Control and command system for agricultural machines, in which an agricultural machine has - a supporting frame; a series of tools adapted for shredding the ground in depth; - a roller, to which is connected said series of tools, said roller being provided with spikes; - a sensor, able to measure, in a first initial condition according to which said agricultural machine rests on a fixed horizontal reference plane, a height difference, with respect to said fixed reference plane in which in said first initial reference condition, said agricultural machine is in horizontal position on a rigid plane with the outermost circumference (C, C1) of the roller of the machine in contact with said rigid plane and the tools of the agricultural machine placed beyond said rigid plane; - at least a means for storing what is measured by said sensor, so as to obtain an instantaneous depth measurement of the tools beyond the fixed reference plane, characterized in comprising: - a first support fixed to said frame of the agricultural machine from which is calculated a first horizontal level with respect to said fixed reference plane - and a second support fixed to said roller from which is calculated a second horizontal level with respect to said fixed reference plane, said height difference being measured between said first horizontal level and said second horizontal level, said sensor being configured to measure instantaneous differences of said height difference at successive times with respect to said initial condition and said control system being also able, through said at least a means for storing, by using a software application, to store said height differences and to measure said instantaneous height differences, as well as to store a predefined value relative to a sinking measure is equal to a difference in height between a maximum height of at least one of said spikes of said roller beyond said fixed reference plane. - a supporting frame; a series of tools adapted for shredding the ground in depth; - a roller, to which is connected said series of tools, said roller being provided with spikes; - a sensor, able to measure, in a first initial condition according to which said agricultural machine rests on a fixed horizontal reference plane, a height difference, with respect to said fixed reference plane in which in said first initial reference condition, said agricultural machine is in horizontal position on a rigid plane with the outermost circumference (C, C1) of the roller of the machine in contact with said rigid plane and the tools of the agricultural machine placed beyond said rigid plane; which said agricultural machine rests on a fixed horizontal reference plane, a height difference, with respect to said fixed reference plane in which in said first initial reference condition, said agricultural machine is in horizontal position on a rigid plane with the outermost circumference (C, C1) of the roller of the machine in contact with said rigid plane and the tools of the agricultural machine placed beyond said rigid plane; - at least a means for storing what is measured by said sensor, so as to obtain an instantaneous depth measurement of the tools beyond the fixed reference plane, - a first support fixed to said frame of the agricultural machine from which is calculated a first horizontal level with respect to said fixed reference plane - and a second support fixed to said roller from which is calculated a second horizontal level with respect to said fixed reference plane, said height difference being measured between said first horizontal level and said second horizontal level,