NPK ratios?

Leo A. Martin
Fri, 01 Feb 2008 17:32:27 PST
Another point about nitrification of ammonia by soil bacteria -- it
proceeds at higher rates as ambient temperatures rise.

A few years ago I attended a lecture by a soil scientist at the University
of Arizona Maricopa County Agricultural Extension. He explained that
ammonium in fertilizers applied the ground here when temperatures are over
about 90F will be completely metabolized and vanish within an hour.
Maricopa County includes Phoenix as well as Glendale, the site of the
upcoming Superbowl.

He told us to go ahead and use ammonium sulfate in the summer and not
worry about nitrogen burning our plants. (The sulfate is very helpful here
with our alkaline soils.)

But, in the winter, it is not very warm here. We can wear short pants only
about three quarters of the time. Soil bacteria don't do much with the
ammonium. In the winter he suggested using calcium nitrate for the winter
lawns people from the Midwest and California seem determined to grow here
in the desert.

Leo Martin
Phoenix Arizona USA

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