In analysing the performance of the working element of rotary motion consideration should be given to the
previously loosened soil. For such conditions, it was estimated, that the value of cohesion ‘‘c’’ was lower by 50%.
Another characteristic feature of working elements which rotate as well as move forward is the possibility of covering zones of soil disturbed by the previous tine (Fig. 3). For this purpose a correction coefficient was introduced; considering the ratio of covered zones to the total disturbed cross-section: