It is a common practice to treat soil against pests and pathogens of agricultural crops to ensure its disinfection using alternative methods, which include electromagnetic radiation of various spectrums: ultraviolet (UV), infrared (IR), microwave (microwave), and high frequency (HF). The authors have developed an IR irradiator to disinfect soil mixtures placed in a thin layer on a conveyor belt. In order to optimize soil mixture disinfection with IR irradiation, the task was set to obtain regression equations of the irradiator operation modes. The authors studied different modes of the IR irradiation of soil mixture layer placed on the conveyor belt at the layer thickness of 10 to 50 mm, the IR irradiator hanger height of 50 to 250 mm, and the IR irradiator power of 9.5 to 47.5 W. The authors studied three main relationships describing the working process. 1. Dependency of soil mixture temperature on layer thickness at the constant IR irradiator power, constant height of the IR irradiator hanger, and constant speed of the conveyor belt. 2. Dependency of the travel speed of the conveyor belt on the hanger height of the IR irradiator at its constant power, constant soil mixture thickness, and fixed temperature range (T = 95±5°C). 3. Dependency of the conveyor belt travel speed on the IR irradiator power at a constant height of its hanger, constant soil mixture thickness, and fixed temperature range (T = 95±5°C). The obtained regression equations Obtained regression equations with an approximation accuracy of 0.976 to 0.999 can facilitate the calculation of the operating modes of various-size irradiators, optimizing the disinfection of soil mixtures with IR irradiation and integrate it with an automatic control system.