Iowa Cover Crops Conference February 17-18, 2015 West Des Moines, IA

1. Cover Crop Innovations
Tracy Blackmer
Feb. 18, 2014
Cover Crop Solutions
tblackmer@covercropsolutions.com

2. Tile drainage
• Nitrate moves freely with water
• Most of nitrate loading from tile
lines
• Tile lines usually run before and
after corn and soybeans are
taking up N
Nitrogen Loss
Notice the lack of green on the land and the
water flowing from tile line

3. Water Quality
July 29, 2014
Big Creek Reservoir
Iowa, USA
No Swimming permitted
Drinking water source

4. Most common reason for
cover crops
• Erosion control often a “gateway”
usage of cover crops.
• Requirements for erosion control
are not necessary the same as
other usages.
• Specifics must be adapted to local
issues
Benefits of Cover Crops

5. Cover Crop Seed
More than cereal rye Hairy
Vetch
Tillage
Radish®
Crimson
Clover
Annual
Ryegrass
Winter
Peas
Oats Cereal
Rye
Triticale

6. Cover Crop Roots

7. Planted cover crops
• In trash cans
• Triticale, Radish, Clover, and Annual
Ryegrass
• Soil mix to easily separate roots
Root Can Study

8. Roots are often under
estimated
Key Point
34 days of growth

9. Crimson clover
Key Point
34 days of growth

10. Nutrient Scavenging
Increased N Scavenging
• Fall planted cover crop
• Captures N at lower depth
• This N could be lost by next
spring
Nitrogen Capture
Ray Weil, University of Maryland
0
5
10
15
20
25
30
35
40
45
50
55
60
0 10 20 30 40 50 60 70 80 90 100
Soildepth(inches)
Nitrate N in each 6 inch soil layer (lb/a)
Tillage Radish
No Cover Crop

11. Plant uptake
• Holds leachable
nutrients
• Relocates nutrients
• Increases available
forms of nutrients
Nutrient Uptake

12. Nitrogen Application
• Angle with NH3
• Plant differences
Early Season Nutrient Stress
June 3, 2014

13. Iowa Prevented Planting
Case Study
• There was a pre-plant application
of 60 lbs N/a. No additional N
was added.
• Around the 1st of Aug. the field
was disked, the Tillage Radish®
seed was broadcast and a roller
was used to get a firm seed
contact.
• A good stand was established.
Case Study – Nutrient Catch Crop
Cambridge Iowa, 2013

14. Nutrient Analysis
• An average of 364 lbs of N were
taken up by the Tillage Radish®
• Plus other nutrients
Case Study – Nutrient Catch Crop

15. Case Study – Nutrient Catch Crop
Nitrogen Needs
• Only 50 lbs N/a was needed
to optimize grain yield for
230+ bu/a corn.
• Despite over 350 lbs N in the
TR catch crop, N was still
needed, but at a much lower
than anticipated amount.
• The lack of full N credit is
speculated to be a loss from
rain rather than a lack of N
release.

16. Cover crop roots can
“loosen” the soil
• Roots can go deeper than most
tillage operations
• Can keep aggregate stability.
Soil Conditioning
0
5
10
15
20
25
0 100 200 300 400
SoilDepth(inches)
Penetration Resistance (lbs/in2)
Soil penetrometer resistance with and
without cover crop
Tillage Radish
No Cover Crop

17. Increasing Root Growth
Increased Rooting Depth
• Fall planted cover crop
• Following season’s corn roots
• More corn root growth at
lower depth
Increased Corn Rooting
Weil and Chen. 2007
0
5
10
15
20
25
0 2000 4000 6000 8000
SoilDepth(inch)
Corn Root Growth (roots/sq yard)
Tillage Radish
Cereal Rye
No Cover Crop

18. Increasing nutrient
availability
• Cover crops increased nutrient
availability in the top 10 inches
Increasing Nutrient Availability

19. University of Maryland with
the Tillage Radish®
• 70 comparisons over 5 years
• 12 bu/a corn yield increase
• 8 bu/a soybean yield increase
• No yield decreases
Yield Trials

20. Nematode control
strategies
• Non-Host crops
• Biofumigants
• Hatch and Starve
• Increasing the Suppression
Nematodes
Isothiocyantes
+ Myrosinase
In Brassica tissue
Volatile “bio-fumigant”
Glucosinolates
Rupturing Cells
Some
control
Limited
impact
Odor

21. Nematode Reduction
• Field studies in IL have shown a
meaningful reduction.
• Data from each site was
replicated three times over 2
years.
• Mechanism not understood,
but looks promising.
• More research needed.
Soybean Cyst Nematodes
Site No Cover Cereal Annual
Crop Rye Ryegrass
----------------SCN Eggs-----------------
1 7533 717* 117**
2 3650 320* 0**
3 1559 722* 386*
4 1202 390* 279*
*significant 0.05
**significant 0.01
Mike Plumer, Univ. IL

22. Nematode Reduction
• Field studies in IL have shown a
meaningful reduction.
• Data from each site was
replicated three times over 2
years.
• Mechanism not understood,
but looks promising.
• More research needed.
Soybean Cyst Nematodes
Site No Cover Cereal Annual
Crop Rye Ryegrass
----------------bu/a----------------
1 48.9 53.8 55.7
2 48.2 52.3 60.6
Mike Plumer, Univ. IL
Soybean grain yield following cover crops

23. Inter-seeding?
• Can you plant a cover crop earlier
in the season?
• Need light to get established
• Will it hurt yield?
Establishing a Cover Crop
Penn State University

24. Corn Yield as Affected by Interseeding
140
150
160
170
180
190
200
Untreated control Annual Ryegrass Legume mix Grass-legume mix
CornYield(bu/a)
Effect of Interseeded cover crops
Penn State, 2013

25. Establishing a Cover Crop
Most common cover crops used for interseeding
RootMax Annual Ryegrass Tillage RadishCrimson Clover

26. Thank you.
CoverCropSolutions.com
TillageRadish.com
800-767-9441
Cover Crop Solutions
Tillage Radish
@CoverCropTweets
@TillageRadish