Rice and barley were detected by the plant opal phytolith analysis of the soil of remains and the clay of the earthenware in the Kumamoto Prefecture, by the pollen analysis of remains in Fukuoka Prefecture in the end and the last periods, and at the remains in the Kumamoto City; rice was detected at the remains in Oita Prefecture.
熊本県下の遺跡の土壌と土器胎土のプラント・オパール分析、福岡県下の後・晩期遺跡の花粉分析、熊本市の遺跡でイネ、オオムギ、大分県遺跡でイネなどが検出されている。