Gypsum anyone?

Rasta Roy

Rasta Roy

Well-Known Member
Tupapa said:
Not saying here that supersoil will increase availability., My point is that yes of course is water soluble, but minimal like 3%., but in order for the plant to uptake it it needs time to ''cook" ., Not like you apply your gypsum today and tomorrow the plant will be already uptaking it.
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Gypsum doesn't become more available by composting (aka"cooking). It becomes available Everytime water is applied to it. It dissolves through weathering, releasing calcium and sulfur into the soil along the way.

We get that gypsum isn't liquid calcium...But you're literally arguing with an agricultural textbook.

"Gypsum has calcium sulphate in the dihydrate form (two water molecules with each calcium sulphate) making it somewhat more soluble than the anhydrous form of calcium sulphate. A small amount of gypsum can dissolve at once in the soil solution (limit is 0.24 g per 100 mL of water at 20oC). Once the soil solution reaches the limit of calcium sulphate in solution, gypsum starts to precipitate again. Thus there is a fast provision of calcium and sulphate into soil solution for plant uptake or effect on the soil but the overall rate of release from gypsum is controlled by the rate with which the calcium and sulphate are taken or move from the soil solution.

As gypsum dissolves, one sulphate ion is released with each calcium ion. Since a sulphur atom is lighter than a calcium atom, the amount of sulphur released is around 75% of the amount of calcium by weight.

Calcium sulphate is much more soluble than calcium carbonate (lime) and over time will release calcium at a significantly faster rate than the weathering of lime. Time of release is variable depending on soil conditions including moisture level (dryer is slower), drainage (fastersoil water velocity means more ability for the gypsum to dissolve as calcium moves downwards), soluble salt level (higher levels of some salts can make it slower), sodium level (higher sodium level makes it faster as the calcium goes on to the exchange sites allowing more gypsum to dissolve) and the general ability for the soil (and plants) to “absorb” calcium and sulphate from the soil solution."
 
Dr. Who

Dr. Who

Well-Known Member
NaturalFarmer said:
I was thinking of the Chinese wallboard off gassing problems from a few years ago and thinking the same but worth looking into more I guess.
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Gets used a lot (wallboard) by orchards and tomato farms around me. Now the gypsum mine/board factory is closed and that has changed.....their source dried up..

I use only garden gypsum to build soils.....very different in concentrations and has no un-natural binders......Wall board is FAR from organic in many ways!
 
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ttystikk

ttystikk

Well-Known Member
Rasta Roy said:
Gypsum doesn't become more available by composting (aka"cooking). It becomes available Everytime water is applied to it. It dissolves through weathering, releasing calcium and sulfur into the soil along the way.

We get that gypsum isn't liquid calcium...But you're literally arguing with an agricultural textbook.

"Gypsum has calcium sulphate in the dihydrate form (two water molecules with each calcium sulphate) making it somewhat more soluble than the anhydrous form of calcium sulphate. A small amount of gypsum can dissolve at once in the soil solution (limit is 0.24 g per 100 mL of water at 20oC). Once the soil solution reaches the limit of calcium sulphate in solution, gypsum starts to precipitate again. Thus there is a fast provision of calcium and sulphate into soil solution for plant uptake or effect on the soil but the overall rate of release from gypsum is controlled by the rate with which the calcium and sulphate are taken or move from the soil solution.

As gypsum dissolves, one sulphate ion is released with each calcium ion. Since a sulphur atom is lighter than a calcium atom, the amount of sulphur released is around 75% of the amount of calcium by weight.

Calcium sulphate is much more soluble than calcium carbonate (lime) and over time will release calcium at a significantly faster rate than the weathering of lime. Time of release is variable depending on soil conditions including moisture level (dryer is slower), drainage (fastersoil water velocity means more ability for the gypsum to dissolve as calcium moves downwards), soluble salt level (higher levels of some salts can make it slower), sodium level (higher sodium level makes it faster as the calcium goes on to the exchange sites allowing more gypsum to dissolve) and the general ability for the soil (and plants) to “absorb” calcium and sulphate from the soil solution."
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This is exactly what I mean when I say that nutrients act differently in soil than they do in a fully soluble hydroponic mix. This is counterintuitive to me, but then I've never done any organic style grows.
 
NaturalFarmer

NaturalFarmer

Well-Known Member
ttystikk said:
I don't recall ever getting sarcastic with you.
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I get tired of telling people the same thing over and over and over and over when I provide a plentiful amount of information based on science for you to see for yourself. Not trying to be a prick, but it pisses me off when people who don't understand the science or what they are talking about, act like they need to teach the class.
 
NaturalFarmer

NaturalFarmer

Well-Known Member
If you want solubility and you don't care about organic. Go get gypsum from flue gas or use expensive Calcium Nitrate but understand that salinity will be an issue. This thread is about gypsum for organic SOIL.
 
NaturalFarmer

NaturalFarmer

Well-Known Member
ttystikk said:
This is incorrect. Plants can only uptake nutrients in their soluble form.
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Forms of Essential Elements Taken up by Plants

Element Abbreviation Form absorbed
Nitrogen N NH4+ (ammonium) and NO3- (nitrate)
Phosphorus P H2PO4- and HPO4-2 (orthophosphate)
Potassium K K+
Sulfur S SO4-2(sulfate)
Calcium Ca Ca+2
Magnesium Mg Mg+2
Iron Fe Fe+2 (ferrous) and Fe+3 (ferric)
Zinc Zn Zn+2
Manganese Mn Mn+2
Molybdenum Mo MoO4-2 (molybdate)
Copper Cu Cu+2
Boron B H3BO3 (boric acid) and H2BO3- (borate)
 
NaturalFarmer

NaturalFarmer

Well-Known Member
"Gypsum is a good choice for Ca addition because it is inexpensive, non-toxic, and safe to handle, and it is relatively soluble. We are interested both in solubility (how much of the salt will dissolve in the soil water) and the rate of dissolution (how fast the salt dissolves in water). Mined gypsum is wellcrystallized, having formed over millions of years. Waste gypsum, on the other hand, is formed rapidly during industrial processes, and is less crystallized. Although they have the same chemical formula, the waste gypsum materials dissolve more rapidly than mined gypsum."

http://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1413.pdf
 
ttystikk

ttystikk

Well-Known Member
NaturalFarmer said:
I get tired of telling people the same thing over and over and over and over when I provide a plentiful amount of information based on science for you to see for yourself. Not trying to be a prick, but it pisses me off when people who don't understand the science or what they are talking about, act like they need to teach the class.
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...none of which describes me. I DID bring textbook knowledge to this discussion in an attempt to understand the whole picture.

If you can't handle questions from people who know a lot about the subject, maybe it isn't everyone else's thinking that's flawed?

Now, I've repeatedly said that it's apparent that gypsum works differently in soil than in the water column. What I haven't gotten from you is any discussion about WHY.

...Nevermind HOW to use this knowhow effectively, other than a few personal anecdotes.

If you want sarcasm, I can dish it with the best. I generally prefer to keep it in the politics section, however.
 
NaturalFarmer

NaturalFarmer

Well-Known Member
NaturalFarmer said:
I get tired of telling people the same thing over and over and over and over when I provide a plentiful amount of information based on science for you to see for yourself. Not trying to be a prick, but it pisses me off when people who don't understand the science or what they are talking about, act like they need to teach the class.
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I stand by what I said.
 
NaturalFarmer

NaturalFarmer

Well-Known Member
ttystikk said:
Now, I've repeatedly said that it's apparent that gypsum works differently in soil than in the water column. What I haven't gotten from you is any discussion about WHY.
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Here is your answer.
"The solubility constant of gypsum is 2.4 x 10-5. That means if you have solid gypsum in equilibrium with water, the concentration of Ca (in moles per liter) times the concentration of SO4 (in moles per liter) equals 2.4 x 10-5. If it's less, the gypsum will dissolve."

https://www.uwgb.edu/dutchs/Petrology/SolConst.htm
 
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