6. Nitrogen Management
- Corn grain removes approximately 0.67 lbs of nitrogen per bushel harvested, and stover production requires about 0.45 lbs of nitrogen for each bushel of grain produced.
Figure 5. Nitrogen rates (total lbs/acre N applied) of NCGA National Corn Yield Contest entries exceeding 300 bu/acre in 2020 and 5-year averages.
- This means that the total N needed for a 300 bu/acre corn crop is around 336 lbs/acre.
- Only a portion of this amount needs to be supplied by N fertilizer; N is also supplied by the soil through mineralization of soil organic matter.
- The N application rates of 300 bu/acre entries varied greatly; over half were in the range of 200 to 300 lbs/acre (Figure 5).
Figure 6. Nitrogen fertilizer application timing of NCGA National Corn Yield Contest entries exceeding 300 bu/acre in 2020 and 5-year averages.
- Timing of N fertilizer applications can be just as important as application rate. The less time there is between N application and crop uptake, the less likely N loss from the soil will limit crop yield (Figure 6).
- Nearly 90% of 300 bu/acre entries in 2020 included some form of in-season N application, either sidedressed or applied with irrigation.