The article is devoted to devices for subsurface fertilization in the form of drip-air mixtures. A comparative analysis of spray mixers with centrifugal and jet nozzles has been carried out. The article presents the results of a study on the spray dependence on the ratio of air and liquid pressure with increasing fluid flow and steady air flow. It has been established that a spray mixer with a centrifugal nozzle gives a thinner spray cone is better in its operational qualities and will more fully meet the requirements for devices for intra-soil application of liquid fertilizers. In addition, it was determined that according to agrotechnical requirements, the average diameter of liquid droplets injected into the soil must be kept constant, and the flow rate must be changed, leaving the device speed and the compressor operating mode unchanged.