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Nutrient Removal for Field Crops in Ohio

ANR-96
Agriculture and Natural Resources
Date: 
04/13/2021
Harold Watters, Associate Professor and Field Specialist, Agronomic Systems

An update for nutrient recommendations for Ohio's major field crops (corn, soybean, wheat, and alfalfa) was published in 2020 as the Tri-State Fertilizer Recommendations for Corn, Soybean, Wheat, and Alfalfa. This fact sheet builds on that information, and expands it to include recommendations for other agronomic crops grown in Ohio.

Crop Nutrient Management Philosophy Blue sky and corn field

The current philosophy in Ohio for crop nutrient management is to apply phosphorus (P) and potassium (K) fertilizer or manure equivalent at crop removal rates. Additionally, if soil test levels of P and K are below the critical level, then a "Buildup" recommendation would be considered to increase soil test levels into the "Maintenance" range. 

The values in Table 1 are the averages for the crops listed and were gathered from neighboring state and national databases. See the references section of this fact sheet for a list of sources.

  • See Table 2 for the maintenance ranges and Table 3 for calculating new fertilizer recommendations. Once in the maintenance range, crop removal would be the recommendation for P2O5; the K2O recommendation would be crop removal plus 20 lbs/A of additional K2O. If soil test levels are at or above their respective maintenance limit, then no further P2O5 or K2O would be applied.
    • As stated above, these values are averages for the crop named. For more accurate numbers for a particular area and crop, send a sample to a lab for testing and use that value for crop removal.
  • Critical soil test levels have not been recently evaluated for the additional crops beyond corn, soybean, wheat, and alfalfa listed in this fact sheet. It is reasonable to assume that critical soil test values used for crops listed here, and in the updated Tri-State Fertilizer Recommendations, can be used as guidance for the small grain or forage crops listed in Table 2. 
  • The nitrogen (N) recommendations for Ohio field crops come from several sources. Generally, these recommendations are based on yield goal, economics, or previous crop—not on crop removal for nitrogen, as shown in Table 1.
  • No tables are shown for vegetable crops. Please use the information found in the Resources section of this fact sheet.
Table 1. Regional averages of nutrient removal in harvested portions of agronomic crops.
Crop Average nutrient removal
Grains Unit N P2O5 K2O
Barley (grain) lb/bu 0.94 0.39 0.51
Barley (straw) lb/ton 14.7 3.4 48.7
Buckwheat lb/bu 1.12 0.22 0.23
Canola lb/bu 2.35 0.76 0.58
Corn1 lb/bu   0.35 0.20
Millet (grain) lb/bu 1.18 0.27 0.28
Oats lb/bu 0.65 0.36 0.44
Oat (straw) lb/ton 14.2 3.7 51.0
Rye (grain) lb/bu 4.72 0.48 0.60
Rye (straw) lb/ton 11.3 3.1 22.9
Grain sorghum lb/bu 0.92 0.39 0.39
Soybean1 lb/bu   0.80 1.15
Spelt lb/bu 0.98 0.27 0.25*
Sunflower lb/cwt 2.66 0.92 1.06
Wheat (grain)1 lb/bu   0.50 0.25
Wheat (straw)1 lb/ton   3.70 29.0
Forages2   N P2O5 K2O
Alfalfa1 100%DM lb/ton   12 49
Legume hay lb/ton 47.5 10.7 41.0
Legume-grass hay lb/ton 39.0 12.0 40.3
Cool-season grass hay lb/ton 35.4 12.0 48.1
Corn stover lb/ton 18.9 6.3 32.6
Corn silage1 35%DM lb/ton   3.1 7.3
Sudan/Sorghum-sudangrass hay lb/ton 30.7 9.4 45.1
Sudan/Sorghum-sudangrass silage lb/ton 36.1 12.5 57.6

*from one state value.
1 Tri-State Fertilizer Recommendations for Corn, Soybean, Wheat, and Alfalfa
2 Forages/hay is presented as 10% moisture content except where noted.

Table 2. 1Recommended Mehlich-3 soil test phosphorus and potassium levels (critical level–maintenance limit) for field crops in the tri-state region.
    Mehlich-3 Potassium Maintenance Range
Crop Mehlich-3 Phosphorus Sandy soils Loam and clay soils
  Maintenance Range (CEC <5 meq/ 100g) (CEC >5 meq/ 100g)
Corn (grain or forage), Soybean 20–40 ppm 100–130 ppm 120–170 ppm
Wheat, Alfalfa 30–50 ppm 100–130 ppm 120–170 ppm

1 Tri-State Fertilizer Recommendations for Corn, Soybean, Wheat, and Alfalfa

Table 3. 1Equations used for calculating new fertilizer recommendations. (Michigan potassium equations are identical to those of Indiana and Ohio, except they do not include an additional 20 lbs of K2O added to crop nutrient removal.)
Phosphorus (lbs P2O5/ acre to apply)
Maintenance range Yield × Nutrient Removal
Build-Up range (Yield × Nutrient Removal) + [(CL – STP) x 5]
Potassium for Indiana and Ohio (lbs K2O/ acre to apply)
Maintenance range (grain crops) (Yield × Nutrient Removal) + 20
Maintenance range (forage crops) [(Yield × Nutrient Removal) + 20] - [((Yield × Nutrient Removal) + 20) x (STK – CL)/50]
Build-Up range [(Yield × Nutrient Removal) + 20] + [(CL – STK) × (1 + (0.05 x CEC))]
Potassium for Michigan (lbs K2O/ acre to apply)
Maintenance range (grain crops) Yield × Nutrient Removal
Maintenance range (forage crops) (Yield × Nutrient Removal) - [(Yield × Nutrient Removal) x (STK – CL)/50]
Build-Up range (Yield × Nutrient Removal) + [(CL – STK) × (1 + (0.05 x CEC))]

1 Tri-State Fertilizer Recommendations for Corn, Soybean, Wheat, and Alfalfa    

Nitrogen Recommendations

For corn, Ohio uses the Corn Nitrogen Rate Calculator based at Iowa State University. A significant amount of Ohio farm trial work went into the Iowa recommendations. The rates are based on an economic model and vary with corn and nitrogen prices, as shown in Table 4 below.

Table 4. Recommended nitrogen rates (lb nitrogen/acre) for corn following soybean, based on price of corn grain and nitrogen fertilizer.
  Price of Nitrogen Fertilizer ($/ lb)
Price/ bushel corn $0.30 $0.35 $0.40 $0.45 $0.50
$3.25 185 176 168 162 155
$3.50 187 180 173 166 160
$3.75 191 184 176 170 164
$4.00 195 186 180 174 168
$4.25 199 190 184 177 171
$4.50 200 193 185 180 175


Recommendations for wheat, a winter crop, are based on the yield goal; in the winter season, dramatic mineralization of organic matter is not expected, and thus does not supply much nitrogen.These recommendations are shown in Table 5 and in the Tri-State Fertilizer Recommendations.

Table 5. Nitrogen recommendations for wheat.
Wheat Yield Potential (bu/ac) Nitrogen rate (lb/ac)
60 70
70 80
80 90
90 110
100 120


Nitrogen recommendations for other small grains in Ohio follow the wheat model and are based on yield goal. Recommendations are shown in Table 6 and are in the Ohio Agronomy Guide, 15th edition.

Table 6. Recommended nitrogen for small grains
  Crop Yield Goal (bu/ac)
  Feed Barley 65 90 115
  Oats 90 120 150
    lb N/ac*
Spring application Feed Barley 55 95 135
Spring application Oats 60 90 125
Spring application Spelt 40 75 110
Spring application Rye 60 90 60

* Reduce nitrogen rate by 40 pounds per acre on dark colored soils.

Forage nitrogen needs can vary greatly depending on the amount of legume in the mixture. Yield potential drives those recommendations, which are shown in Table 7 and in the Ohio Agronomy Guide.

Table 7. Nitrogen rates recommended for perennial cool-season grass forages.
  Yield potential, ton/ac
Crop, Percent Legume 4 6 8
  Annual application (lb N/ac*)
Tall grass, less than 20% legume 100 140 180
Mixed tall grass-legume, 20 to 35% legume 50 90 130
Mixed tall-grass legume, greater than 35% legume 0 0 0

* Make split applications of nitrogen in the early spring and after the first harvest. Liquid nitrogen should be applied in early spring or immediately following foliage removal.

Nitrogen rates for annual forages (Table 8) are determined by yield goal and previous crop; since forages are a summer crop, mineralization of nitrogen will occur, contributing to nitrogen sources.

Table 8. Nitrogen recommendations for summer-annual grasses
  Yield goal (tons dry matter/ac)
Previous crop 3-4 5-6 6+
  lb N/ac*
Good legume stand (5 plants/sq ft) 0 0 40
Average legume stand (3 pl/sq ft) 0 40 80
Grass sod 60 100 140
Soybeans 70 110 150
Other 100 140 180

* Split applications of nitrogen should be made; half prior to seeding, and the remainder divided equally and applied after each cutting or grazing.

Additional information for forage nitrogen rates can be found in the Ohio Agronomy Guide, 15th edition; Chapter 7, Forage Production and Chapter 9, Pasture and Grazing Management.

References

Nutrient content of field crops used in Table 1. (Accessed April 6, 2020) Dairy One, Feed Composition Library: dairyone.com/services/forage-laboratory-services/feed-composition-library/

Nitrogen rates (Accessed April 6, 2020)

Resources

Nutrient content of vegetable crops (accessed April 7, 2020)

Contributors

Steve Culman, Associate Professor and State Specialist in Soil Fertility
R. Mark Sulc, Professor and State Specialist in Forages
Laura Lindsey, Associate Professor, Horticulture and Crop Science

Acknowledgments 

The author would like to thank the following for their time and encouragement while reviewing this publication:

Greg LaBarge, Professor and Field Specialist, Agronomic Systems
Lee Beers, Area Leader and Extension Educator, Agriculture and Natural Resources, Trumbull County
Christine Gelley, Extension Educator, Agriculture and Natural Resources, Noble County
Brad Bergefurd, Horticulture Specialist, Agriculture and Natural Resources, South Centers

Visit The Ohio State University Agronomic Crops Network at agcrops.osu.edu/home for additional information on this topic and more.

Topics: 
Ag Crops and Livestock
Tags: 
agronomy
nutrient removal of field crops
Program Area(s): 
Agriculture and Natural Resources
Originally posted Apr 13, 2021.
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