The furrow depth in the corn furrow drilling is directly connected with the working depth of the furrower hoe, their evenness being determinative for the stability of the drill ploughshare depth. The main factors which influence the furrower movement stability are the field microrelief, the soil condition, the tillage mode and their design parameters. The effect of first two factors on the hoe of the furrower is of a random character and is determined as the sum of dispersions of each variable at the output of the dynamic unit. A transfer function has been determined on the basis of the obtained mathematical model. It reproduces fluctuations of angle ψ as the fluctuations of the tillage depth and represents a conservative link. The obtained transfer function allowed to calculate the amplitude-frequency characteristics of the dynamic system. The analysis of the theoretical amplitude-frequency characteristics showed that an elastic articulated joint of the cultivator hoe with the furrower in the form of wing flaps or blades connected to the frame of the row-crop drill results in increased amplitude fluctuation in a transversely-vertical plane. It has been established that this occurs within a frequency range from 1.3 to 1.6 Hz representing the field microrelief fluctuations, yet they do not belong to the range of resonance oscillations. It has been proved that significant decrease in the fluctuations of the furrower is possible after its equipment with a spring of high deflection rate. Under real conditions the elastic articulated joint of a combined working tool with a row-crop drill frame practically corresponds to the rigid one with more than 20 kN m-1 deflection rate.