Subject: Re: Describing N behavior

From: Carl Bannon <[email-masked]>
Date: Mon, 27 Feb 1995 16:34:59 -0500 (EST)

Hi,

Sorry about getting into this conversation late.  I was suprised to hear
that research on N behavior in some institutions would like to dis-regard
organic N because of its inherent complexities.  Our research and
extension programs have focused on using organic N to its greatest
potential and minimizing fertilizer N.  This is mostly because we are a
major dairy state that where alfalfa and corn rotations are dominant
cropping systems and manure is a problem in many situation because of
nutrient excesses in dairy farms.  This approach seems to be the focus of
most soil fertility research in dairy producing states.

While the PSNT (pre-sidedress nitrogen test) for corn is not a substitute for
poor soil or manure management it can help in nitrogen use decision making.
In fact demonstratin the PSNT on 111 fields here in Central NY has resulted
in a 50% decrease in N fertilizer use.  The economic savings averaged over
a $100 in fertilizer savings per PSNT taken, along with the environmental
benifit.  No their are not percise N applications that coincide with a
given PSNT value but it can help make sense out of the complex N system
that Nancy describes.

I also agree that we need to examine cropping systems that more
efficiently recycle N and reduce soil loss, ie grasslands ag.  But those
of us in extension need to work with farmers within their present
situation and goals and many times this involves corn silage and a lot of
manure.

Carl Bannon
Area Field Crops Specialist
Cornell Cooperative Extension
60 Central Avenue
PO Box 5590
Cortland, NY 13045
(607) 753-5077
[email-masked]