Thanks Tom.

A measurement that combines parts per million with pounds per acre.
Sounds like something an engineer would dream up. It's still not clear
to me how it would relate to the concentration of nitrogen compounds in a
pond.

I'll admit you had me confused when you wrote "this is an Ag term." What
the heck does this have to do with silver (Ag)? Then realized that you
meant AGriculture.

What can I say ... I'm a chemist.

Rich


"Tom L. La Bron" wrote in
:

Hey gang,

I am not a chemist, but this is an Ag term.

If you would please, could some one forward this to Ingrid, since she
has had me blocked for years now, and we don't speak directly, but the
term NO3-N is a new way designating the relationship of the amounts of
nitrogen applied to fields and the resultant NO3 that remains after
the crop has been harvested. Ag people in numerous states in the
heartland have been working on this for years now, but it is a way of
watching and calibrating the the amounts of N fertilizer needed for
the next crop to prevent the buildup of nitrates and keep them out of
the water table amd out of run off.. It is measured in the 6 inch to
one foot levels of the soil all the way to the 3 foot depth of the
soil. Nitrates are still measured in ppm, and the N is measure in
pounds/acre. Charts are kept to show the coorelations and show the
amounts needed for a variety of crops.

HTH

Tom L.L.