EN
In this study the possibility of complementing valves in a pneumatic single-seed drill is analyzed. Construction of a cup feed drill, with photo-cell controlled electromechanical power train, is shown. It was concluded that the principal problem in the complementing of valves is the synchronization of the path of grains sowed by the auxiliary seeder with the paths of the grains sowed by the main seeder. This synchronization is possible only for constant rotational speed of the seeding disk. In the case of improper synchronization of grain paths, the placament error for seeds seeded by the complementing seeder is so large that the complementing process becomes moot. The work also shows research methodology and describes equipment used.