The article shows the effect of compacted soil lump which forms on the blade and in front of it on the characteristics of performance and lifetime of soil cutting working organs. Facts proving the presence of compacted soil lump on the blade in process of cutting soil layer are given. The results of theoretical and experimental researches are brought, allowing to obtain the design parameters and to improve the technical level of working organs used in soil cultivating and cutting. Negative factors that affect the efficiency of parts of tillage equipment in the conditions of compacted soil lump effect are substantiated and listed. The cyclical nature of its formation on the blade cutting the soil layer is noted. The article presents a hypothetical scheme of soil lump effect on the blade of working organ with different degrees of bluntness. This scheme explains the physical meaning of negative effects that are associated with deterioration of energy and agronomic indicators of parts and equipment during the operating wear in conditions of clear-cut compacted soil lump (on relatively strong soils). The article determines the fundamental reasons for the sharp increase in resistance of soil in the presence of chamfered edge on the blade of cutting working organ, which is associated with movement of compacted soil lump under the blade. Regularities defining the values of specific loads acting on the blade are given. The differences in variation of total and specific loads on working organ under formation of compacted soil lump are noted. The article substantiates a special role of the rear face of the blade of working organ in connection with heavy conditions of loading of soil layer under it. It describes the practical design and technological methods of protection of parts against the effects of compacted soil lump. Substantiated values of the parameters of working organs of agricultural machines interacting with soil are given, that provide the increase in their operational, agronomic and life characteristics.