Cool soil in most of the Corn Belt means a low risk of nitrogen loss for now, says Emerson Nafziger, University of Illinois Crop Sciences professor. Advising farmers on best nitrogen practices for this spring, Nafziger offers these observations and pointers.
- With the cold winter, fall-applied anhydrous ammonia is mostly still in the more stable ammonium form (NH4+) and has not yet mineralized into the more easily lost form of nitrate (NO3-). It will stay that way as long as soils temperatures stay below 50° F.
- Once ammonium turns into nitrate as soils warm, we only worry about losing it if it turns wet. If the tile lines aren’t running, there won’t be nitrogen loss even if the nitrogen is nitrate.
- Nitrogen stabilizers used last fall also remain in force due to low soil temps.
- Cool soils will dry slowly, and wet soils after planting could slow root access to nitrogen uptake.
- Delayed planting and/or slow growth would mean that nitrogen uptake will start later, so loss potential in May and June could still be a factor.
- Wet spring soils could make soil compaction more damaging to roots, slowing nitrogen intake.
- What appears to be nitrogen loss in wet soils can partly result from damaged roots.