In article i3QAb.10816$5g.7265@okepread04, JimO wrote:
Eh dont listen to Frank, iron in the fertilizer does decay (and no we arent
talking about radioactive decay) and breakdown into iron oxide when hit with
water. I think he read ALOT more into your question that what you asked.

Ok, perhaps some of my query was a tiny bit over the edge, but in the end
all I was asking for was clarification.

Yes, some fertilizers contain Iron, as well as some Gypsum products.

If this iron in the fertilizer hits concrete and water it will leave a rust
stain.


Water and air and blah blah blah oxidozes the iron and turns it to iron
oxide we like to call this rust.

How long it takes for the Iron in the mix to breakdown into iron oxide
probably depends on the size of the iron in the fertilizer. I've seen some
with fairly large pellets and some with what looks like shavings.

If the fertilizer contained iron _compounds_, or if you're looking for
how soluable it may be -- that will depend on factors such as particle size,
pH, and a host of other factors.

One additional troublesome factor (especially if it's "chunky") is that
some iron-bearing fertilizers (particularly Ironite) also contain(ed)
dangerous levels of heavy metals. Some farmers have lost use of their
fields from this. You might want to google this one.

HTH...
-frank
--