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Millet fertilizer guidelines

Millet is important in some farm enterprises in Minnesota. Fertilizer is an important production input for optimum yields. Recommendations for nitrogen, phosphate, and potash are summarized in the tables that follow.

Nitrogen 

Fertilizer Nitrogen guideline map. The western half of the map is shaded in gray.
Fertilizer N for western Minn.

Nitrogen (N) fertilizer guidelines can be based on the results of the soil nitrate-nitrogen (NO-N) test or the consideration of the combination of expected yield, previous crop, and soil organic matter content. The soil nitrate test is appropriate for western Minnesota.

When the soil nitrate test is used, the fertilizer N guidelines are calculated as follows:

  • Suggested N in lbs./acre = (0.035) (EY) - STN(0-24 in.) - Npc
  • Nitrogen formula variables:
    • EY = expected yield (lbs./acre)
    • STN = nitrate-nitrogen (NO-N) measured to a depth of 24 in. (lbs./acre)
    • Npc = amount of N supplied by the previous legume crop (lbs./acre).

The N fertilizer guidelines for production situations where the 0-24 inch soil NO-N test is not used are listed in the following nitrogen guidelines table. For most production situations, the N fertilizers should be broadcast and incorporated before planting. The N fertilizer can be applied in either dry or liquid form. There is no research to document that one form is superior to the other.

Nitrogen guidelines for millet

Crop grown last year Organic matter level* 1500-1900 lbs./acre 1901-2300 lbs./acre 2301-2700 lbs./acre 2701-3000 lbs./acre 3000+ lbs./acre
Alfalfa (4+ plants/ft2) Low 0 lbs N/acre 0 lbs N/acre 0 lbs N/acre 0 lbs N/acre 0 lbs N/acre
Alfalfa (4+ plants/ft2) Medium/High 0 0 0 0 0
Alfalfa (2-3 plants/ft2) Medium/High 0 0 0 20 40
Alfalfa (2-3 plants/ft2) Medium/High 0 0 0 0 20
Soybeans or Alfalfa (1 or less plants/ft2) Low 0 10 20 40 60
Soybeans or Alfalfa (1 or less plants/ft2) Medium/High 0 0 0 20 40
Edible beans, field peas Low 20 30 40 60 80
Edible beans, field peas Medium/High 0 10 20 40 60
Group 1 Crops Low 0 0 0 0 25
Group 1 Crops Medium/High 0 0 0 0 0
Group 2 Crops Low 40 50 60 80 100
Group 2 Crops Medium/High 20 30 40 60 80

*low = less than 3.0%; medium and high = 3.0% or more. Crops in Group 1: Alsike clover, birdsfoot trefoil, grass/legume hay, grass/legume pasture, fallow, red clover. Crops in Group 2: Barley, buckwheat, canola, corn, grass hay, grass pasture, oat, potato, rye, sorghum-sudan, sugar beet, sunflower, sweet corn, triticale, wheat.

Use the suggested nitrogen credits in the following table for crops that might precede millet in a crop rotation. Use these credits when the soil nitrate test is used.

Suggested nitrogen credits for various crops that might precede millet in a crop rotation

Previous crop First year N credit lbs. N/acre
Soybean 20
Edible beans, field peas 10
Harvested sweet clover 10
Harvested alfalfa1 or non-harvested sweet clover
4-5 plants/ft2) 75
2-3 plants/ft2) 50
1-2 plants/ft2) 25
1 or fewer plants/ft2) 0
Harvested red clover 35
Sugar beet
Yellow leaves at harvest 0
Light-green leaves at harvest 15-30
Dark-green leaves at harvest 60-80

If the third or fourth cutting was not harvested, add 20 lbs. N/acre to the N credits listed.

Suggested nitrogen credits when millet is grown 2 years after a legume crop

Previous legume crop Second year N credit lbs. N/acre
Alfalfa (4+ plants/ft2) 35
Non-harvested sweet clover 35
Alfalfa (2-3 plants/ft2) 25
Birdsfoot trefoil 25
Red clover 20

Phosphate and potash

The guidelines listed in the following tables are intended for broadcast application. The sensitivity of this crop to banded application of fertilizers is not known.

CAUTION: Do not apply N as urea (46-0-0) in contact with the seed at planting. Do not apply ammonium thiosulfate (12-0-0- 26) or boron in contact with the seed.

Phosphate fertilizer guidelines

Expected yield Bray-P1
Expected yield Olsen
0-5 ppm
0-3 ppm
6-10 ppm
4-7 ppm
11-15 ppm
8-11 ppm
16-20 ppm
12-15 ppm
21+ ppm
16+ ppm
1500-1900 lbs./acre 25 lbs./acre 20 lbs./acre 10 lbs./acre 0 lbs./acre 0 lbs./acre
1901-2300 lbs./acre 30 25 15 0 0
2301-2700 lbs./acre 40 25 15 0 0
2701-3100 lbs./acre 45 30 20 0 0
3100+ lbs./acre 45 35 20 0 0

Phosphate fertilizer guidelines (lbs. of P2O5 suggested to apply per acre) for millet production are based on either the Bray-P1 or Olsen soil methods test reported in parts per million (ppm). Use one of the following equations if a phosphate guideline for a specific soil test and a specific expected yield is desired:

  • P2O5rec = [0.0171 - (0.0085) (Bray P, ppm)] (Expected yield)
  • P2O5rec = [0.0171 - (0.00114) (Olsen P, ppm)] (Expected yield)

Potash fertilizer guidelines

Expected yield 0-40 ppm 41-80 ppm 81-120 ppm 121-160 ppm 160+ ppm
1500-1900 lbs./acre 45 lbs./acre 35 lbs./acre 20 lbs./acre 10 lbs./acre 0 lbs./acre
1901-2300 lbs./acre 55 40 25 10 0
2301-2700 lbs./acre 65 50 30 10 0
2701-3100 lbs./acre 75 55 35 15 0
3100+ lbs./acre 80 60 40 15 0

Potash fertilizer guidelines (lbs of K2O suggested to apply per acre) for millet production are based on the ammonium acetate potassium test reported in parts per million (ppm)Use the following equation if a potash guideline for a specific soil test and a specific expected yield is desired:

  • K2O rec = [0.03 - (0.00018) (Soil test K, ppm)] (Expected yield)

Other nutrients

There is no research evidence that suggests that sulfur and micronutrients are needed for the optimum production of millet. So we do not suggest adding these nutrients to a fertilizer program.

Authors: Daniel Kaiser, Extension nutrient management specialist, and Keith Piotrowski, director of the soil testing laboratory

Reviewed in 2022

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