Previous Crop and Cover Crop Effects on Corn Nitrogen...
Transcript of Previous Crop and Cover Crop Effects on Corn Nitrogen...
Previous Crop and Cover Crop Effects on Corn
Nitrogen Response
1Department of Soil, Water, & Climate, 2Southern Research and Outreach Center
MVTL Agronomy Update Meeting
January 30, 2020
New Ulm, MN
Carl Rosen1
Vince Fritz2
Charlie Rohwer2
James Crants1
Matt McNearney1
Background and Topics Covered
• Benefits and risks of a rye cover crop
• Sweet corn N rate, timing, and source study
– motivation for previous crop study
• Previous crop establishment to determine N credits
• Field corn N response following various previous crops
Why Plant Cover Crops?• Provides soil cover for extended period in the fall and spring
• Reduces runoff and wind erosion
• Captures residual nutrients (esp. N) to prevent leaching
• Outcompetes/controls weeds
• Potentially suppresses some insects and diseases
• Adds biomass and carbon (& nitrogen if a legume)
• Stimulates soil microbial activity
• Over time can improve soil aggregation
• Of the non-legume cover crops available, cereal rye is the easiest to establish and grow under Minnesota conditions
https://www.sare.org/Learning-Center/Books/Managing-Cover-Crops-Profitably-3rd-Edition/Text-Version/Nonlegume-Cover-Crops/Cereal-Rye
Cover Crop (Rye) Challenges for Corn
• Short time for seeding and stand establishment
– Seed into corn or soybeans before harvest (timely rain needed)
• Sometimes more diseases and pests
• Poor corn stand; Allelopathy? Lots of debate
– Chemical, physical or biological?
• Yield drag
– Termination date
– C/N ratio
– Environmental conditions
https://agfuse.com/article/how-to-protect-corn-yields-following-cereal-rye
Yield Advantage of Corn Following CC vs. No CC
https://www.iasoybeans.com/upl/downloads/publications/long-term-cover-crop-trials.pdf
15 Sites in Iowa in 2017 and 2018
Termination Date is Important – Illinois Study
https://www.dekalbasgrowdeltapine.com/en-us/agronomy/influence-of-the-timing-of-cereal-rye-cover-crop-termination-on-corn-yield.html
-26 -15 0 +7 Photos taken 6/11
Overall Assessment of a Rye CC for Corn
• Use of a winter rye CC can result in reduced or increased corn yields
• Management is important to maintain yields
• Late termination tends to result in lower yields
– Germination effects
– N effects
– Diseases
– Allelopathy
https://agfuse.com/article/how-to-protect-corn-yields-following-cereal-rye
What About CCs Following Sweet Corn?
• About 120,000 acres grown in MN for processing
• In rotation with soybeans and field corn
• Harvest starts early August until mid-late September
• Time and opportunity to establish a cover crop
https://agfuse.com/article/how-to-protect-corn-yields-following-cereal-rye
Previous N Rate Sweet Corn Study - SROC
• Three hybrids– GSS 1477
– DMC 21-84
– GM Code 646
• Two plant populations– 22,000 plants/A
– 28,000 plants/A
• Two planting dates– May
– June
• Six nitrogen treatments
1. 0 (no N applied),
2. 60 lb N/A applied preplant as urea,
3. 120 lb N/A applied preplant as urea,
4. 180 lb N/A applied preplant as urea,
5. 120 lb N/A applied preplant as ESN
(Environmentally Smart Nitrogen,
Agrium Inc.),
6. 120 lb N/A as urea with 60 lb N/A
applied preplant and 60 lb N/A applied
at V6-8.
Green Yield as Affected by N Treatment
and Plant Population Yield increased with
increasing N rate at both
populations;
An N rate between 120 and
180 lb N/A was required
Adequate N is necessary to
support yields at the higher
plant population
No difference in yield due to
N timing or N source
N Uptake as Affected by N Treatment and
Plant PopulationN uptake increased with
increasing N rate at both
populations;
N uptake was greater at the
higher plant population
No difference in N uptake
due to N timing or N source
50
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0 50 100 150 200
Pe
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N u
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N applied (lbs/ac)
Urea
ESN
Split
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b bc bcd
cd d
Proportion of N in Stover as Affected
by N Treatment
At optimum N rates,
57% to 59% of the
N taken up remains
in the stover
C:N ratio of ~ 32
Overall Summary from Sweet Corn N Study
• Optimal N rate for sweet corn following soybeans in a dryland high OM
soil was between 120 -180 lbs N/A; this is higher than current N
recommendations of 110 lbs N/A
• Split N applications and use of coated urea resulted in similar yields
compared to preplant applied urea
• About 58% of the N taken up by sweet corn was still in the stover at
harvest = 60-70 lbs N/A; C:N ratio ~ 30-40
• Can N rates be lowered in a subsequent corn crop?
Nitrogen Credit Study for Field Corn
• Objectives: – To assess the effect of sweet corn as a previous crop, relative to field
corn and soybean on field corn N response
– To determine the effect of a rye cover following sweet corn on field corn N response
• Can N rates be lowered for field corn if sweet corn is the previous crop? – Currently no N credit given for sweet corn
• First step was to establish the previous crops (and rye cover)
Methods
• Rotation crops established in 2017 & 2018
• Field corn N response was evaluated in 2018 & 2019
• Southern Research and Outreach Center (Waseca);
rainfed conditions
Previous Crops – 2017 and 2018
• Sweet Corn, Syngenta GSS1477– 140 lbs N/A
• Sweet Corn, Syngenta GSS1477 + rye cover crop– 140 lbs N/A
• Field corn, Nutech 5F-503AM (2017); 5F-196AM (2018)– 170 lbs N/A
• Soybean, Asgrow AG1733 (2017); Pioneer P15T46R2 (2018)– 0 lbs N/A
• 4 previous crops x 6 N treatments x 4 replications = 96 plots
101 201 301
0 #N 200 #N 100 #N
102 202 302
150 #N 250 #N 50 #N
103 203 303
100 #N 150 #N 200 #N
104 204 304
50 #N 0 #N 250 #N
105 205 305
100 #N 200 #N 0 #N
106 206 306
150 #N 50 #N 250 #N
107 207 307
150 #N 200 #N 0 #N
108 208 308
100 #N 250 #N 50 #N
109 209 309
0 #N 100 #N 150 #N
110 210 310
50 #N 250 #N 200 #N
111 211 311
150 #N 0 #N 200 #N
112 212 312
250 #N 100 #N 50 #N
113 213 313
150 #N 200 #N 100 #N
114 214 314
250 #N 50 #N 0 #N
115 215 315
100 #N 0 #N 150 #N
116 216 316
200 #N 250 #N 50 #N
117 217 317
250 #N 50 #N 0 #N
118 218 318
150 #N 200 #N 100 #N
119 219 319
50 #N 0 #N 250 #N
120 220 320
150 #N 100 #N 200 #N
121 221 321
150 #N 200 #N 100 #N
122 222 322
50 #N 250 #N 0 #N
123 223 323
0 #N 50 #N 150 #N
124 224 324
100 #N 250 #N 200 #N
125 225 325
0 #N 200 #N 250 #N
126 226 326
100 #N 50 #N 150 #N
127 227 327
250 #N 200 #N 100 #N
128 228 328
0 #N 150 #N 50 #N
129 229 329
200 #N 150 #N 50 #N
130 230 330
250 #N 0 #N 100 #N
131 231 331
200 #N 250 #N 50 #N
132 232 332
150 #N 0 #N 100 #N
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Precipitation and Temperature
Previous Crop Data Results - 2017
Crop Harvest yield Residue dry
yield (T/ac)
Residue N
uptake (lbs/ac;
left in field)
Residue C:N
Field corn 157 ± 16 bu/ac 5.1 ± 0.4 66.9 ±5.7 70.1 ± 4.2
Soybeans 48.2 ± 6.8 bu/ac 2.1 ± 0.1 50.0 ± 3.5 40.3 ± 2.1
Sweet corn 4.5 ± 1.2 T/ac 1.7 ± 0.1 59.7 ± 4.8 25.7 ± 2.5
Previous Crop Data Results - 2018
Crop Harvest yield Residue dry
yield (T/ac)
Residue N
uptake (lbs/ac;
left in field)
Residue C:N
Field corn 183 ± 19 bu/ac 3.7 ± 0.1 44.9 ± 1.6 76.8 ± 4.9
Soybeans 62.7 ± 2.7 bu/ac 2.0 ± 0.1 34.4 ± 4.2 58.8 ± 6.2
Sweet corn 6.2 ± 0.4 T/ac 2.4 ± 0.3 56.1 ± 18.4 40.4 ± 7.7
Rye Cover Crop Establishment & Management
• Sweet corn harvested August 15, 2017 & August 15, 2018
• Rye planted August 30, 2017 & September 11, 2018
• Sprayed with Roundup on May 10, 2018 & May 7, 2019
• Disked in 3 days later
Aug. 15, 2017
No-till grain drill
Sept. 7, 2017
Oct. 10, 2017
April 10, 2018
April 25, 2018
May 10, 2018
May 18, 2018
May 7, 2019
Results: Soil Nitrate-N (0-2 ft)
Fall 2017 & Spring 2018
CropFall 2017 nitrate-N
(ppm)
Spring 2018 nitrate-N
(ppm)
Field corn 2.8 ± 1.1 3.9 ± 0.6
Soybeans 3.8 ± 0.3 6.5 ± 2.8
Sweet corn 7.5 ± 0.9 6.4 ± 2.0
Sweet corn + rye 2.2 ± 0.4 3.1 ± 0.9
Soil Nitrate-N (0-2 ft)
Fall 2018 & Spring 2019
CropFall 2018 nitrate-N
(ppm)
Spring 2019 nitrate-N
(ppm)
Field corn 7.1 ± 1.0 8.7 ± 1.5
Soybeans 6.9 ± 1.2 8.1 ± 1.1
Sweet corn 5.8 ± 1.4 7.9 ± 1.9
Sweet corn + rye 6.9 ± 1.1 6.2 ± 1.2
Rye Dry Biomass and N Uptake (May 8, 2018)
1618+372 lbs/A
51+7 lbs N/A
C/N = 14
Rye Dry Biomass and N Uptake (May 7, 2019)
1887+779 lbs/A
56+21 lbs N/A
C/N = 14
N Treatments in 2018 & 20191. 0 lb N/A
2. 50 lb N/A
3. 100 lb N/A
4. 150 lb N/A
5. 200 lb N/A
6. 250 lb N/A• P, K, S all applied preplant and
incorporated with the N
Field corn planted:May 18, 2018 and May 15, 2019
101 201 301
0 #N 200 #N 100 #N
102 202 302
150 #N 250 #N 50 #N
103 203 303
100 #N 150 #N 200 #N
104 204 304
50 #N 0 #N 250 #N
105 205 305
100 #N 200 #N 0 #N
106 206 306
150 #N 50 #N 250 #N
107 207 307
150 #N 200 #N 0 #N
108 208 308
100 #N 250 #N 50 #N
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June 28, 2019
Previous crop - Field Corn Previous crop Sweet Corn
Field Corn N Response 2018 –
Previous Crop Effects on EONR
Rotation cropYield peak
(bu/ac)
EONR
(lbs/ac)
Field corn 185 252
Soybean 202 160
Sweet corn 207 180
Sweet corn + rye 205 161
N application rate (lbs/ac)
250
Field Corn N Response 2019 –
Previous Crop Effects on EONR
Rotation cropYield peak
(bu/ac)
EONR
(lbs/ac)
Field corn 191 256
Soybean 215 170
Sweet corn 219 166
Sweet corn + rye 225 191
250 188
Conclusions
• An N credit can be given when sweet corn is the previous
crop; possibly similar to or slightly less than soybean
• Adding a rye cover crop after sweet corn results in similar
or slightly less N credit than sweet corn or soybean
• N required for field corn following field corn was much
higher than expected
Next Steps• Data on field corn N uptake
from 2019 still to be analyzed
• Rotation crops & rye were grown for a study in 2020
• Plan is to repeat this study if funding is available
October 2019
Thank You & Questions?
Research Funding AcknowledgmentsMidwest Food Products Association
MN Agricultural Fertilizer Research and Education Council
Field Corn N Response 2018 –
Previous Crop Effects on EONR
Rotation cropYield plateau
(bu/ac)
EONR
(lbs/ac N)
Field corn 183 249
Soybean 198 144
Sweet corn 205 149
Sweet corn + rye 198 82
Field Corn N Response 2019 –
Previous Crop Effects on EONR
Rotation cropYield plateau
(bu/ac)
EONR
(lbs/ac)
Field corn 192 257
Soybean 211 126
Sweet corn 211 146
Sweet corn + rye 224 188