Cover Crop x N Rate Study

Dr. Shalamar Armstrong, lead PI

Objective and Summary: Evaluate corn response to nitrogen rate in cereal rye and Balansa clover cover crops with various seeding methods.

Trial info: Cover crops seeded in the fall of 2024 conventionally, full drill width and precision seeded with rows shut off for cash crops.  Corn planted into various cover crops and seeding methods and followed up with six nitrogen rates from zero to two hundred fifty pounds.  In addition Armstrong researchers measured cover crop biomass for nutrient content.  Armstrong crew pulled corn whole plant, leaf and ear samples for nutrient analysis. The team also measured NO2 gas emittance from the various treatments.

  • Treatment: Nitrogen and Cover Crop
  • Cover crop seeded: 9/18/2024
  • Planted: 5/19/2025
  • Sidedressed: 6/26/2025
  • Soil Type: Cobbsfork, Avonburg
  • Variety: P1136
  • Harvest Date: 10/14/2025
rain comparison

 

graph: dry yield vs nitrogen rate 

Economics

Cover Crop

Cover Crop Treatments
Cover Crop Treatment Variety lbs./acre $/lbs. $/acre
Full seeded Balansa Clover Fixation 5 $3.71 $18.55
Precision seeded Balansa Clover Fixation 2.5 $3.71 $9.28
Full seeded Cereal Rye Hazlet 45 $0.36 $16.20
Precision seeded Cereal Rye Hazlet 22.5 $0.36 $8.10
YIELD x Corn Price  less Nitrogen $  less Cover Crop Seed Cost
  • Nitrogen Price:  $0.76 
  • Corn Price:  $4.50

Nitrogen Rate

nitrogen rates costs for cover crops
Nitrogen Rate Conv. Balansa Prec. Balansa Conv. Cereal Rye Prec. Cereal Rye No Cover
0 $305.27 $303.49 $201.99 $214.02 $226.98
50 $367.46 $368.21 $217.84 $291.54 $299.26
100 $697.60 $631.48 $484.84 $540.37 $498.52
150 $879.47 $884.15 $728.99 $789.89 $810.18
200 $927.57 $907.61 $823.99 $900.33 $922.47
250 $900.25 $902.50 $908.29 $887.44 $820.43

Evaluation of Precision Planted Cover Crops 2021-2022

Dr. Shalamar Armstrong - Soil Ecosystem and Nutrient Dynamics laboratory (SEND Lab) (Note: One year of multi-year data)

More here

Treatment Cost With Nitrogen and Cover Crop

Treatment Cost With Nitrogen and Cover Crop
N Rate Conv. Basala Prec . Basala Conv. Rye Prec. Rye No Cover
0 $19 $9 $16 $8 $0
50 $57 $47 $54 $46 $38
100 $95 $85 $92 $84 $76
150 $133 $123 $130 $122 $114
200 $171 $161 $168 $160 $152
250 $209 $199 $206 $198 $190

Purdue 2025/2026 Farm Custom Rate Survey

  • Drill Cost per Acre:  $19.46
  • Spreader Cost per Acre:  $7.74
  • Nitrogen Application per Acre:  $14.58

Average Yield Per Treatment (Bu/Acre)

* Yield that share a letter are not significantly different
N Rate Conv. Basala Prec. Basala Conv. Rye Prec. Rye No Cover
0 72 IJ 70 IJ 48 KL 48 KL 50 KL
50 94 HI 92 HI 60 JK 73 IJ 77 IJ
100 176 EF 159 FG 128 GH 137 GH 129 GH
150 225 BC 224 BC 191 DE 203 CD 205 CD
200 244 A 238 AB 220 BC 236 AB 239 BC
250 246 A 245 A 248 A 241 A 225 BC

conventional seeding

Above: an example of conventional seeding

Precision seedingAbove: an example of Precision Seeding