HOW DO WE DIAGNOSE AND MANAGE SOIL COMPACTION

1
HOW DO WE DIAGNOSE AND MANAGE SOIL COMPACTION

• DICK WOLKOWSKI
• EXTENSION SOIL SCIENTIST
• UNIVERSITY OF WISCONSIN

2
SOIL COMPACTION DEFINED

• Compression of the soil from an applied force
  that first re-arranges and then destroys
  aggregates increasing bulk density and reducing
  porosity
• Wheel traffic from field operations
• Tillage
• Livestock

3
Load
Moisture
Tillage History
Strength
Structure
Texture
Soil compacts when load-bearing strength of soil
is less than load being applied.
4
COMPACTABILITY INFLUENCED BY WATER CONTENT

• VARIES BY SOIL
• MAXIMUM NEAR
• FIELD CAPACITY
• DRY SOIL HAS
• MORE STRENGTH
• SATURATED SOIL
• NOT COMPACTABLE

5
B.D. 1.0
B.D. 1.3
B.D. 1.6
COMPACTION IS A PROCESS
6
WHY IS COMPACTION AN ISSUE

• ? Larger equipment ? Time management
• ? Earlier field operations ? Uncontrolled
  traffic
• ? Loss of forage in rotation ? Brain cramps
• ? Operations on wet soils

7
TOTAL AXLE LOAD
VOORHEES, 2002
8
Will more tires spread weight or allow
operations in wetter conditions and compact a
greater soil volume ?
9
LARGER TIRES DONT COMPENSATE FOR LARGER LOADS
10
TRACKS vs TIRES
Compare total load per axle
11
(No Transcript)
12
There really are days you shouldnt be in the
field !
13
Chasing the combine is an old habit
14
CONTROL COMPACTION BY UNLOADING IN HEADLANDS
15

• Soil Response is Variable
• 700 Series
• Texture and
• Structure
• Organic Matter
• and Drainage
• Genetic pans
• Unusual
• Compaction
• Potential Differs
  
  

16
COMMOM SYMPTOMS OF SOIL COMPACTION

• SOIL
• Standing Water
• Excessive Runoff
• Structural Degradation (Clods)
• Difficult to Work
• PLANTS
• Stunting/Uneven Growth
• Nutrient Deficiency Symptoms
• Malformed Roots
• Reduced Yield

17
Pea harvest Vegetable crop contracts often lead
to soil abuse
18
Cloddy soil following corn silage harvest
19
Cloddiness re-defined
20
Stunted, uneven stand is often the first symptom
21
The shovel is an excellent diagnostic tool
22
GROWERS ARE INTERESTED IN COMPACTION MANAGEMENT
Northeast Wis. field day
23
Excavated plow layer
24
Pancake root mass
25
QUANTIFYING COMPACTION

• Crop and Soil Symptoms
• Penetration Resistance
• Moisture Dependent
• No Absolute Value
• Note Depth and Relative Force
• Compare Good and Bad Areas
• Bulk Density
• Mass per Volume
• Calculate Porosity
• Texture Dependent

26
MEASURING PENETRATION RESISTANCE
Hand-held penetrometer
Soil probe
27
CONSTANT-RATE RECORDING PENETROMETER
28
SOIL WATER CONTENT WILL AFFECT PENETRATION
RESISTANCE. ARLINGTON, WIS. PLANO SILT LOAM SOIL
Depth, mm
7/20/2000 Avg. water content 0.27 m3 m-3
6/22/2000 Avg. water content 0.36 m3 m-3
29
EFFECT OF COMPACTION ON SOIL BULK DENSITY OF A
SILT LOAM SOIL

• DEPTH COMPACTION 1991 1992 1993
• in
  --------- g/cc ---------
• 0-6 NONE 1.19 1.30 1.32
  14 t 1.36 1.41
  1.40
• 6-12 NONE 1.31 1.33 1.31
  14 t 1.59 1.50
  1.52
• 12-18 NONE 1.19 1.35 1.33
  14 t 1.45 1.44 1.33
• 18-24 NONE 1.36 1.35 1.34
  14 t 1.40 1.34 1.33

Compacted April 1991 and seeded to alfalfa
30
COMPACTION AFFECTSNUTRIENT UPTAKE

• Potassium Affected Most
• Compaction reduces porosity
• Lowers soil oxygen
• O2 needed for root respiration and active
  uptake

31
COMPACTION EFFECT ON CORN YIELD ON A SILTY CLAY
LOAM SOIL
Oshkosh, Wis.
32
RESPONSE OF CORN TO ROW-APPLIED K ON A SILTY CLAY
LOAM SOIL (3 yr. avg.)
SOIL TEST K
Oshkosh, Wis. (45 lb K20/a)
33
IS COMPACTION A PROBLEM IN FORAGE PRODUCTION

• Compaction Limits Growth and Yield
• Potential High in Forage Production
• Fertilizer and Lime Applications
• Liquid Manure
• Normal Management Many Traffic Passes
• Harvest on Wet Soils
• K/Compaction Relationship
• Alfalfa Has a High K Need

34
Alfalfa winter-kill resulting from wheel traffic
35
EFFECT OF COMPACTION ON ALFALFA YIELD ON A
SILT LOAM SOIL
Arlington, Wis.
36
K SOIL TEST AND ALFALFA YIELD ON A COMPACTED SOIL
(sum of 3 yrs.)
SOIL TEST K
Arlington, Wis.
37
DETERMINING THE NEED FOR SUBSOILING

• Evaluate depth and severity of compaction
• Check with penetrometer, probe, shovel
• Dig plants to examine roots
• Leave untreated strips for comparison
• Subsoiling is not a cure-all

38
CONVENTIONAL TILLAGE CAN REMOVE LIGHT
COMPACTION
PENETROMETER RESISTANCE FOLLOWING TILLAGE OF A
LIGHTLY COMPACTED SILT LOAM SOIL
Arlington, Wis., 2002 (6 t vehicle)
39
OTHER SUBSOILING CONSIDERATIONS

• Burial of crop residue
• Destruction of natural channels
• Sidewall smearing
• May bring stones, clay, infertile soil to the
  surface
• Does not address compaction cause

40
SOIL BULK DENSITY PROFILE, ARLINGTON, WIS., 1998
Depth (in)
R
R
0 8 16
R
R
0 8 16
PLANO SILT LOAM
41
EFFECT OF TILLAGE AND K FERTILIZATION ON
FIRST-YEAR CORN YIELD AFTER SOYBEAN (2 yr. avg.)
Arlington, Wis.
42
WHICH TYPE OF SUBSOILER
Conservation - Cutting coulters - Straight
shanks - Horizontal points
V-Ripper - Leading disks - Parabolic shanks -
Winged points
43
EFFECT OF SUBSOILER TYPE ON SOYBEAN AND CORN
YIELD ON A SILTY CLAY LOAM SOIL
Soybean
Corn
Manitowoc, Wis.
44
GUIDELINES FOR MANAGING SOIL COMPACTION

• Minimize Load Weight, Operations on Wet Soils,
  Control Traffic
• Evaluate and Monitor Crops and Soil
• Use Common Sense
• Subsoil Only if Documented Compaction Conditions
  Exist
• Address Compaction Issues