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
Nitrogen (N) fertilizer guidelines can be based on the results of the soil nitrate-nitrogen (NO3 -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 (NO3 -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 NO3 -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.
Reviewed in 2022