Why were the peoples of the Kongo able to produce food surpluses?

The peoples of the Kongo were able to produce food surpluses due to their advanced agricultural practices, which included the use of crop rotation and the cultivation of diverse crops like yams, cassava, and rice. The region's fertile soil and favorable climate also contributed to high agricultural productivity. Additionally, the establishment of trade networks allowed for the exchange of goods and resources, further enhancing food security and surplus production.