i work with farmers. glyphosate enters plants through the stomata on their leaves and slides down tubules to their roots where it blocks water absorption. once it touches the ground, it is quickly neutralized by the bacteria in soil. residue is easily washed off with a rinse the problem is heavily subsidized american farmers are lazy as fuck and will blanket spray crops with it even when not needed and on heavily quantities. they also don't even bother trying to avoid spraying into canals and ponds (where the glysophate will not degrade as it does in soil). there's also some much worse herbicides that see common use, such as 2, 4-d that no one talks about because the media hasn't told em about it like spooky scary roundup.
Canada