Speaking on a trip to Romania, the heir to the throne said smallholders were "crucial" to the future of food security.
"I happen to think the small farmer, the smallholder, is absolutely crucial to the maintenance of food security," he said.
"It can't all be done by gigantic corporations, agribusinesses. Some of them try, but a lot of them are not interested in biodiversity or culture or rural communities.
In an interview for BBC's 'On Your Farm' programme, Charles urged a revival of traditional farming methods.
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Charles, who is vocal on environmental issues, warned that a global warming could have serious implications on food production, and leave humankind "totally vulnerable".
He was in Transylvania to set up a scheme to help rural communities. He has been a regular visitor to the region since 1998, and owns two holiday houses there which he rents to tourists.
"That's entirely why I'm trying to do all this, is that I mind about the future for your grandchildren as well as mine and lots of other people's," he said.
He has launched a village cooperative in Transylvania, that will aim to teach craft skills and encourage people to market their home-grown and handmade products.