a question for soil chemists about phosphorus

I need to add some phosphorus to tomato seedlings. Steamed bone meal is relatively insoluble, I have heard, so sprinkling it on the top of the flats would not help. Would soaking it in water and then watering the plants with it help any? What about adding fish emulsion to the soaking water, or vinegar? Would these things help leach phosphorus out of the bone meal?

The fastest way to get phosphorous to plants is with phosphates, as in trisodium phosphate cleaners* or the phosphoric acid in Coca-Cola. Adding vinegar to the bone meal might help out, since the acid may help to free up some of the calcium phosphate in the bone:

Calcium phosphate + acetic acid ---> calcium acetate + phosphoric acid (soluble)

If you are going to do this, soak your steamed bone meal in the vinegar overnight first, as the reaction is slow to proceed.

But as long as your soil is fairly acidic, e.g., has lots of organic matter and humus in it, those humic acids will make the phosphorous in the bone meal available to the plants. Mycorrhizal fungi also do that, and they will even transport the phosphorous from where they find it to the plant root that is hungry for it.


*But this isn't a good idea, because the sodium part of the molecule isn't very plant-friendly.

So what is the chemical break down of steamed bone meal in vinegar.
If the calcium is dissolved into Ca+ and water where'd the phosphorous go???

David Crimmins wrote:So what is the chemical break down of steamed bone meal in vinegar.
If the calcium is dissolved into Ca+ and water where'd the phosphorous go???

My understanding is that calcium phosphate and calcium carbonate do not dissolve in water but they do dissolve in acid.

Calcium phosphate/carbonate are not polar, so we have to dissolve it with something not polar as well. Like likes like.

Labs like to utilize hydrochloric or nitric acids for the reaction, but that is kind of intense for what we are looking to do.

We are hoping to react with vinegar which is acetic acid.

Calcium Carbonate (Found in bones along with phosphates. Moreso found in egg shells)
CH3COOH + CaCO3 = Ca(CH3COO)2 + H2O + CO2
Acetic Acid + Calcium Carbonate = Calcium Acetate + Water + Carbon Dioxide

Calcium Acetate is water soluable and can utilized by plants

Tricalcium Phosphate (Common form found in bones)

Ca3(PO4)2 + CH3COOH = Ca(CH3COO)2 + H3PO4
Tricalcium Phosphate + Acetic Acid = Calcium Acetate + Phosphoric Acid

So to answer your question, the phosphorus forms into an acid that can be utilized by plants.

I hope this helps.

Fungi are the key here. Many soils have an abundance of P but it's in one or more insoluble guises and therefore does no good for the plants that need it. Fungi have the tools, such as the ability to secrete acids, that allow it to mine these sources and trade them for sugars in forms useful to plants.

Phil Stevens wrote:Fungi are the key here. Many soils have an abundance of P but it's in one or more insoluble guises and therefore does no good for the plants that need it. Fungi have the tools, such as the ability to secrete acids, that allow it to mine these sources and trade them for sugars in forms useful to plants.

This is great advice.  And sounds so much better than adding vinegar to the soil that might be acid.

It would be lovely to hear back from Gilbert to hear how this experiment from 2014 worked out.

Anne, I'd really like to hear back on that one too. Especially whether he had any luck with the fish emulsion, as many of my "regen" buddies in the area are getting great results with fish hydrolysate to stimulate fungal activity. Only takes a little bit....

I doubt vinegar would work anyway, you'd need a stronger acid. There's a rule saying that "the stronger acid liberates the weaker acid from its salt". I looked this up at some point, and if I got it right, acetic acid is weaker than phosphoric acid, which would mean it won't work. You'd need something stronger. Oxalic acid would work, I think, as would the three strong ones (sulphuric, hydrochloric and nitric). Oxalic acid has the added benefit that calcium oxalate is insoluble, and so will precipitate out of your solution. Anyhow, like you said, considering practicality and safety, fungi are probably the way to go (unless you necessarily want to mess around with acids...)

Phil Stevens wrote:... many of my "regen" buddies in the area are getting great results with fish hydrolysate to stimulate fungal activity...

What exactly is "fish hydrolysate" and is it home made or commercial?

Any ideas why it's working so well?

Jay, it's basically soup. The product is made by treating fish scraps in an enzyme solution until everything is liquid. I think there are high-temperature methods that are more akin to rendering but the commercial process is typically low-temperature.  It is some of the most unbelievably stinky stuff I've ever encountered and I reckon a simple rendering process, although probably very achievable on a small scale, is not anything you would want in the house...something to try on a day with the wind coming from the right direction, maybe. I have made fish bone broth and usually have the kitchen windows wide open for the duration.

My friend who traffics in the stuff (and has a 40-year practical background in organics and regen) thinks that the simpler carbohydrates that are left after the enzymes break down proteins are some of the very best fungal promotion agents and probably provoke a whole series of feedback effects when they get into the soil.

On the stench issue from the application side of things, this same friend went up in a helicopter to spray fish hydrolysate on some run-down hill country paddocks. He said the pilot gagged and nearly passed out from the smell. After I heard that story, I brought him a bag of biochar that had been soaked with the stuff. 24 hours later there was no detectable odor.

Fantastic. Thank you. BUT
if Phosphoric acid is water soluble and the Calcium Carbonate in Vinegar turns to Ca+ and Water, what are you left with? That is where I am still confused.? Not to pester I am genuinely curious as to what is going on w the Phosphorous? and what are the left over solids, that could be a whole other discussion..

post edit::
----------------------------------
I think I get it!
The solids are either not broken down yet or are calcium phosphate. My experiments seem to indicate that with a smaller amount of vinegar the Phosphorous reacts first to become phosphoric acid, a known agricultural pH reducer, and w the addition of more vinegar it has diluted to a mild tartness less intense and watery. It's some sort of a loop it seems. The Calcium will reattach to the Phosphorous to make calcium phosphate once again. So there must be a balance with the ratios of vinegar to bone meal to be able to create CA+ water and phosphoric acid to use as a soil conditioners, a double whammy in an impossible clay to help lower pH to be more manageable and allow more nutrient exchange for plant availability, but also flocculate and lift clay particles to help even more! Something the agriculture industry has obviously wanted to ignore it seems, but small organic farmers may find invaluable..

Phil Stevens wrote:On the stench issue from the application side of things, this same friend went up in a helicopter to spray fish hydrolysate on some run-down hill country paddocks. He said the pilot gagged and nearly passed out from the smell. After I heard that story, I brought him a bag of biochar that had been soaked with the stuff. 24 hours later there was no detectable odor.

Bingo!! (Bold in the quote is mine.) I get exactly the same effect when I soak biochar with my incredibly rancid weed teas, anaerobic and vile. And then suddenly ... smell? What smell?

This is an idea I was working on.  
A series of reactions to process phosphate.

First make ammonium carbonate.
6NH3 + 3CO2 + 3H2O →
3 (NH4)2CO3

Combine with gypsum to make ammonium sulfate.
3(NH4)2CO3 + 3CaSO4↓ →
3(NH4)2SO4 + 3CaCO3↓

React this with calcium phosphate. The resulting ammonium phosphate is water soluble and might be good as a foliar spray.
3(NH4)2SO4 + Ca3(PO4)2↓ → 2(NH4)3PO4 + 3CaSO4↓

Net:
6NH3 +3CO2 +3H2O + Ca3(PO4)2↓ → 3CaCO3↓ + 2(NH4)3PO4

——
Don’t want the soluble phosphate?  Redissolve the calcium from above.
3CaCO3↓ +3CO2 +3H2O → 3Ca(HCO3)2

Precipitate the phosphate into nanoparticles.  
3Ca(HCO3)2 + 2(NH4)3PO4 → Ca3(PO4)2↓ + 6NH4HCO3

6NH4HCO3 →
3(NH4)2CO3 +3CO2 +3H2O