Okonkwo was a wealthy man because he was a great farmer. One crop that was HUGE for the igbo people were yams. Yams are grown to gain wealth and also to feed one’s family. They are a symbol of masculinity and ability as a provider.
The best way to bake sweet potatoes/yams is to lightly coat them in [olive oil] or coconut oil, pierce ‘em multiple times with a knife, and stick them in a oven for 45 minutes to an hour. From Nom Nom Paleo