# Soil pH and locking mechanism of nutrients (metals)



## Babameca (Jul 29, 2019)

Hi,
Being a lawn obsessed, I am reading a lot in this forum and also other sources to get more knowledgeable. My background (chemical engineer) is pushing me to look not only for answers, but the (bio)chemical reasoning behind.
I may be completely off track here, but am expecting some feedback on my analysis.
pH in general applies to solutions (liquid form) and demonstrate the absolute count of H+ and OH- ions suspended in a solution. Water has a pH of 7 (neutral) because chemically has an equal amount of H+ and OH- ions. Any disbalance of this will lead to a lower/higher pH. All metals in suspension are loosing electrons to form positive ions. If OH- is predominant (higher pH) in your soil (suspension) then those metal ions will be attracted and 'locked'. If pH is lower than 7 then H+ will dominate and metal ions will be 'free' and accessible by the roots.
Here it is.
Thoughts?
M


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## troksd (Jul 27, 2018)

Water applied to lawn is almost never neutral. Even rain leans more toward the acidic (at least around my neck of the woods). Metals are locked and not readily available to plants. One would use liquid / chelated metals as a work around.

P.S.
I suck at chem


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## Babameca (Jul 29, 2019)

@troksd I was referring to water as a molecule, not drinking or rain water. Thanks for the comment.


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## ABC123 (Jul 14, 2017)

If your looking to drop ph you can apply elemental sulfur if irrigation is a higher ph than desired if that's what your referring to.


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## g-man (Jun 15, 2017)

@gergelybg I moved this to the soil folder.

I'm not sure if you have a question. Yes the pH matters in availability to move from soil to roots.


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## Babameca (Jul 29, 2019)

@g-man No, It was not a question, but thinking out loud...


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## Dawgvet (Jul 2, 2019)

gergelybg said:


> Hi,
> Being a lawn obsessed, I am reading a lot in this forum and also other sources to get more knowledgeable. My background (chemical engineer) is pushing me to look not only for answers, but the (bio)chemical reasoning behind.
> I may be completely off track here, but am expecting some feedback on my analysis.
> pH in general applies to solutions (liquid form) and demonstrate the absolute count of H+ and OH- ions suspended in a solution. Water has a pH of 7 (neutral) because chemically has an equal amount of H+ and OH- ions. Any disbalance of this will lead to a lower/higher pH. All metals in suspension are loosing electrons to form positive ions. If OH- is predominant (higher pH) in your soil (suspension) then those metal ions will be attracted and 'locked'. If pH is lower than 7 then H+ will dominate and metal ions will be 'free' and accessible by the roots.
> ...


Your premise is correct. However, I see two minor flaws. 
1 - You are trying to apply a controlled *chemical study*(neutral pH water) and apply it to an uncontrolled *biological* environment. 
2 - You HAVE to take the mineral composition of soil into account (as buffering agents, etc). Geochemistry plays an important role in soil pH, and because of this, you cannot leave out a soil's CEC out of consideration.

Also, there are way too many variables in each individual biological subject. Some plant's root systems will not do well in acidic soils; therefore, will not absorb metals no matter how available they are.

A little light reading for Enquiring minds. WARNING: Long boring research paper 
PS: My background is not chemistry. Mainly Zoology/Biology/Veterinary Medicine


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## Babameca (Jul 29, 2019)

@Dawgvet Thanks a lot!


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