Jeßus wrote:
As per the subject...

I have about an acre of 'lawn' that has become heavily infested with
dandelion and plantain. This spring I intend ploughing the lot up and
replanting with pasture grasses (who needs an acre of lawn?).

Problem is, I want to do it organically... and I'm out of practical
ideas on how to do this. Any ideas, anyone? Cheers.

Take a hoe/rotary tiller and chip the crown out of the plant.
If you dont know what the crown is, think of the bit on a carrot where
the leaves grow from. If you can slice that bit off the root, then the
plant dies.

Alternatively, you slash when 50% of the plant are in flower, before it
sets seed. eventually, after a number of years(decades), it will die out
as the seed bank is exhausted.

What are you going to graze on the pasture and do they eat plantain and
dandelion? Aka, why worry about it, just plant your pasture species.