Wet spring conditions can increase the risk for leaching, denitrification and volatilization losses of nitrogen.
Koch Agronomic Services gives perspective on how retailers and farmers can manage risk during a tight spring timeframe with environmental challenges. Here’s a series of scenarios…and click here for the full report.
Scenario One: Spring anhydrous ammonia
If time and logistics allow, apply nitrogen originally planned as pre-plant anhydrous ammonia, stabilized with Centuro nitrogen stabilizer. Centuro is designed to protect nitrogen from leaching and denitrification losses. A multi-state, multi-year study showed that spring applications of anhydrous with Centuro yielded 6 bu/acre of corn more than untreated spring anhydrous
Scenario Two: Spring Anhydrous is delayed or unavailable
If there could be a potential delay in the delivery and application of ammonia, a grower should consider the following as pre-plant alternatives:
All or a portion of the nitrogen can be applied as a weed and feed application with pre-plant, pre-emergence or burndown herbicide. Remember, broadcast UAN is subject to volatilization loss and should be treated with a urease inhibitor, such as Anvol nitrogen stabilizer.
All or a portion of the total nitrogen can be applied as broadcast urea. Volatilization losses with urea can approach 40% of applied nitrogen and should be protected with ANVOL.
All or a portion of the total nitrogen can be applied as broadcast SuperU fertilizer , which has the same nitrogen content as urea and features integrated dual inhibitors to minimize all three forms of nitrogen loss. Across 8 site-years with locations in Virginia, Kentucky, Illinois, and Tennessee, urea treated with ANVOL resulted in a 31 bu/acre corn yield advantage over untreated urea. 2
Scenario Three: Optimal planting date is near or passed
A 22-site year study on corn conducted by the University of Illinois showed corn yield was maximized when planted in mid-April to early May. Planting on May 10 reduced yield by 5% and yield decreased by almost 0.5% for every day planting was delayed beyond May 10 (through May 30)3. If soil conditions or delayed fertilizer availability pushes the planting window further out, growers should consider planting first and then applying nitrogen afterwards. Early post-planting nitrogen applications could be in the form of Centuro treated anhydrous ammonia, broadcast SuperU and urea or UAN treated with Anvol. Early nitrogen applications are subject to loss prior to the rapid vegetative growth stage of corn.
Split nitrogen applications may help mitigate yield impacts of early season nitrogen loss and ensure that nitrogen is available during grain fill. Two-thirds of the nitrogen can be applied as either Centuro-treated anhydrous ammonia, broadcast SuperU or urea treated with Anvol or injected UAN treated with Centuro or Anvol, either at planting or very early post-planting.
The remaining nitrogen can be applied as broadcast urea, dribbled UAN, injected UAN, or even injected anhydrous. Post-emergent surface applications of nitrogen as either urea or UAN are particularly vulnerable to volatilization loss and should be protected with a urease inhibitor, such as Anvol.
Delaying nitrogen applications beyond early vegetative stages may reduce yield potential, especially in high yielding environments.
Research has shown that early season nitrogen is important to optimize yield potential for the primordial ear. Delayed applications may limit yield potential and can also carry the risk of nitrogen never getting into the plant due to the increased likelihood of dry surface conditions as we move later into the growing season.