Abstract: A slurry pump including a pressure tank with an inlet and a lower outlet and having a pneumatically operated, inwardly opening closure at the inlet and a hinged, outwardly opening door at the outlet swingable between opened and closed positions. An external source of air under pressure hydraulically shuts the closure and pressurizes the tank, forcing a semi-liquid slurry such as liquid manure contained within the tank through the outlet and into a duct leading to a lagoon or the like. A slurry level sensor shuts off the supply of air to the tank when the slurry reaches a given level in the tank.