Abstract: A method and apparatus for dispensing a substance such as a hydrophylic polymer into a soil to minimize the need for repeated irrigation, plant feeding or the like. A trailer supports a mixing tank within which the polymer and a liquid such as water are continuously agitated. The mixture, in a liquid form, is sent through a pump to an outlet having a plurality of apertures communicating with the tank via a manifold. A valve operatively conditions the throughput of the water and polymer so that a series of high pressure pulses exit the outlet and cause slugs of liquid to contact the ground at a sufficient velocity that the slugs penetrate the soil and deform under the surface of the soil. The rapid opening and closing of the valve when used with the outlet's apertures can provide a distribution pattern in the soil which is substantially uniform and minimizes the likelihood of disproportionate polymer infusion in the ground which would otherwise cause non-uniformly swelling.