How does Prince Charles earn an income from the Duchy of Cornwall?

I’ve read his site but I’m still confused. Is it a semi-feudal thing where vassals kick up a portion of their income to him? Does he just collect rent? Does he own the farms (the land itself I understand is in trust) and have to deal with labour issues? I don’t ever recall reading of any protests or uprisings over HRH’s heavy handed treatment of the villans yet the Windsors are notorious tightwads so there must be some reason why they keep quiet. The gibbet?

He owns land, and earns money from various ventures including organic farming and through renting out property. It should be noted that he voluntarily pays tax on earnings @40%. His farms operate in the same manner as any other farm in that he employs staff to run them.

I’m told his biscuits (sold under the ‘Duchy Original’ brand) are quite good.

According to wikipedia Charles actually holds 135,000 acres spread across Devon, Cornwall, Herefordshire and Somerset. The land is passed down to each Heir Apparent, so he couldn’t just decide to sell it on a whim.

There’s a feature story on Chares and the Duchy in this month’s National Geographic.