Adding gypsum to the biochar burn beforehand

I just saw a post by a guy on another forum.  Sounds interesting. My main problem with it is that I have no way currently to measure the heat of my biochar, so as in the case with ferrous sulphate, I don't know if I am improving the quality of the biochar or decreasing it.

"If you mix 30% gypsum with your biomass and then pyrolyse at about 450C and add to you holes you will find that this works more effectively at both improving soil and increasing yield.  Very synergistic.  If you also add rock phosphate to the gypsum biomass (grasses are usually the best biomass to use) then you will have higher abundance of fungi."
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John S
PDX OR

Anhydrite is commonly added to soils to increase calcium apparently, and is better because it has a higher concentration of it than the hydrated gypsum does per pound. But once it gets wet in the soil, it just becomes gypsum if I understand it correctly. So I'm not seeing a benefit to burn it in biochar, unless some other chemical reaction is taking place to make something different.

https://mineralexpert.org/article/anhydrite-mineral-calcium-sulfate#:~:text=In%20agriculture%2C%20anhydrite%20is%20a%20valuable%20source%20of,Typical%20folded%20anhydrite%20from%20Bochnia%20salt%20mine%2C%20Poland.

Very informative article. My science background is not quite enough to really understand it, but I feel like I get 1% smarter each time I TRY to read it. So if I try to read it 50 times...............
John S
PDX OR