Table 1.2-6. Nitrogen recommendations for agronomic crops.
These are base recommendations and should be adjusted for manure applications (see Manure Nutrient Management section).
| Crop (typical yield/A) |
Recommendation (lb N/unit of expected yield) |
Recommendation for typical yield (lb N/acre) |
Comments |
|---|---|---|---|
| Corn grain (130 bu/A) |
1 | 130 | For better N efficiency, delay application of the nitrogen until the corn is between 10 and 20 inches tall. If the field has a history of manure and/or legumes, delay all of the N. If there is no history of manure and/or legumes, split the N, applying one-third near to planting and delaying the balance. The PSNT can be used to refine N recommendations for corn, especially where manure is major nutrient source. Adjust this recommendation for any previous legume in the rotation (see Table 1.2-8). |
| Corn silage (21 ton/A) |
7 | 150 | For better N efficiency, delay application of the nitrogen until the corn is between 10 and 20 inches tall. If the field has a history of manure and/or legumes, delay all of the N. If there is no history of manure and/or legumes, split the N, applying one-third near to planting and delaying the balance. The PSNT can be used to refine N recommendations for corn, especially where manure is major nutrient source. Adjust this recommendation for any previous legume in the rotation (see Table 1.2-8). |
| Grain sorghum (125 bu/A) |
0.75 | 95 | Adjust this recommendation for any previous legume in the rotation (see Table 1.2-8) |
| Forage sorghum (21 ton/A) |
7 | 150 | Adjust this recommendation for any previous legume in the rotation (see Table 1.2-8) |
| Oats (80 bu/A) |
0.8 | 65 | Apply the N with any other fertilizer before planting. Be sure to account for residual N from previous manure applications. |
| Wheat/Rye (60 bu/A) |
1 | 60 | If plants did not tiller well, apply N by mid-march; otherwise, apply any time up to growth stage 5. Be sure to account for residual N from previous manure applications. |
| Barley (80 bu/A) |
0.8 | 65 | If plants did not tiller well, apply N by mid-march; otherwise, apply any time up to growth stage 5. Be sure to account for residual N from previous manure applications. |
| Small grain silage (6 ton/A) |
17 | 100 | Apply at greenup in the spring. |
| Grass hay (4 ton/A) |
50 | 200 | Split the recommendation and apply it based on the expected yield for each cutting. For grass-legume mixtures, if the legume is more than 50% of the stand, the field should be managed as a legume; thus, no nitrogen is recommended. |