Don’t Let Pre-plant N Applications Slow Down Planting

  • Mar 31
    Greg Stewart
    Don’t Let Pre-plant N Applications Slow Down Planting By Greg Stewart on March 31, 2015
    Categories: Grain Corn, Tips

    Ontario producers traditionally apply a significant amount of N as urea in the pre-plant window. To reduce ammonia volatilization, this urea needs to be incorporated—generally a single pass with a field cultivator is enough to accomplish this. While this is an effective system, it can at times slow corn planting progress. 2015 may present a planting window where no delays can be tolerated, so some backup plans should be considered. Fortunately, there is an ever-growing list of N application options that can reduce planting bottlenecks. These can include streamer nozzle applied UAN after planting with traditional spraying equipment and broadcasting granular urea with traditional or higher clearance equipment. 

    A couple of points to consider:

    Producers can apply UAN (28%) using streamer nozzles after planting and this window extends up to corn at the 4-leaf stage with only minor leaf burn but no resulting yield loss. From the 4-leaf stage to 8-leaf stage, burn starts to increase and some risk to yield is present. After the 8-leaf stage the UAN streamer approach looks too ugly (leaf burn) for most to stomach. Volatilization is a concern from surface applied urea but the UAN risk is significantly lower than that of granular urea. Reducing the risk of UAN volatilization with a product like Agrotain® Ultra is an option. If soils are wet at the surface when UAN is applied, the volatilization risk is higher and the odds of Agrotain® paying off go up.

    If you are considering applying granular urea on the surface after planting, the considerations are a bit different. That is, the risks of leaf burn are much less than UAN but the risk of volatilization losses from the surface applied granular product are much higher. With the right equipment, surface broadcasting of urea can have a fairly wide window, however, growers will need to be prepared to protect this urea from volatilization losses by treating the urea with Agrotain® or using a coated urea product like ESN®. Again the warning: an unprotected granular urea product spread on a damp soil with relatively warm temperatures will be at risk to significant N losses (i.e. 25%).

    If you like the options of post-planting granular urea but don’t want to spend the money on protecting, then you will have to play the “timing” game. This means wait until the soil surfaces are dry, the foliage is not damp from dew, and the forecast calls for rain within 5 days. Then go hard and hope the weather man comes through with at least a half inch of rain.

    Greg Stewart
    Maizex Seeds Agronomy Lead