Nitrogen Fertilization for Maize: High Demand, Timing, and Organic N Credits
Grain maize (Körnermais) is grown on over 400,000 hectares in Germany, primarily in the warmer south and west. Maize has the highest nitrogen demand of all major German arable crops — both in total requirement and in N removal per tonne of grain — which makes precise N management especially important for both economics and DüV compliance.
Nitrogen Demand and Yield Response
Germany's average grain maize yield is around 10.2 t/ha (Destatis 2022). Maize removes approximately 16–17 kg N per tonne of grain produced (Setiyono et al. 2010; Hou et al. 2012). Advisory references commonly cite around 190 kg N/ha at reference yield for grain maize; current official DBE Bedarfswerte in several German states are higher. This is among the highest N advisory benchmarks of any German arable crop. The figures in this article are agronomic guidance; always verify with the applicable current state DBE table. The nitrogen response shows a strong Zone 1 up to 80 kg N/ha, with significant but diminishing returns from 80–180 kg N/ha, and near-zero gains above 180 kg N/ha.
Organic N: The Critical Accounting Factor
Maize is the crop most commonly fertilized with slurry, digestate, and manure. The DüV requires that all organic N inputs be accounted for using an availability coefficient (Anrechnungsfaktor). Typically, 60–75% of the ammonium-N in slurry is considered plant-available in the year of application. Farmers who apply 40 m³/ha of cattle slurry (typically ~150 kg total N/ha, ~80 kg available N/ha) should subtract this from the mineral N budget before calculating the remaining requirement.
Failing to account properly for organic N is one of the most common causes of over-fertilization and DüV compliance problems in maize.
Application Strategy
Maize receives nitrogen before or at sowing:
- Pre-sowing incorporation: mineral N or organic N incorporated before planting
- Side-dressing (BBCH 12–16): additional mineral N if pre-sowing was insufficient or weather delayed
The ideal timing aligns nitrogen with the rapid vegetative growth phase from BBCH 30 onward (6-leaf to heading stage). Late-planted maize should receive N earlier in the season to ensure it is plant-available during the key demand window (June–July).
DüV Timing and Red Zones
Maize cannot receive nitrogen after the stop date for N fertilization in autumn (typically October 1). In red zones, many farmers must reduce total N by 20% below the calculated requirement, which puts significant pressure on yield planning.
Conclusion
Maize nitrogen management requires careful accounting of all nitrogen inputs — mineral and organic — against the crop's high demand. Economic optimization, organic N crediting, and compliance with DüV limits must all be addressed simultaneously.
Calculate your maize N rate accounting for organic inputs: Open the NRate Calculator