Gypsum

[Bowsnbucks]

Without pouring over hundreds of threads - or starting arguments that I think happened here before about it -

What does gypsum do for soil health? Never researched it specifically.

 

[SD51555]

Must this fall on me? Ok, I'll bite.

Adds calcium - calcium is the number one missing nutrient when weeds are a major problem
Adds oxygen (pore space)
Reduces severity of soil crusting
Enables better water infiltration

Adds sulfate sulfur, and that should be it's own thread.

Sulfate - flavor nutrient for forages. Deer will select sulfate rich crops vs an identical crop deficient in sulfate
Sulfate - binds to magnesium to form espom salts and helps reduce excess magnesium
Sulfate - enhances nitrogen use efficiency in crops. Higher yields with lower rates of N.

 

[jsasker007]

Much different than lime?

 

[Bowsnbucks]

I thought anything sulfur was acidic. No??? The only thing I ever heard about gypsum was that it was good to loosen clay soils.
How do you tell if your soil needs gypsum?? Is there a test for it??

 

[SD51555]

Much different than lime?

It is.

You don't get any sulfate with lime.
Gypsum won't change your pH any noticeable amount.
Gypsum is a good way to add calcium without moving your pH if you're trying to cure other non-pH issues with calcium (weeds, crusting, oxygen, compaction etc)

 

[Telemark]

I go on the Norwegian equivalent of Craigslist to find people who are trying to get rid of leftover drywall. I smash the drywall into pieces and scatter it around my marginal soils. I can't prove it works, but it sure seems to help.

 

[Hoytvectrix]

The only thing I would add to the above is that it can do those things, not that it necessarily will do those things. Some soils will benefit from gypsum more than others. Sodic (high sodium) and heavy clay soils are going to be the ones that benefit the most from gypsum. Studies measuring the effect of gypsum have mostly been done in sodic soils, so it's value is sometimes overstated for Midwestern soils (which are by far and large not sodic). Sodic soils have a very high pH (>8.5). Saline and saline-sodic soils have similar soil structure issues, but may not necessarily benefit from gypsum.

 

[SD51555]

The only thing I would add to the above is that it can do those things, not that it necessarily will do those things. Some soils will benefit from gypsum more than others. Sodic (high sodium) and heavy clay soils are going to be the ones that benefit the most from gypsum. Studies measuring the effect of gypsum have mostly been done in sodic soils, so it's value is sometimes overstated for Midwestern soils (which are by far and large not sodic). Sodic soils have a very high pH (>8.5). Saline and saline-sodic soils have similar soil structure issues, but may not necessarily benefit from gypsum.

Whole heartedly agree. I can't express enough the need to soil sample with your eyes and hands and shovels. I often encourage people to try a 40 pound bag on a 10x10 yard spot and watch what happens. If it doesn't turn greener or show a browse preference, or whatever desired improvement you're looking for, it's probably not a value add.

But if you're stricken with crusting, low calcium weeds, pasty clay, poor water infiltration, or need a kick to make the plot taste better, throw down a $10 bill at Menards and try a bag. If you don't see a difference, don't go all in.