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

1. Matt Ruark
University of Wisconsin-Madison
University of Wisconsin-Extension
COVER CROPS &
NUTRIENT CYCLING
2015 Iowa Cover Crops Conference
February 17-18, West Des Moines, IA

2. Jim Stute-UWEX
Mike Ballweg-UWEX
Kevin Shelley – NPM
Richard Proost –
NPM
Jaimie West – UW-
Madison
Megan Chawner –
UW Discovery Farms
Wisconsin Fertilizer
Research Council
SARE
UWEX
Wisconsin Farmers
COLLABORATORS & FUNDING

3.  N credits from clovers
 N uptake and N credits from radish
 N uptake from rye and effect on soil nitrate
OUTLINE

4. PLANO SILT LOAM (TYPIC ARGIUDOLL)

5.  Immediate reduction in N loss through uptake
 Providing a nitrogen credit (green manure)
 Increasing subsequent crops yield
Three types of cover crops evaluated:
 Legumes (for the N credit)
 Grasses (for the N uptake)
 Radish (for the N uptake; for an N credit?)
SHORT-TERM BENEFITS OF COVER CROPS

6. RED CLOVER

7. No clover
y = 104.9 + 0.9459x - 0.0026x
2
r2
= 0.9021
N max = 182
Clover
y = 176.8 + 0.5318x - 0.0021x2
r
2
= 0.3083
N max = 127
0
50
100
150
200
250
0 40 80 120 160 200 240
N Rate (lb/a)
Yield(bu/a)
Clover No clover
N Credit, 55 lb/acre
Stute and Shelley, unpublished
Corn response to nitrogen, Janesville 2010

8. Pictures taken October 1, 2013

9. SUMMER SEEDED LEGUMES
Oct. 25, 2013
Ballweg, UWEX
Berseem Crimson
177 lb-N/ac AGB117 lb-N/ac AGB

10. Three locations in
WI
Radish vs. no radish
following winter
wheat
Objective: determine
if there is a nitrogen
credit for radish
RADISH STUDIES

12. N UPTAKE – ROCK CO.
2011 Radish N Uptake, Rock Co.
Radish Radish+60 Winter wheat
Nitrogenuptake(lb/ac)
0
50
100
150
200
250
2012 Radish N Uptake, Rock Co.
Radish Radish+60 Winter wheat
Nitrogenuptake(lb/ac)
0
20
40
60
80
100
180 180
120
70
40
20

13. 2012 SOIL NITRATE (PPNT)
May 2012, Soil Nitrate @ Rock Co.
R
adish
(0-1’)R
adish
(1-2’)
R
adish+60
(0-1’)
R
adish+60
(1-2’)N
o
radish
(0-1’)N
o
radish
(1-2’)
Soilnitrate(ppm)
0
10
20
30
40
50
N credit =
130 lb/ac
N credit =
190 lb/ac
N credit =
45 lb/ac

14. 2012 Corn Yield, Rock County, WI
Nitrogen Rate (lb/ac)
0 50 100 150 200 250
CornYield(bu/ac)
100
120
140
160
180
200
None
Radish
Radish+60

15. 2013 SOIL NITRATE (PPNT)
May 2013, Soil Nitrate @ Rock Co.
R
adish
(0-1’)R
adish
(1-2’)
R
adish+60
(0-1’)
R
adish+60
(1-2’)N
o
radish
(0-1’)N
o
radish
(1-2’)
Soilnitrate(ppm)
0
1
2
3
4
5
6
7
No N credit based on PPNT in 2013

16. 2013 Corn Yield
0 50 100 150 200 250
60
80
100
120
140
160
180
200
220
No Radish
Radish
Radish + 60N
CornYield(buac-1)
N Rate (lb ac-1)
Error bars represent standard error.

17. 2013 CORN YIELDS
WASHINGTON COUNTY, WI
NO-TILL CORN FOLLOWING WINTER WHEAT
No effect of radish on yield or response to N in 2012 as well.

18.  Across six site years, we have not been able to
determine a nitrogen credit from radish with N
response yield data.
 Is it doing something to the soil – how often will this
result in a yield increase?
 Most likely will be part of mixtures rather than pure
stands.
RADISH CONCLUSIONS

19.  Reduces soil erosion
 Reduces nitrate leaching
 Potential to use as a forage crop
GRASSES

20.  Continuous corn silage w/ fall manure application
(10,000 gal/ac of liquid dairy manure)
 Fall-planted winter rye (90 lb live seed/ac)
1) No cover crop
2) Winter rye as a cover crop
3) Winter rye as a forage crop (ryelage)
STUDY DESIGN

21. RYE COVER CROP ABOVEGROUND BIOMASS
Termination date
4/12/12 5/1/13 5/12/14
Drymatter,lb/ac
0
1000
2000
3000
4000
115 lb N/ac
11 lb N/ac 11 lb N/ac

22. RYELAGE ABOVEGROUND BIOMASS
Harvest date
5/10/12 5/21/13 5/30/14
Drymatter,lb/ac
0
2000
4000
6000
125 lb N/ac
65 lb N/ac73 lb N/ac

23. SOIL NITRATE AT CORN PLANTING
2012
No
CC
Rye
CC
Ryelage
SoilNO3
--N,ppm
0
5
10
15
20
25
2013
No
CC
Rye
CC
Ryelage
2014
Cover Crop Treatment
No
CC
Rye
CC
Ryelage
0
5
10
15
20
25
0-12"
12-24"

24. Corn silage yield, 2012
Arlington, WI
N rate, lb N/ac
60 100 160
Yield(65%moisture),ton/ac
0
5
10
15
20
25
30
No CC
Rye CC
Ryelage
RESULTS
Ryelage = 13 ton/ac

25. RESULTS
Total forage:
Corn silage
+ Ryelage
Corn silage yield, 2012
Arlington, WI
N rate, lb N/ac
60 100 160
Yield(65%moisture),ton/ac
0
5
10
15
20
25
30
No CC
Rye CC
Ryelage

26. Corn silage yield, 2013
Arlington, WI
N rate, lb N/ac
60 100 160
Yield(65%moisture),ton/ac
15
20
25
30
35
No CC
Rye CC
Ryelage
RESULTS
Ryelage = 6.5 ton/ac

27. RESULTS
Total forage:
Corn silage
+ Ryelage
Corn silage yield, 2013
Arlington, WI
N rate, lb N/ac
60 100 160
Yield(65%moisture),ton/ac
15
20
25
30
35
No CC
Rye CC
Ryelage

28. N rate, lb N/ac
60 100 160
Yield(65%moisture),ton/ac
20
25
30
35
40
No CC
Rye CC
Ryelage
Corn silage yield, 2014
Arlington, WI
Error bars represent standard error.
RESULTS
Ryelage = 5.8 ton/ac

29. RESULTS
N rate, lb N/ac
60 100 160
Yield(65%moisture),ton/ac
20
25
30
35
40
No CC
Rye CC
Ryelage
Total forage:
Corn silage
+ Ryelage
Corn silage yield, 2014
Arlington, WI
Error bars represent standard error.

30.  Winter rye as a cover crop did not affect corn silage
yield
 Winter rye as a forage crop reduced corn silage yield
in 2 of 3 years.
Led to greater total production in 2 of 3 years and the
same amount of total production in 1 of 3 years
CONCLUSIONS

31. Clovers provide the clearest value (N fertilizer) –
but can you get clovers into Iowa cropping
systems?
The benefits of radish to corn crop are unclear
Rye, if killed early, provides good erosion control
and should not negatively impact corn yields
Potentially huge benefit of rye as a cover AND
forage but needs to be evaluated in all soil types.
HOW TO MAKE COVER CROPS PAY

32. QUESTIONS?
COMMENTS?
CONCERNS?