If it were my land I would be tempted to load salt into my fertilizer spreader and take my tractor for a ride.
Lauren Southern has been doing a series of videos about South African farms. If they are not managed properly, they will become a dust bowl. It’s not inherently fertile land. It will turn to ruin without sabotage.
No need to salt the land. The dumb shits that take it over won’t know what to do and will destroy it anyway. If I was a Boer farmer, I’d leave and make arrangements to burn everything to the ground after I’m gone.