Abstract: A closed agricultural chemical batching, measuring and mixing system is disclosed for mounting to a sprayer tending truck. The system includes a measuring tank on which a partial vacuum is drawn by opening a connection to the intake manifold of the internal combustion engine of the truck. The measuring tank is in turn communicated to at least one manifold having numerous valve control inlets, all communicated to discrete agricultural chemical containers which can include highly toxic liquid chemicals. At the inlet remote from the mixing tank, the manifold communicates to a supply of surfactant. Preselected amounts of the liquid chemicals are sequentially drawn by the partial vacuum through the valve controlled manifold and to the measuring tank in which they are accumulated. The surfactant is then drawn through the manifold and into the measuring tank to flush the system.