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 | Recommendation (lbs N/unit of expected yield) |
Comments |
|---|---|---|
| Corn grain | 1 | 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. Adjust this recommendation for any previous legume in the rotation (see Table 1.2-8) and for residual N from previous manure applications (see Tables 1.2-14 and 1.2-15). The PSNT or chlorophyll meter test can be used to refine N recommendations for corn, especially where manure is major nutrient source. |
| Corn silage | 7 | 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. Adjust this recommendation for any previous legume in the rotation (see Table 1.2-8) and for residual N from previous manure applications (see Tables 1.2-14 and 1.2-15). The PSNT or chlorophyll meter test can be used to refine N recommendations for corn, especially where manure is major nutrient source. |
| Grain sorghum | 0.75 | Adjust the recommendation for any previous legume in the rotation (see Table 1.2-8) and for residual N from previous manure applications (see Tables 1.2-14 and 1.2-15). |
| Forage sorghum | 7 | Adjust the recommendation for any previous legume in the rotation (see Table 1.2-8) and for residual N from previous manure applications (see Tables 1.2-14 and 1.2-15). |
| Oats | 0.8 | Apply the N with any other fertilizer before planting. Adjust this recommendation for any residual N from previous manure applications (see Tables 1.2-14 and 1.2-15). |
| Wheat/rye | 1 | If plants did not tiller well, apply N by mid-March, otherwise apply any time up to growth stage 5. Adjust this recommendation for any residual N from previous manure applications (see Tables 1.2-14 and 1.2-15). |
| Barley | 0.8 | If plants did not tiller well, apply N by mid-March, otherwise apply any time up to growth stage 5. Adjust this recommendation for any residual N from previous manure applications (see Tables 1.2-14 and 1.2-15). |
| Small grain silage | 17 | Apply at greenup in the spring. |
| Grass hay | 50 | Split the nitrogen 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. If plants did not tiller well, apply N by mid-March, otherwise apply any time up to growth stage 5. Adjust this recommendation for any residual N from previous manure applications (see Tables 1.2-14 and 1.2-15). |