Originally Posted by Smallaxe
This is exactly where I would like to be proven - right or wrong.
Milorganite is primarily manufactured for the purpose of recycling sewage, away, from the lake. [Lake Michigan]. Using it as fertilizer, the iron, is just a side effect as far as I can tell.
The second point that makes me believe that iron is a natural part of the equation is that - iron passes through the human body as readily as anything else.
It would make no sense for a sewage treatment plant to spend additional money to add iron - in the hopes of - enticing people to buy it. Especially when, very few people are even aware
of benefits of 'Fe', in the beautifying of the turf.
This is Milorganite's History page from their web site:
As you can see, not word 1 mentioned about iron past or present.
This specific question may be worth a call or two to their 800 number, what'ya think?
Oh, sure, I'm not debating whether iron is a naturally-occurring element or not. It has it's esteemed 26th place on the periodic table.
And no doubt there's X amount of digested Fe that is processed into Milorganite right along with the turds.
But is that X amount sufficient to total 4%?
As far as your point about relatively few people not knowing the benefits of Fe on turfgrass, I take exception to that.
'Ironite' has been seasonally marketed quite heavily nationwide the last couple of decades on radio & TV, newpapers & magazines since it left its early origin of golf course greens and entered the retail market:
Like Milorganite, Ironite perennially suffers from an onslaught of criticism from organic gardeners, especially, because of a problem with arsenic & lead at ppm levels.
But to the point....I think that because of super-aggressive & very well-timed marketing by a namesake company like Ironite, generally more folks know about the (short-term, cosmetic) benefits of iron than you may think.