If you didn’t apply anhydrous ammonia last fall, you’re likely getting somewhat anxious. That’s understandable coming off the previous spring when wet, cold conditions not only prevented preplant anhydrous applications, but also delayed planting well beyond the ideal time across most of the Corn Belt.
Aside from factors largely out of our control, fall-applied nitrogen applications are on the decline. Agronomic, economic and environmental factors have led farmers away from fall in favor of spring preplant, early-summer sidedress and top-dress applications as advances in fertilizer formulations and equipment offer more flexibility as to when nitrogen — in various forms — can be efficiently applied.
Today, little, if any, fall application is occurring in southern Illinois and Indiana, due largely to increasing incidence of warmer fall temperature.
Although farmers appear to be reaping economic benefits from spring-applied N — including more efficient N use and crop uptake — the increase in spring-applied N applications puts more pressure on growers during a time of year that is already full of anxiety.
As we learned from last year — and nearly every spring prior, for that matter — weather has always been the biggest unknown. Wet soil conditions tempt farmers to apply N in less-than-ideal conditions.
Entering fields in wet conditions increases soil compaction and ultimately affects crop emergence and eventually yield. Additionally, there’s a greater risk of nitrogen leaching as the frequency of extreme rain events is higher during spring and early summer months.
Using a nitrification inhibitor such as N-Serve or Instinct nitrogen stabilizer is proven to impede the leaching and denitrification process, making more applied nitrogen available to the crop longer into the growing season.
Apply Preplant Anhydrous And Plant Wisely
A common concern for farmers is how soon corn can be planted following a spring application of anhydrous ammonia to avoid injury. Like much about farming, there’s no standard answer.
Crop injury can be avoided, or at the very least minimized, by applying anhydrous at least 7 inches deep and at a slight angle to the row. It’s important to achieve a good seal of the injection track to avoid ammonia placed in or movement into the corn root zone.
Movement from the initial injection site is more likely to occur in coarse, dry or cloddy soils. If injection sites aren’t sealing properly, install wing sealers directly above the outlet port on the injection system to help close the injection track, limit the size of the retention zone and reduce vertical movement of ammonia.
There’s no magical number, but it’s advisable to delay planting by as many days as possible after anhydrous ammonia applications to reduce incidence of crop injury. When that isn’t realistic, follow these planting tips to minimize injury:
• Do not plant directly over ammonia injection tracks.
• Use GPS technology to offset planter rows 4 to 6 inches or more from ammonia injection tracks to avoid root and seedling injury.
• Apply ammonia on an angle from the direction of crop planting to reduce crop row-length exposure to ammonia bands.
• Reduced application rate and narrower band spacing reduces the concentration of ammonia in each injection band.
• If the injection zone is offset away from future corn rows, an application can be done the same day as corn planting.
Lowering N rate is proven to minimize risk of injury. Splitting application timings between preplant and sidedress is an effective way to lower preplant anhydrous rates while giving the corn crop more continuous fertilizer feeding throughout the growing season.
Lastly, it’s important to not get in a hurry when applying anhydrous, regardless of your perceived time crunch. Excessive speed during application can make knives ride up in the soil and reduce depth of the injection zone.
What’s worse is that getting in a hurry often leads to accidents. Slow down, apply right and protect yourself.
Missed Preplant Application? Don’t Panic.
Although, in most cases, preplant applications of anhydrous ammonia are preferred, you still have options if impediments cause fertilizer application delays and planting takes precedence.
Be prepared with a Plan B, especially if conditions unpredictably would turn cool and wet. The plan should include alternate nitrogen sources such as UAN solutions or urea.
Sidedress and top-dress applications after crop emergence prove beneficial in maximizing yield by supplying a more continuous supply of nutrients when the corn crop needs it most.
® Trademarks of Dow AgroSciences, DuPont or Pioneer, and their affiliated companies or their respective owners. Instinct is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Do not fall-apply anhydrous ammonia south of Highway 16 in the state of Illinois. Always read and follow label directions. © 2020 Corteva.