As we gear up for the growing season here at Peterson Farms Seed, I’ve been brainstorming ideas to improve our planting accuracy and our fertility program.
Over the winter, you probably reviewed last season and evaluated your system. How was your crop? Did you have any fertility issues? If so, were they related to saturated soils with loss? Or were they deficient due to higher populations and not feeding the crop?
In recent years, we’ve had wetter starts and drier finishes, which created some unique problems. In 2012, we could produce 180 bu corn on 120 lbs of Nitrogen due to better mobilization from the soil. In 2011 and 2013, with wet early seasons, it took 180lbs of N to reach 120 bu corn.
Nitrogen management really comes down to timing. The timing of the application is almost more important than the actual rate used. With increased early rainfall in heavier soils, denitrification becomes a major issue, losing the N to the atmosphere. Lighter soils normally have the opposite problem, losing N to leaching. Timing is critical in both of these scenarios, and it is important to apply the N as close to plant uptake as possible.
Large losses are easy to see, but how do we know if we’ve lost 15-30 lbs of N in our fields? Thankfully, there are some new tools available, providing instant nitrate tests to verify N levels. 360 SOILSCAN performs a soil nitrate analysis within minutes, so you can immediately see what is affecting yield and react accordingly to adjust your nutrient management plan in an accurate and timely manner.
While a field may show symptoms of N loss by becoming not as green, it is not always visual enough to catch. That’s why putting a “hot streak” of N–300lbs or more–in a strip, creating a non-deficient check to compare against is a good idea. These strips are easy to see from the air, by airplane or UAV.
We will be applying some late (V8-V12) Nitrogen strips with the 360 Y-DROP system this year. Last year our hot strips gave a 15 bu/acre advantage in the lesser drained soils we tested, showing yield that was lost due to denitrification. These late applied strips are mostly easily identified in the yield data at the end of the season.
With this year’s early planting, your pre-plant fertility program may be complete. But there are still opportunities to apply post-emerge, since nitrogen loss can be addressed after symptoms have been observed.
Hot streaks do not need to be applied in all of your fields. Choose some representative locations on your farm that give an overall indication, by soil type and drainage, of how your fertility program is working for you this summer.