A model for determining the operating costs of machine-tractor units for sowing, taking into account the duration of work and the size of the area

Abstract

The article presents an analysis of the impact of the performance of machine-tractor units on the duration of technological work in crop production. The results of a survey among specialists of agricultural organizations of the Tomsk region, indicating a significant influence of the technical factor in general on the productivity of machinery (33,9 %), are presented. An interpretation of the survey results is given and, based on these data, a rationale is formulated to create a methodology for optimizing the technological parameters of sowing units. The aim of the work is to develop a methodology for optimizing the technological parameters of sowing units, compiled on the basis of different models of tractors by the criterion of minimum operating costs. The scientific novelty is the introduction of the indicator «unit operating costs of the sowing unit», which explains the choice of a tractor of a certain traction class taking into account the used sowing machines. As a result of the calculations, the fact of a nonlinear dependence of the productivity of the sowing units on the installed tractor power was confirmed. For the given conditions (sowing days, sown area), various sowing units were selected and the costs of their operation were calculated. As a result of mathematical modeling, the operating costs of various sowing units are determined in standard and reduced tractor engine power options. To assess the specific operating costs of the sowing unit for processing a unit area, an appropriate indicator and its graphical interpretation are proposed. The dependences of the indicator of specific operating costs on the power of the tractor engine with its installed (nominal) value and reduced to 15 % are obtained. If the engine power meets the set value, the optimal sowing machine and tractor unit according to the criterion of minimum specific operating costs is the unit based on a wheeled tractor with an engine power of 125 kW, which corresponds to 2 or 3 drawbar category. It was found that a decrease in tractor engine power by 15 % from the installed one, due to a change in its technical condition, provides an increase in unit costs for sowing by 28,4 %.