The effect of microfertilizer «Agro-Master» on the yield and quality of early and medium early of potato tubers varieties was studied, carried out at the experimental field of North Caucasus Research Institute of Mountain and Foothill Agriculture - branch of the VSC of RAS in the forest-steppe zone of Republic of North Ossetia-Alania on grass rotation in the period from 2017 to 2019 yy. The experimental data indicate that the use of microfertilizer «Agro-Master» in a specific soil and climate zone is a promising technique that can improve the productivity and quality of potato tubers in the field. The data of our studies on leached chernozems showed no clear differences in the timing of the onset of the development phases of potatoes. The intensity and speed of emergence of seedlings to a greater extent depends on weather conditions and varietal characteristics. It was found that when spraying potatoes with microfertilizer «Agro-Master» in different doses, the process of dying of tops is slowed down in comparison with the control options. So, in the Zukofsky early variety, the top-off phase begins 7-8 days earlier than the Red Scarlett variety and 10-11 days of the Predgorny variety of local selection. The maximum yield increase was observed when processing of the microfertilizer «Agro-Master» at a dose of 2 kg/he on the pre-mountain local breeding grade – 27,5 tons per hectare, while the increase in yield to control was 5,0 tons per hectare, for varieties of Zukofsky early and Red Scarlett – 5,0 and 4,7 tons per hectare respectively. The highest dry matter content was on the experimental version (dose 2 kg / ha) for the Predgorny variety – 26,6 %, the Zukofsky early and Red Scarlett varieties – 25,9 and 23,8 %, that accordingly is more than control on 3; 2 and 3 %. The starch content in the studied potato tubers in the experimental varieties was diverse. The maximum starch content in potato tubers was obtained using the variant treated with Agro-Master at a dose of 2 kg/he for Predgorny variety (16,0 %), which is explained by the favorable influence of microfertilizer «Agro-Master» and the manifestation of varietal characteristics.