A control and command system for agricultural machines, wherein the agricultural machine has a supporting frame (14), a series of tools (10) adapted for shredding the ground in depth, which are connected to a roller (11), said roller (11) being smooth or provided with spikes (16), and a refining or leveling bar (15), configured to hold the ground inside a machine working chamber to increase the refinement of the worked soil, said bar (15) being fixed parallel to the roller (11) and being adjustable in height with respect to a surface level of the ground (T)； a load detectable by one or more load cells (CC), which are placed between the refining bar (15) and a series of supports, is positioned on said refining bar (15). The load changes on the basis of the type of the soil to be worked.
