub functions:
Water regime
- Water storage
- Water flow
Water storage
Available water capacity
Bulk density
Water conductivity
(saturated/unsaturated
Plant production
- Rootability
Root length density
Bulk density
Penetration resistance
Visual classification of soil
morphology by:
- Effective bulk density
- Packing density
- Spade diagnosis
Soil Physical Threshold Values (1)
Packings density PD
PD = Db + 0.009C (g cm-3)
Db = dry bulkdensity (g cm-3)
C = clay content (weight %)
Low
Medium
High
PD < 1,40
PD 1,40 - 1,75
PD > 1,75
Dry bulkdensity Db
Db < 1.75 - 0.009C (g cm-3)
Db < 1.6 (g cm-3 )
Soil Physical Threshold Values (2)
Pore volume n
n > 40%
Air filled pores ng
Bakker et al., (1987)
Diffusion coëfficiënt Ds
Never problems if Ds > 30 10-8 m2 s-1
Allways problems if Ds < 1.5 10-8 m2 s-1
Soil structure
Very good
Good
Medium
No, bad
Air filled pores ng :
At least
Desired
>2%
> 14 %
>5%
> 15 %
>8%
> 17 %
> 12 %
> 21 %
Soil Physical Threshold Values (3)
Hydraulic saturated conductivity Ksat
Ksat > 10 (cm day-1)
Assessment: Packing density and bulk density ploughpan
Dry bulk density (g/cm3)
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0
20
40
60
Clay content (%)
80
100
Precompression stress, kPa
Climate
(Arvidson et al)
300
0.30 m
250
200
150
100
y = 40.655Ln(x) - 10.568
2
R = 0.9288
50
0
0
50
100
Tension (kPa)
150
200
Land use
•
•
•
Grassland
Arable farming,
- Ploughing
- No-Till
- Biological farming
- Conservation Tillage
Forest
•
•
•
Grains
Root crops
Silage maize
•
Heavy mechanization
Management
Sugarbeet harvesters 1999: Weight and wheel loads
Machine
Gross vehicle weight (kN)
Vehicle weight, empty (kN)
Payload full tanker (kN)
Wheel load full, left front (kN)
Wheel load full, right front (kN)
Wheel load full, left middle (kN)
Wheel load full, right middle (kN)
Wheel load full, left rear (kN)
Wheel load full, right rear (kN)
Vervaet 17
382
226
156
114
114
77
77
Holmer
Riecam Ropa Euro
Terra Dos RBM 300-S
Tiger
461
401
589
274
246
314
188
155
275
104
109
101
99
124
94
109
117
129
76
84
130
93
84
WKM
Big Six
447
262
185
83
64
76
65
92
68
Kleine
SF 40
518
285
233
75
73
93
79
92
107
Sugarbeet harvesters: Wheel loads and inflation pressures
Machine
FRONT TIRES
Holmer
Michelin
Agrifac
Vervaet
Michelin Trelleborg
make
size 800/65R32 800/65R32
width (mm)
Wheel load full, left front (kN)
Wheel load full, right front (kN)
measured infl. press., left (kPa)
recommended infl. press., left (kPa)
measured infl. press., right (kPa)
recommended infl. press., right (kPa)
798
82
97
180
165
180
225
The recommended inflation pressure is for field use
798
95
90
180
220
170
200
850/60-38
850
120
106
210
280
190
225
WKM
Michelin
Vredo
Michelin
Riecam
Tim
Michelin GoodYear
11.2R36 750/65R26 800/65R32 800/65R32
284
26
26
260
400
250
400
754
76
74
190
205
190
200
798
120
96
190
300
200
225
819
99
90
180
235
170
200
Resilience: Persistence of subsoil compaction
(Alakukku et al)
L
L
120
L
L
L
4
5
S
L
Mean yield (%)
110
100
90
80
70
1
2
3
6
7
8
9
10 11 12 13 14 15 16 17
Years after compaction with wheel load of 50 kN
Grain yield
Nitrogen yield
L = lodging S = sprouting Control =100 %
x
Database
criteria
CRITERIA
Country
Your Name
Quest number
RAM available?
Soil typological unit
Land use
Equipment use
Germany
Lebert
4B
Y, I
(STU)
X
e.g. LUCas
X
Weight, Wheel Load, Inflation Pressure , Tyre type W, WL, IP, W, WL, IP,
Ty
Ty
Yes, Official, Development, Institute
e.g. Corine
Land cover
Digital elevation model
Topography
Pedotransfer functions
PTF +
Texture
OM
Density
Moisture
Drainage class
Air
Germany
Paul
Land Cover, Land Use, Spatial Soil Info
4A
Y, I
X
Field Capacity, Wilting Point, Water content sat,
Workability Limit, Infiltration cap. sat
4C
Y, I
4D
Y, I
Poland
Lopiec
5A
Y, I
IP
X
X
GIS
X
Bulkdensity dry, Bulkdensity at fc, Packing
Density, Porosity, Degree of Compaction
Germany Germany
Haider
Marahrens
Bd, PD
Model +
GIS
X
X
Bd, PD
X
X
GIS
LC
X
X
Bd, PD
X
X
Bd, Bfc,
Bd,
PD
DegComp
FC, WP,
FC, WP,
Wsat, Ksat Wsat, Ksat
FC, WP,
Ksat
FC, WP,
Ksat,
Infil_sat
FC
Acap
Acap, Diff
Acap
Acap,
Acond
Acap,
Acond, Diff
PreC,
ShearS
PreC
PreC,
ShearS
PreC
Pen
Ps, PEs
Py, Ps, Tj,
Ts
Poland
Denmark
Greece
Stuczyński Schjønning Papadopo
ulos
5B
6A
12A
Y, I
Y, I
No
X
X
X
X
X
W, WL, IP,
W
Ty
X
X
X
Model +
GIS
X
X
Model +
GIS
X
X
FC, WP,
Wsat,
WorkL,
Ksat
FC,
pFcurve
Italy
Bazzoffi
Finland
Alakukku
Hungary
Birkás
Belgium
Bielders
Belgium
18A
Y, O
20A
No
24A
Y, I
X
X
25A
No
X
X
25B
Y, D
X
X
X
X
X
W, WL, IP
X
LC, LU
X
X
Bd, Bfc,
Por
FC, WP,
Wsat
GIS + SSI
X
X
X
X
Bd, Bfc
Ksat
FC,
WorkL,
Ksat
X
Air capacity, Air conductivity, Diffusion
Mechanical
PreCompression stress, Shear Strength,
Penetration resistance
Climate
Precipitation, Temperature, Radiation, Potential
Evapotranspiration, yearly, seasonal, monthly, 10
days, daily
Climate +
Land Cover, Land Use
Ps
LC
Acap
X
X
X
X
X
Acond, Diff
Pen, PreC Pen, PreC
Rd, Ped
GIS +
Model
Pen
Py, Pm,
Tm, Ry,
Rm, PEy,
PEs
LC, LU
Pen
R10, PEs
Py, Ps,
Pm, Pd,
Ty, Ts
Py
Database
THRESHOLDS
Country
Quest number
RAM available?
Water content
Saturated hydraulic conductivity
Air capacity
Oxygen diffusion rate
Thresholds
Germany
4A
Y, I
Germany
4B
Y, I
10 cm/d
5 vol%
10 cm/d
5 vol%
1
Germany
4C
Y, I
Germany
4D
Y, I
10cm/d
5 vol%
Poland
5A
Y, I
FC
Precompression stress
Dry Bulk Density
> Load
> Load
X
Italy
18A
Y, O
Finland
20A
No
Hungary
24A
Y, I
X
2,8-3,0 MPa
> Load
Klassen 4/ 5
(dicht/ sehr
dicht)
Klassen 4/ 5
(dicht/ sehr
dicht)
Belgium
25A
No
Belgium
25B
Y, D
-1
1.4-1.5 Mg
m-3
class 4 and
5 (DIN
19682-10,
Germany)
Greece
12A
No
X
24 cm/d
2-3 Mpa
Bulk Density at Field Capacity
Packing Density
Denmark
6A
Y, I
10 vol %
<30 µg m-2
s
Penetrometer values
Poland
5B
Y, I
X
X
X
1,5 g cm
-3
X
Database
RAM used (1)
RAM used
Country
De
Quest number
4A
Is there a risk assessment methodology in your country at present or in development? Y, I
No
Is the RAM linked to Community policy
X
De
4B
Y, I
X
De
4C
Y, I
X
De
4D
Y, I
X
X
X
Po
5A
Y, I
Po
5B
Y, I
X
targets, objectives or legislation?
Yes, indirectly
Yes, directly
Don’t know
Not at all
Could the RAM provide information that is
useful to policy action/decision?
Fairly useful
Very useful
Don’t know
How would you describe the sensitivity of the Not sensitive: delayed response
RAM?
Intermediate response
Fast, immediate response
Don’t know
What type of methodology is this RAM?
expert-based
Qualitative:
(multiple answers possible)
weighting-rating
Quantitative: empirical model
process based-model
Expert analysis
Historical documents
Other: (please specify )
Is the RAM based on indirect (e.g.
Indirect
questionnaires to farmers) or modelled or
Modelled
direct measurements of a state/trend?
Direct
Don’t know
Dk Gr
It
Fi
Hu Be Be
6A 12A 18A 20A 24A 25A 25B
Y, I No Y, O No Y, I No Y, D
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Database
RAM used (2)
Country
De
Quest number
4A
Y,
I
Is there a risk assessment methodology in your country at present or in development?
Is the RAM based on low/medium/high low
medium
quality statistics or data?
high
X
Yes
X
Is the RAM used for monitoring
No
purposes?
Don’t know
only case studies
Is there good geographical coverage?
national
national and regional
Don’t know
What types of techniques are being used in Field observation
such methodology?
Remote sensing
Geographical information systems
Laboratory analysis
Other:
What is the availability of time series for
None
implementation of the RAM?
Occasional data source
Regular data source
Don’t know
At what time are time interval data collected? Annually
Once every 1- 5 years
Once every 5-10 years
Other (please specify)
Don’t know
Are outputs of the RAM clear and easy to
Not at all
understand?
Fairly clear
Very clear
De
4B
Y, I
De
4C
Y, I
De
4D
Y, I
Po
5A
Y, I
Po
5B
Y, I
X
X
X
X
X
X
X
X
Dk Gr
It
Fi
Hu Be Be
6A 12A 18A 20A 24A 25A 25B
Y, I No Y, O No Y, I No Y, D
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Database
RAM used (3)
Country
De
Quest number
4A
Is there a risk assessment methodology in your country at present or in development? Y, I
Database is accessible to:
the general public
administration
scientific purposes
Other:
Output documents are composed of (multiple Geomorphologic map
answers possible):
Hazard zone map
Geotechnical map
Vulnerability zone map
Elements at risk
Risk zone map
Other susceptibility map
What is the scale of the cartographic output 1:5000
documents (several answers possible
1:10000
1:20000
1:25000
Other: (please specify)
Based on existing statistics and data sets?
No
Yes
Are the statistics or data needed for
No
compilation easily accessible?
Yes, but requires lengthy processing
Is the setup of a (new) monitoring network
Yes
required?
No
Yes, additional measurements to an existing mon
Yes
Don’t know
De
4B
Y, I
X
X
De
4C
Y, I
De
4D
Y, I
X
X
X
Po
5A
Y, I
Po
5B
Y, I
X
X
Dk Gr
It
Fi
Hu Be Be
6A 12A 18A 20A 24A 25A 25B
Y, I No Y, O No Y, I No Y, D
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Soil Directive
Eckelmann et al, 2006. ESB report 20
Eckelmann et al, 2006. ESB report 20
Precompression stress
1
0.9
Void ratio
0.8
0.7
0.6
0.5
0.4
0.3
1
10
100
Normal stress (kPa)
1000
Wheel load: Stress propagation in soil
RAM Romania according Jones et al (2003) arable land
RAM according soil mechanical approach (SIDASS) arable land
RAMs compared (arable land)
Climate
(Arvidson et al)
0.30 m
Calculated risk, %
100
80
60
40
20
0
1 May
1 Jul
1 Sep
1 Nov
• Soil Properties
• Climate
• Landuse
• Management
• Resilience