My son and I have been thinking which in itself is dangerous. The past several years we have been back and forth on side dressing corn. For some of those years we have spun on urea as a planned operation. Other years we have put it all on up front. Our CEC's are in the very low teens (12-15) so the amount of N we can hold in the soil is limited. That said I'm not convinced 10# of N per point of CEC is a hard and fast rule. I've seen times when I've applied 200 pound of NH3 in the fall and no other application of N except for MAP or DAP and been very pleased with corn yields. 


For discussion I found a website that gives the 5 and 10 year average soil temperature on a particular date. ESN applied April 10 right ahead of the planter would be on average going into 53 degree soil. At that soil temperature 20% of your nitrogen would be available within 30 days, leaving 80% for later. On May 30, (50 days post planting)  the soil temperature would be (on average) 69 degrees and about 75 percent of the ESN has become available. 

Here is what we are wondering. Has anyone applied ESN pre-plant? Everything I read say the ESN isn't available immediately. It depends on temperature increases to begin releasing the nitrogen. Couldn't that work as a "side dress application applied before planting?"

Edit to add chart showing typical Nitrogen release from ESN. You will have to click on attachment as I couldn't get it to post. 

N release.pdf (1530KB - 71 downloads)