The Irony of Mehring's Obsessiveness
Mehring buys the farm and hires natives because he intends to pay them significantly lower than a fair wage and make a huge profit off the endeavor, but he is his own undoing because he's too neurotic to delegate. He spends all of his time personally supervising his employees because he doesn't trust them, but it's his fault for hiring people he regards so lowly. In the end, his farm is not nearly as profitable as he thought it would be initially because Mehring is wasting his time micromanaging his workers.
The Irony of Antonia's Departure
Antonia gives Mehring a chance at a solid relationship, but she asks him to make a few sacrifices in return. She needs him to be open-minded enough to accept her work as valuable and good, but he is unwilling to do so. She leaves, just like his ex-wife did, because she gives up on him. His stubbornness is too much to overcome, so he wastes his second chance.
The Irony of Terry's Departure
Terry ends up walking away from his wealthy inheritance because it compromises his values to accept it. Sympathizing with the anti-Apartheid movement, he does not want his father's money which has been earned by oppressing the native peoples. He too leaves because the money would be a curse to him instead of a blessing.
The Irony of Mehring's Gift
Mehring spends a little bit of money to treat his workers to some meat for Christmas. This is the first time he has extended generosity to his employees in any way, so it's a very important moment for all of them. Mehring proves that he really doesn't mean the gesture when he refuses to replace the slab of meat after a dog eats it. Even his generosity is insincere.
The Irony of Jacobus Burying the Corpse
As much as Mehring is disturbed by the improper burial of his employee who turned up dead, he does nothing to rectify the situation. He prefers to indulge his paranoia and to ignore the actual problem which is that a dead man has been disrespected. In the end, then, Jacobus buries the corpse with proper ceremony without Mehring's permission. All of a sudden peace is restored to the farm, but Mehring had no part in it all.
