CROPSEY, Ill. — Heavy rainfall and ponded soils can take a
toll on a field’s nitrogen levels, and the amount lost is difficult to predict.
But there are steps that can be taken to determine if the
corn has enough nitrogen to reach its full potential by season’s end.
“With the spotty nature of all the rains we have experienced
the past couple of weeks, it is very uncertain about how much nitrogen may have
been lost,” said Dave Mowers, AIM (Agricultural Information Management) for the
Heartland consulting agronomist.
One way get a better handle on how much nitrogen remains for
this year’s crop is to conduct a pre-sidedress nitrate test.
“Using the PSNT we can analyze soil samples taken shortly
before sidedress nitrogen applications to check to see how much nitrogen is
required for the crop,” Mowers said.
He added that nitrates can be lost four ways:
* Leaching by water moving the nitrates down through the soil profile and
out of reach of plant roots or actual loss in the tile lines;
* Runoff or erosion carrying the nitrates off the fields and away from the
* Denitrification due to extended soil saturation where nitrogen is lost to
the atmosphere; and
* Excess nitrogen absorption to aid in decaying previous crop residues.
However, due to the extended freeze last winter, much of last year’s residues
still remain on fields.
AIM for the Heartland is among the firms offering PSNT
services by collecting and testing the samples and then make recommendations for