When it comes to optimizing crop performance, timing is everything—especially with nitrogen. Foliar feeding offers a powerful way to address in-season nutrient demands, but not all nitrogen sources behave the same once they hit the leaf surface.
Here’s why nitrogen at foliar timing matters, and why slow-release triazone N is often the superior choice compared to traditional options like melted urea or 28-0-0.
Why Use Foliar Nitrogen?
Crops often show visual nitrogen deficiency during key growth stages—especially under stress or when root uptake is limited. That’s where foliar applications come in: they provide a quick, direct boost of nitrogen that bypasses the soil and feeds the plant through its leaves.
Foliar nitrogen can:
- Correct mid-season deficiencies
- Boost chlorophyll production for better photosynthesis
- Improve protein formation and yield
- Support grain fill and seed development
But just because foliar nitrogen gets into the plant faster doesn’t mean all forms are equally effective—or safe.
The Problem with Standard Urea & 28-0-0
Many growers turn to melted urea or 28-0-0 for foliar nitrogen. While these products are inexpensive and readily available, they come with downsides when used as a foliar feed:
- Leaf Burn Risk
- These forms have a high salt index and can easily cause phytotoxicity, especially during warm or dry conditions.
- Volatility and Loss
- Conventional urea is prone to volatilization and can be quickly lost to the air if not stabilized or watered in.
- Short-Term Effectiveness
- Standard nitrogen sources absorb quickly—but also flush through the plant quickly, meaning multiple applications may be needed.
The Triazone Advantage: Slow-Release Efficiency
Enter urea-triazone nitrogen—a more advanced form of nitrogen that’s ideal for foliar timing. It’s the backbone of products like Super 72® and offers real advantages over traditional liquid N sources.
How It Works:
Triazone nitrogen contains a three-carbon ring structure that slowly breaks down over time, releasing nitrogen steadily rather than all at once. This gives you the benefit of both immediate availability and sustained feeding.
Advantages at Foliar Timing:
- Low Burn Risk:
Triazone has a low salt index, making it far safer on leaf tissue—even in warmer conditions or higher volumes. - Extended Release:
Rather than peaking and fading, triazone N delivers up to 30 days of consistent nitrogen, improving efficiency and reducing the need for reapplication. - Better Uptake, Less Loss:
It’s less volatile than urea and better retained on the leaf surface, especially when used with a surfactant or tank-mixed with other nutrients. - Compatibility with Other Nutrients:
Triazone formulations are often highly compatible with micronutrients or crop protection products, making them a smart addition to foliar passes you’re already making.
Real-World Use: Super 72® at Foliar Timing
Super 72® from The Andersons is a standout performer at foliar timing. It contains:
- 28% total nitrogen, with 72% as slow-release triazone
- Liquid formulation that’s safe for foliar or soil use
- Low salt index, stable down to 0°F
- Packaging in 2.5-gal jugs, drums, totes, and bulk
It’s a high-efficiency option for row crops, cereals, and specialty crops that need nitrogen support during peak growth stages—without the downsides of conventional N sources.
Learn more about Super 72® here.
When to Apply Foliar Nitrogen
Foliar nitrogen is most effective when:
- Crops show visible N deficiency (light green, pale yellow)
- Root activity is limited due to cold or compacted soils
- You’re looking to support photosynthesis and grain fill
- Tissue tests show suboptimal N levels in vegetative stages
Foliar application is especially useful during:
- V5–V7 stages in corn
- Flag leaf and boot stage in wheat
- Pre-bloom or early bloom in many broadleaf crops
Final Thoughts
Nitrogen at foliar timing can help your crops push through critical growth stages—but not all N sources are created equal. While 28-0-0 and melted urea may be cheaper upfront, they often fall short in terms of safety, efficiency, and staying power.
For a smarter solution, consider a slow-release triazone product like Super 72® that delivers nitrogen efficiently, reduces burn risk, and keeps feeding your crop long after application.
Need help choosing the right foliar nitrogen strategy?
Reach out to the AgTek360 team—we’re here to help you grow stronger, smarter, and more sustainably.
