In article , Franz Heymann notfranz.
writes

I don't understand why you say " may go some way to replacing
NPK....."
Why not replace those elements completely? Moreover, my understanding
is that most farmers who use fertilisers tend to *overreplace* the
elements used by the crops.
Yes, they probably do. Nutrient replacement is not an exact science.

Also, there are fertilisers which, in addition to NPK, contain the
other elements needed for plant growth. As a matter of fact, I
suspect that simple fertilisers like Growmore do in fact contain
sufficient trace elements. The only reason only NPK concentrations
are declared is simply that that is all they have to do to comply with
the law.

There would be a better understanding of chemical fertilisers if their
additional properties were made known to gardeners.
--
Alan & Joan Gould - North Lincs.