The present invention is directed to an applicator having an agricultural product mechanical conveying system which transfers particulate material metered into the mechanical conveying system from one or more source containers to the application equipment on demand, and meters the material at the application equipment. The mechanical conveying system employs longitudinal mechanical distributors that operate to move and mix the particulate material from one of the source containers or tanks along the mechanical distributor to a plenum. At the plenum the different types of particulate materials are further blended, such as within a particle injector, and delivered to the distribution nozzles for discharge from the applicator.