This kind of thing often has issues with the emissions associated with mining the rock, crushing it, and transporting it to fields ends up emitting more than gets removed from the atmosphere. They talk about measuring rock behavior in fields…but not doing a full accounting of what was involved in getting it there.

They don’t mention anything besides this effect. I was sorta hoping it would help with erosion and water retention of the soil to.

This has to have other effects.

How available is that carbon to microbes, are they missing out on their own source of carbon?

What other minerals are in the volcanic ash that will potentially mess with the complex balance of minerals in the soil.

How much green house gas is made in the mining and proccessing of this volcanic ash.

Sounds to me like some ones land near a volcano got errupted on and they are trying to find a way to make money from it.