In this paper, a few assessments of the optimal parametric combinations in the operating regime of agricultural aggregates with ploughs of variable width are made. The starting point was from a classic expression of the tillage draft force required for traction. In order to find optimal points, some problems of constrained extreme have been formulated. Extremes provided by the optimal working width and speed have been found. Such optimal points have existed in the literature, for about half a century. Using these theoretical estimates of the optimal points sought, assessments of the possibilities for their experimental validation were made. Basic conditions for an experimental plan are formulated to highlight such optimal points.

The paper presents theoretical research conducted for the optimization of the working process of variable width ploughs. Thus, were determined multivariable regression functions for the traction force of the plough with variable working function of the control parameters: working depth, working width and working speed. The use of these theoretical considerations of the optimal points sought lead to the opportunity of making assessments on the possibilities to conduct their experimental validation. Conditions for an experimental plan were formulated to highlight such optimal points and the theoretical results were validated through experiments.