Supporting the Right Time and Right Rate
Splitting nitrogen into multiple applications across the season improves efficiency, crop uptake, and environmental protection.
What It Is
Instead of applying all nitrogen at planting, split applications distribute nutrients during key crop growth stages. This ensures nitrogen is available when crops — especially corn — need it most, while reducing the risk of losses through denitrification, runoff, or leaching.
How It Works
- Early-season → Apply part of the nitrogen at planting.
- Mid-season (V6–V8 growth stages) → Sidedress nitrogen when corn demand peaks.
- Reproductive stage → Nitrogen reallocates into ears and grain, where ~70% of the plant’s nitrogen ends up by harvest.
This timing supports the Right Rate and Right Time principles by matching nitrogen supply with crop demand.
Proven Benefits
- More efficient use of nitrogen inputs — reducing waste and increasing ROI.
- Reduced risk of environmental loss compared to applying all nitrogen up-front.
- Flexibility to adapt to weather and early-season conditions before committing all inputs.
Decision Tools for Split Nitrogen
- Pre-Sidedress Nitrate Test (PSNT): Estimates soil nitrate levels just before major crop demand to decide if more N is needed.
- Plant Tissue Tests: Measure chlorophyll in corn leaves to detect nitrogen deficiencies and adjust applications.
- Nitrogen-Rich Check Strips: Provide reference points for field comparisons using PSNT, tissue tests, or satellite imagery.
Getting Started
Work with your advisor to plan a split-application strategy tailored to your soils, crops, and management system. Incorporate decision tools like PSNT or tissue testing to refine your approach.
Resources:
- Cornell University’s Nutrient Management Spear Program
- University of Delaware Extension: Pre-sidedress Nitrate Test Factsheet
- Penn State Extension: Chlorophyll Meter Test Factsheet
