Abstract: Embodiments include a gasification process where the carbon content of the residue from gasification of agricultural waste products and the fly ash content of the gaseous exhaust is controlled by regulated inflow of gasification-supporting air in a plurality of flow stream at different velocities to enhance fluidization of particulate feed in a bed being raked by a rotating sweep arm inducing radially outward movement of gasification residue into a collecting zone from which the residue enters a discharge duct. The particulate feed is dropped at a location in the gasification chamber above the bed in alignment with the inflow stream of maximum velocity.