[jamescrowley]

It can actually have benefits to the soil as a fertiliser - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10011191/

[huytersd]

Anything bigger than a pebble is going to ruin harvesters and planters.

[ksenzee]

They’re using rock crushed to ~100 microns.

[lucb1e]

The person you're replying to posted a link which mentions in the "materials and methods" section that the particles in the study were all smaller than 2mm (and 99.6% smaller than 1mm).

To compare with your pebble, which wikipedia says is

> A pebble is a clast of rock with a particle size of 4-64 mm