Repairing ravaged soils - Dr. Sjoerd Duiker, Extension Agronomist, Penn State University, from the 2020 Conservation Tillage and Technology Conference, held March 3-4, 2020, Ada, OH, USA.

1. Photo from Randall
Reeder
RECOVERING FROM 2019
GETTING YOUR SOIL BACK IN SHAPE
By Sjoerd W. Duiker
Soil Management Specialist

2. 20 million acres of prevented planting in 2019, record was 10 million acres
(2011)
1. South Dakota – 3.9 million Corn 11.4 million
2. Ohio – 1.6 million Soybeans 4.5 million
3. Illinois – 1.5 million

3. Photo by Paul Jasa
Tillage to “dry out soil”
Perhaps you are faced with the
aftermath of this…..

4. Or this…..

5. Corn in foreground followed soybeans, corn in background followed no crop
(Gregory Luce, University of Missouri)
https://ipm.missouri.edu/IPCM/2016/6/Stunted_Corn_Following_Prevented_Planting-Fallow_Syndrome/
Potential problems after prevent planting

6. https://ipm.missouri.edu/IPCM/2016/6/Stunted_Corn_Following_Prevented_Planting-Fallow_Syndrome/
Fallow syndrome can affect mycorrhizal colonization and P-uptake in corn
P-Deficiency Potential problems after prevent planting

7. 4 million acres (20%) of 20 million prevented plant acres were planted to cover crop

8. Brassica (cover) crops - no mycorrhizae
Mycorrhizal colonization, N and P shoot
concentration, and shoot dry weight of maize in four
rotations.
Koide and Kabir, 2012. Plant Soil 360:259-269

9. 0
5
10
15
20
25
30
35
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Trafficabledays(#/month)
Well-structured pasture without
plow-pan
Arable land with plowpan
Improve Trafficability
with Continuous No-Till Systems
Long-term undisturbed soil with active root system has good trafficability

10. Long-Term No-Till increases Macro- Porosity
Which Helps to Improve Soil Drainage
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Pasture (emulated by no-till)
Plow pan
Subsoiled, then
Recompacted
Small Medium Large
Percent > 0.0012”
Percent pore size at depth of plow pan in study in the Netherlands
Macro-pores are important for water transmission and aeration

11. 0
5
10
15
20
25
30
35
40
45
No-till Mulch till Reduced till Conventional till
% prevented planting less in no-till
South Dakota, 2019
USDA Data, reported in No-Till Farmer - Conservation Tillage
Guide, February 2020

12. Compaction
Compaction
Compaction

13. 1.35
1.4
1.45
1.5
1.55
1.6
1.65
w/o Rye with Rye
Early
Late
a a a
b
0-4” depth
Rye effect on bulk density (g/cm3
)
in following corn crop in July
Early = early killed cover crop
Late = late killed cover crop With Rye w/o Rye
Both samples under manure spreader tracks on dairy farm operation
Improve soil structure with vigorous cover crops

14. • Cover crop roots
provide‘geotextile’
below soil surface
Annual Ryegrass Cover Crop
Hairy Vetch Cover Crop
Improve soil with Cover Crops

15. Cover Crops to Improve Soil Structure
Rorick, J.D., and E.J. Kladivko. 2017. Cereal rye cover crop effects on soil carbon and physical properties in southeastern Indiana. J.Soil & Water Cons. 72:260-265
Effects of cereal rye cover crops on mean weight diameter (MWD) of
aggregates after 4 years in corn-soybean rotation. Southeast Indiana.

16. 15
20
25
30
35
40
5/19/2016 5/26/2016 6/9/2016 6/15/2016 6/30/2016 7/7/2016 8/4/2016
%Moisture
Rock Springs 2016 Rye termination timing
effect on volumetric soil moisture (0-3in.)
Early
Late
*
*
*
* *
PG
*Indicates p<0.05
Use Planting Green to Dry Soil in Spring

17. Use Cover Crops to Repair Compaction
Chen, G., and R.R. Weil. 2010. Penetration of cover crop roots through compacted soil. Plant Soil 331:31-43.
Beltsville, MD. Coastal Plains loamy soil
High compaction = Two passes with 13 Ton resp. 14.2 T axle load, high contact pressure (ca 100 psi)
Medium compaction = One pass with 13 T axle load and 100 psi contact pressure.
No compaction = No compaction
Soil was subsoiled to 18”, then moldboard plowed, then disked prior to trial.
Compaction was applied once, then field was disked to 3 inches depth
Cover crops were planted in mid-late August 13 lbs/A radish, 8 lbs/A rape, 2 bu/A rye. 20-25 lbs N/A applied
Corn was planted and harvested for silage in second year, and cover crops planted again.
Cores were taken to 17 inch depth in late Nov/early Dec of each year, and roots counted by breaking cores every 2 inches

18. Cover crop roots to re compaction
1st year
2nd year
High Compaction Medium Compaction No Compaction
Tap-rooted species seem to be more effective
to alleviate compaction
* less friction with soil
* Less ‘buckling’

19. Canola roots
penetrate
plow pan in
winter when
soil is soft
Soybean roots
follow root
channels
created by
canola
Williams and Weil, 2004
Remediate Compaction with Tap-Rooted Cover Crops
that grow in Fall/Winter

20. Improve Soil by Stimulating Biological Activity
Worm holes covered with organic matterFeed the soil and it will feed you!

21. Nightcrawler burrow
Fresh Cast
Removed
midden
Improve Soil by Stimulating Earthworm Activity

22. What about tillage to
alleviate compaction
• Shallower loosening operations to 12”-14”
depth have sometimes shown benefit
• Deeper subsoiling may be disappointing:
– No yield improvement in 3-yr subsoiling study
on 16 sites in UK except on compacted sandy
soils with spring planting (Sloane et al., 1987)
– North American review of subsoiling also
failed to show yield improvement in many
cases (Burnett & Hauser, 1967)
• Subsoiling may have positive effect where
drought stress is severe
• Clayey soils can ‘repair themselves’ due to
swelling and shrinking
From Spoor, 2006

23. Remember Negatives of Tillage
• Tillage buries residue, increasing
erosion
• Goal should be to leave AT LEAST
30% crop residue after planting
• Tillage ‘burns up’ organic matter
• Tillage destroys soil structure
• Tillage harms biological activity
• Tilled soils more compactible,
greater rutting

24. Negatives of Tillage in Continuous No-Till or Grassland Soils
• Risk of clod problems
• Loss of soil support
• Risk of pugging
• Risk of re-compaction
• Damage to natural root and
earthworm channels
• Kill of cover crop or sod

25. But what to do if I have a severely compacted /
rutted field?
– Need to level field for good per-
formance of planter/drill/
harvesting equipment
– Need to reopen macro-pores
– Need to cause minimal loosening
and aggregate rearrangement
– Need to create fissures in
compacted soil in bottom of ruts
– Try to limit tillage depth, inversion,
and residue cover reduction

26. Diagnose problem
and chart a way forward
– Is rutting limited to a few areas of
the field (e.g. less than 10-20%?) –
localized remediation may be
enough
– How deep are ruts – if only 1” deep
no further action may be needed
– Is field leveling sufficient? – then
field cultivator or shallow disking
might suffice
– Is deep tillage needed to bust up soil
in rut bottoms? – deep tillage may
be needed followed by leveling
operation

27. Subsoiling vs Zone-Till
Penetration resistance (psi)
0 50 100 150 200 250 300 350
Depth(")
0
5
10
15
20
No compaction
Compacted
Compacted, then subsoiled
Compacted, then zone-tilled (subsoiled in 2002)
Measurements performed with a recording penetrometer in May of 2003, with soil approximately at field capacity.
No-till experiment, airport, State College, PA.
Compaction, no-till
Compacted,
then subsoiled
No
compaction
Compacted, zone-tilled this
year, subsoiled year before
How deep
do I need
to till?
Penn State Compaction Trial
Depth of compaction

28. Tillage without
inversion please!
No coulters to work in residue
Parabolic shanks
High surface disturbance
Coulters to work in residue
Straight-legged shanks
Low surface disturbance

29. Modern
Subsoilers
minimum
residue disturbance
Aim Philosophy Effects
School 1 Max fracturing
(e.g. DMI,
paratill)
Max fracturing between
shanks stimulates root
growth, infiltration, aeration
Effects of fracturing great
immediately after, threat
of re-compaction
School 2 Min fracturing
(e.g. Unferverth
Roots, water, air will follow
channels created by shanks
Effects of fracturing
smaller, re-compaction
threat smaller
School 1 School 2

31. Front coulter, straight shank subsoiler with coulters and rolling basket

33. Straight shank subsoiler with press wheels

34. Field cultivators to level field
Field cultivator, with small sweeps
mounted on front and spring-tine
harrow on back.
Field cultivators can work in fields
having large amounts of surface crop
residue. Their length and height allow
for clearance between shanks and flow
of residue through the machine.

35. Field cultivator sweeps are widely spaced to handle heavy residue

36. Spring-tine harrow can work in heavy residue

37. Field Cultivator Sweeps Tine-
harrow
Rolling
basket

38. Rolling basket

39. After repair with tillage …..
C. Mulch cover should be preserved
S. Soil structure needs to be rebuilt
using close-spaced crops (cover crops,
small grains, hay…)
T. Traffic needs to be managed or we
go into a vicious spiral of tillage.
B. Need to restore soil structure
encouraging soil biology – using no-
till, cover crops, deep rooted crops,
organic matter additions

40. In Summary: Remedial strategies for this year
• Fix your fields with appropriate tillage only if needed
• Good time to consider transitioning to a no-till system
• Make sure P levels are not low – using manure?
• Plant soybeans – less affected by fallow syndrome
• Try to use shorter day corn or soybean varieties
• Try growing small grains in rotation
• Plan to use cover crops
• Plant brassicas only in cover crop mixes