Abstract: The present invention represents an improvement in state of the art apparatus for injecting controlled amounts of a soil amendment, including fertilizers, into an irrigation system, by first effecting the batch mixing of a selected soil amendment, in the form of a particulate material in a fluid medium, such that the particulate material is either dissolved or suspended in the fluid medium to form a slurry, continuously locating an area within the mixing tank in which the admixture displays the greatest, or optimum homogeneity, and continuously withdrawing metered amounts of the resultant slurry for injection into an irrigation system over the entire period of the irrigation cycle.