The aim of this work is to develop a numerical application to determine the materials characteristics and to simulate the phenomena of cutting process by a single stalks and a few stalks as well as to present the possibilities of its application for simulation of the cutting process under real conditions - occurring in cutting assemblies of typical agricultural machinery. An example of use of this application to the modelling of cutting process of stalks in the cutting system of the harvester Bizon is presented. The next stage will be to develop a methodology to enable better design of the knife units used in a variety of agricultural and forestry machinery and their optimization.