Winter Cereal Rye Cover Crop Effect on Cash Crop
Yield: Results from Long-Term On-Farm Research
Stefan Gailans
& Sarah Carlson
Practical Farmers of Iowa
ASA-CSSA-SSSA
Minneapolis, MN
November 17, 2015
Farmer-Cooperators:
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Bill Buman, Harlan
Randy Caviness, Greenfield
Jim Funcke, Jefferson
Devan Green, Conrad
Rick Juchems, Plainfield
Rob Davis & Darwin Pierce, Coon Rapids
Mark Pokorny, Clutier
George Schaefer, Kalona
Jerry Sindt, Holstein
Rob Stout, West Chester
Gary & Dave Nelson, Fort Dodge
Kelly Tobin, New Market
Co-PI: Iowa Learning Farms
• Jacqueline Comito, Liz Juchems &
Matthew Helmers
Funders:
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Leopold Center for Sustainable Agriculture
Iowa State Soil Conservation Committee
Iowa State University Extension & Outreach
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Practical Farmers On-Farm Research:
Randomized, paired strip trials
Water quality in Iowa in the news
Water Works requests damages in federal suit
(Des Moines Register, Mar. 16, 2015)
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Des Moines Water Works says it spent more than half a million dollars
removing nitrates from central Iowa drinking water this winter.
•
The public utility wants compensation for damages and a federal judgment
against 10 drainage districts within three counties. It says they pose "a
nuisance, a trespass; negligence … unconstitutional taking of rights."
http://www.agronext.iastate.edu/soilfertility/info/SP435.pdf
QUESTION: How does a cereal rye cover crop
affect corn and soybean yields?
First strips established in Fall 2008 at six
commercial farms.
12 participating farmers from 2008 – 2014
(7 remaining)
METHODS: Six farmers in corn for the 2014
growing season
Cover crop
planting
date
Cover crop
planting
method
Cereal rye
seeding
rate
(lb/ac)
Plainfield
(NE Iowa)
10/22/13
Drill
Coon Rapids
(westcentral
Iowa)
10/21/13
Clutier
(east-central
Iowa)
Termination
method
Cash
crop
Planting
date
50
Cultivate &
herbicide
Corn
5/18/14
Drill
60
Herbicide
Corn
5/6/14
10/14/13
Drill
112
Cultivate
Corn
5/2/14
Kalona
(SE Iowa)
11/1/13
Drill
84
Cultivate &
herbicide
Corn
5/10/14
West
Chester
(SE Iowa)
9/26/13
Aerial
90
Herbicide
Corn
5/9/14
New Market
(SW Iowa)
10/10/13
Drill
56
Herbicide
Corn
5/15/14
Location
With cover crop
Without cover crop
Corn yields with and without cover crop
Corn yield (bu/acre)
300
+
250
*
200
*
150
100
50
0
2009
*P
≤ ≤0.05
*P
0.05
++PP≤≤0.10
0.10
2010
2011
2012
2013
2014
Corn yields
2011-2014
2009-2010
3/10 siteyears
18/18 site-years
7/10 site-years
Cover crop resulted in:
Yield improvement
No change
Yield decline
Soybean yields with and without cover crop
Soybean yield (bu/acre)
80
*
*
70
With cover crop
Without cover crop
*
+
60
50
*
40
30
20
10
0
2009
* P ≤ 0.05
+ P ≤ 0.10
2010
2011
2012
2013
Soybean yields
2011-2013
2009-2010
1
site- 2/12 siteyear years
2/6 siteyears
4/6 site-years
9/12 site-years
Cover crop resulted in:
Yield improvement
No change
Yield decline
Cover crop effect on soil microbial activity?
(Solvita CO 2 -C burst [ppm])
Haney Test
Soil samples collected to 6 -inch depth in mid -June
Cover crop effect on soil microbial activity, 2015
(Solvita CO 2 -C burst [ppm])
Solvita CO2-C burst (ppm) ± SEM
200
180
160
140
120
100
Cover
80
No cover
60
40
20
0
Jefferson
Holstein
Corn
Plainfield
Kalona
West
Chester
Soybeans
New
Market
Coon
Rapids
Cover crop take homes…
Hoping my success will encourage others in our
watershed so that our water is cleaner and we
keep more of our nutrients in the soil, instead
of in the Gulf of Mexico.
-Rob Stout, West Chester (SE Iowa)
The study actually showed how easy it is to grow cover crops and make them
work for you. I would hope the information we are gathering will influence
others to grow cover crops to help replenish the loss we have seen in the
last few years of intense row crop farming.
-Rick Juchems, Plainfield (NE Iowa)
Cover crop take homes…
• Cereal rye cover crop has minimal effect on corn or
soybean yields when properly managed
• Farmers reported that in 42 of 46 site-years, properly
managed cover crops has little to no negative effect on
corn and soybean yield.
• Soybean yields actually increased in 4 site-years.
• Cover crop did not have a significant effect on soil health
indicator after 5-6 years of cover cropping
• Soil microbial activity determined by Solvita method
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Poster session 301; posterboard #501