FieldScience | By Dr. Elizabeth Guertal
FORM, FUNCTION, FIT:
which nitrogen source
is right for you?
I
t's time to pick a nitrogen fertilizer source for
your sports field. How do you make
that decision? Advertisements frequently tout nitrogen (N) fertilizer
as the "slowest release," "the quickest greenup," or "the most available." Add technical
terms such as methylene urea, ureaformaldehyde and controlled-release polymer, and the
topic of nitrogen fertilizers starts to get com-
8 SportsTurf | October 2013
plicated indeed. But, it's really not. The basic
chemistries and manufacturing processes behind most of our commonly available N
sources fall into five to six major groups, and
you can sort out the ones you should use
(and when to use them) from there.
Let's discuss the groups:
soluble sources of n that are manufactured from inorganic (no carbon in the
source) n sources.
Sources of water-soluble N include
potassium nitrate (13-0-44, this and all
other analyses are always expressed as percent N-P2O5-K2O), ammonium sulfate
(21-0-0), and, if you can still find it, ammonium nitrate (34-0-0). [Note: Since
people are used to buying the analysis '340-0', some fertilizer dealers now sell a product with a '34-0-0' analysis that is actually
created from urea, or it may be a blend of
ammonium sulfate and urea. This is not an
issue, it is simply a way to provide an analysis (34-0-0) that people are familiar with
without having to deal with the legal complexities now associated with the sale of ammonium nitrate.] Any time you need a
rapid turfgrass response, be it greening or
growth, a soluble material should be in
your spreader or spray tank. Soluble fertilizers provide quick turf green-up, which may
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