Slow-Release Nitrogen Better ForWet Soil, MU Researcher Reports
COLUMBIA, MO.
The farm landscape can significantly influence
how crops respond to different types of
nitrogen fertilizer, said Doug Ludwig, University
of Missouri soil science graduate student.
Ludwig studied nitrogen-use efficiency in corn
at the MU Greenley Memorial Research Center
and found that slow-release fertilizers boosted
yields in low-lying areas prone to pooling water,
while conventional urea outperformed other fertilizers
on well-drained farm soils.
With soaring fertilizer costs, maximizing nitrogen
efficiency can add up to real savings for
farmers, Ludwig said. He presented his research
at the MU Greenley Research Center Field Day,
Aug. 7, near Novelty, Mo.
“The main thing this study is trying to determine
is how efficiently nitrogen is used by the
corn itself,” Ludwig said. “Farmers want to know
what they’re putting in and what they’re getting
out financially, because that's the biggest issue
with all these rising costs.”
Ludwig compared how corn planted at various
parts of the Greenley farm responded to four
types of nitrogen fertilizer: conventional urea;
urea with N-Serve, which inhibits denitrification;
urea with a urease inhibitor, which reduces nitrogen
lost to the air; and polymer-coated urea,
a slow-release fertilizer.
“We looked at how these products performed
in low-lying areas, sideslopes and summit
areas,” Ludwig said. “The biggest differences
were between conventional and polymer-coated
urea. On the summit, it was more cost-effective
to use conventional urea, whereas in low-lying
areas it was more cost-effective to use the slowrelease
fertilizer.”
In low-lying areas, the slow-release fertilizer
outperformed conventional urea by about 20
bushels per acre, he said. “We saw a huge response
in lower-lying areas – upwards of $80 per
acre more in profit over the conventional urea.”
In well-drained areas, it was almost the reverse,
Ludwig said. “Conventional urea outyielded
polymer-coated by up to $50 bushels per
acre because there was no loss to soil moisture.”
The results may help farmers develop more efficient
fertilizer management plans. For instance,
the initial cost of slow-release fertilizer
makes some farmers think twice about using it,
but selectively applying it in areas where it
works better than other fertilizers will ultimately
save money when corn yields are higher, Ludwig
said.
“It costs more to apply, but it’s not something
farmers are going to apply clear across the field
as a blanket treatment. They would just apply it
in certain areas where it works better,” he said.
“For $10 or $12 per acre, farmers could go out
with multi-bin spreader trucks and spread two
to three products on the same field.”
Ludwig will repeat the study this year. He said
the data eventually will help researchers develop
a precision agriculture system using digital
maps of farm fields and computer-based treatment
recommendations that will help farmers
maximize fertilizer efficiency.
“Understanding how these products differ
cost-wise is important, so farmers aren’t spending
money using products that aren’t needed,”
Ludwig said. “They will be glad they spent the
extra money at the beginning getting the right
products, when it maximizes their profits in the
end.” Δ