Interesting read.
It appears the server or...? where I found a list of citations is temporarily down. I'll try later.
I sppose something of great interest is to determine how many different ways commercial phosphorus or phosphate fertilizers are processed and if one is safer than the other. This subject was brought up to me off forum by Spurr this morning. I'll try to source some information on this.
In my trials and errors as a grower, I came to the realization that high amounts of P were not necessary for good flower/fruit production but I was growing in soil. According to Spurr the amounts used in hydro are now vastly reduced. I hope this spreads because I am aware that quite a number of growers still cling to the concept that pumping the P in flower is the way to higher yields. I think this is particularly prevalent in growers using virtual hydroponics e.g. soiless media and soluble nutrients.
Grape old farmer, I believe you are correct that a P molecule is a P molecule on its own but what does it carry with it. Perhaps it is like the various products made from the opiate molecule, codiene, morphine, heroin, etc., each having a slightly different molecular bond. If a plant is deriving its P from an organic source like degraded plant matter or fish hydrolysate or even small amounts of soft rock phosphate or bone meal the P is made available through biological means (microbial or root acid excretions). In this way the uptake is natural and actively controlled. With chemical P treated with acid to make it available, I believe uptake is more passive.
[BTW when I used soft rock phosphate in soil an initial application was good for years. This is making me rethink SRP in tea]
