The oldest system of agriculture in Nigeria which now survives only in very remote areas is?

The oldest system of agriculture in Nigeria which now survives only in very remote areas is shifting cultivation, also known as slash-and-burn agriculture. Shifting cultivation is a traditional method of farming that involves clearing a patch of land, burning the vegetation, and planting crops. After a few years, the soil becomes depleted, and the farmer moves on to a new patch of land, leaving the previous plot to regenerate for several years before being used again. This system of agriculture has been used for centuries by indigenous people around the world and is still practiced in some remote areas where modern farming methods have not been adopted. Mixed farming involves growing crops and raising animals together, while marketing gardening involves growing crops for sale in local markets. Bush fallowing is a technique that is sometimes used in conjunction with shifting cultivation, where a patch of land is left fallow for an extended period to allow the vegetation to regenerate.