[millzlane]

I think it's the fact that it was applied to a field.

"A team of researchers from the universities of Zurich and Basel, Agroscope, and the Research Institute of Organic Agriculture (FiBL) has now shown for the first time on a large scale that applying mycorrhizal fungi in the field works. The fungi were mixed into the soil before sowing crops on 800 trial plots at 54 maize farms in northern and eastern Switzerland."

[randomdata]

The regional maize yield record produced for a growing contests is only 25% higher than we can see from general production without meticulous care for the sake of a contest. Hard to fathom that this is moving the needle by 40%.

[RetroTechie]

Article doesn't state yield w/ respect to best-yielding fields. But up to 40% higher yields on fields that had a good deal of pathogen fungi in the soil ("unhealthy" soils, if you will).

So this is not upping yields 40% across the board. More about bringing poorer-performing fields up to the level of better-performing ones.

Personally I think a well-managed field wouldn't need this type of inoculation, as it would have the beneficial fungi in its soil already (and these research findings seem to indicate this). The #1 thing there would be to disturb that soil as little as possible (like, no-till farming).

For less-well managed fields, this might be a quick 'n dirty fix to undo some of the shortcomings in a field's condition.