Measuring N Needs
Better Results Reported When Nitrogen Is Applied To Wheat Following Greenseeker Tips
PRINCETON, KY.
Technology is fine tuning the application of
nitrogen on wheat, according to Dr. Lloyd
Murdock, University of Kentucky soil specialist
who has been working on the
Greenseeker for a number of years.
“The Greenseeker is a remote sensing device
that allows you to go through a wheat field and
sense the color and growth of the crop as you
go; and at the very same time you can apply the
amount of nitrogen to that crop that the remote
sensing device says that you need,” he explained.
“We tested the Greenseeker for a number of
years. Early in our testing we found that algorithms
(formulas) we used to make the nitrogen
recommendations just didn’t work. They were
devised from other states quite a distance away
and did not apply to this area.
“So we decided we either had to make one for
ourselves or just give it up,” Murdock said.
“Then we went through five years of work and
developed algorithms for the state of Kentucky
and for this part of the United States; then we
field tested them over the last four years and
found they did very well.
“In every field that we tested the Kentucky algorithms
for the use of remote sensing to apply
variable rate nitrogen, it outperformed the flat
rate,” he noted. “The flat rate recommendation
was made by wheat consultants that do this all
the time and do a very good job, so we compared
the variable rate nitrogen application against
the best. The remote sensing and variable rate
nitrogen application rate was a little bit higher
in nitrogen in most cases. In some cases it was
almost the same but it distributed the nitrogen
easier or more evenly across the field and also
some years in some fields we actually got a better
recommendation from the Greenseeker than
we did from the consultants.”
With those two gains combined, a four bushel
gain was realized using variable rate nitrogen.
By applying about 10 pounds more nitrogen
and calculating the difference between those
two it was a gain of about $16 per acre. That’s
using $6 wheat.
“When we tested wheat grown after harvesting
soybeans using variable rate nitrogen applied at
Feekes 6, we actually gained a lot more than the
wheat planted after corn,” he said. “We gained
about 17-18 bushels for using the variable rate
nitrogen; and the gains were like $90 per acre.
I hate to talk about those numbers, it’s higher
than I would expect to get and I’m reluctant to
tell you, but that’s what we got. I don’t think
everybody is going to get that by any means, but
it does speak well for that method and for that
technology.”
Murdock’s take home message from this is
that farmers will have to embrace this high
technology in the application of nitrogen eventually,
especially on wheat.
“It’s going to be more difficult on corn although
it was used on corn and was helpful; but
on wheat it’s easy to do, it’s basically just applying
your nitrogen with that new technology
and we have more farmers using it all the time,”
he said. Δ
BETTY VALLE GEGG-NAEGER: Senior Staff
Writer, MidAmerica Farmer Grower