The scientific problem of this study is the justification of the expediency of combining the technological operations of sowing cereals and applying the main and starting doses of mineral fertilizers when using a combined machine and tractor unit (aggregate). During the research there were used methods of conducting field experiments using standard equipment. During the planned experiments there were used correlation methods and methods of numerical calculations on a PC. The comparative studies of the quality of barley sowing with basic and modernized fertilizer-sowing units showed the following values of qualitative indicators. So, the coefficient of seed depth variation of the base unit was – 8.2%, and the combined (modernized) unit – 4.7%; The uniformity of seed distribution along the length of the line for the basic unit is – 63.8%, for the modernized unit – 84.9%; Field germination of seeds when sowing the basic unit is 80.4%, modernized – 87.4%. Thus, when using the combined fertilizer-seeding unit, the uniformity of seed distribution along the length of the string will be substantially increased. At the same time, the field germination of seeds will increase, and the coefficient of variation in the depth of seed placement in the furrow will decrease. Based on the results of field experimental studies, an increase in the yield of spring wheat and barley was found in the application of a combined fertilizer-seed aggregate with the simultaneous introduction of a basic fertilizer-seeded fertilizer into the soil and sowing of cereals with the application of a starting dose of mineral fertilizer in comparison with the known schemes of such operations. The obtained results confirm the expediency of combining these technological operations with one pass of the combined machine-tractor unit (aggregate).