In the article theoretical preconditions of a description of dynamics of manoeuvrability of machine-tractor, aggregates with a wheeled-tracked mover are considered. For a machine-tractor aggregate with half-tracked progress theoretical formulas of determination of an actual turning radius, the moment of resistance of turn and torque for rotation are obtained. The theoretical preconditions are confirmed by experimental research of the manoeuvrability of the machine-tractor aggregate with the tractor on a halftracked progress, made as the experimental sample. The dependences of the turn coefficient and the resistance coefficient of the turn are obtained, and the correlation coefficients and their significance have confirmed the existence of a stable connection between the changing parameter and the response function. Proceeding from theoretical and experimental research, it is possible to draw a conclusion that the manoeuvrability of the tractor with a wheeled-crawler mover does not concede to the tractor in the basic execution.

The article is devoted to the search for ways to reduce carbon dioxide emissions into the atmosphere when performing technological operations in agricultural production. It is proposed to calculate the efficiency of using machine and tractor units based on the methods of physical economics, when not a monetary unit is used as an indicator of efficiency, but an energy unit, which is an indirect indicator of saving or increasing emissions of carbon dioxide. It is substantiated that a decrease in total energy costs when performing technological operations for the production of grain and other crops directly leads to a decrease in greenhouse gas emissions into the atmosphere. Examples of computational experiments are given to identify the most optimal brand of a tractor and optimize the parameters of the working width and speed of the seeding machine-tractor unit K-5250 + Agromaster, leading to a decrease in total energy costs and, accordingly, to a decrease in carbon dioxide emissions and carbon sequestration from the air by reducing losses harvest

To identify the main parameters of the tractor - its mass, engine power, wheel diameter and its profile width (four-parameter optimization) using the optimization criterion - the total energy costs (taking into account the energy of the crop lost due to the non-optimality of these parameters), it is necessary to have a mathematical model for calculation of engine power through the traction coefficient of performance of the tractor. The traction efficiency of the tractor is calculated through f is the coefficient of resistance to rolling of the tractor wheel and d is the coefficient of slipping of the tractor wheel. An analysis of the applied theory developed by previous researchers showed that the values f and d depend on the weight of the tractor coming to one wheel G, the diameter D and the width of the profile of the wheel B, the pressure in its tires ρw, the hardness of the soil H, the effort on the tractor hook Pkp and its speed V. During the analysis, it was found that the larger the diameter of the wheel, the width of the tire profile, the less the vertical load on the wheel and the pressure in the tires, the less the resistance to rolling the wheel over the soil being compacted. It is concluded that the study of the nature of the change in the coefficient of resistance to rolling wheels f and their slipping d from the above factors must be carried out jointly, because they influence each other. The absence of acceptable mathematical dependences for calculating the indicated coefficients, with the simultaneous action of all identified factors, leads to the need for a seven-factor experiment to identify the dependencies f =j (G, D, b, ρw, H, Ркр, V) and δ =ψ (G, D, b, ρw, H, Ркр, V), which is very difficult in operating conditions, therefore, using the similarity theory, it is necessary to reduce the number of factors in the experiment to four.

The article provides an overview of the state of the art related to the emission of greenhouse gases into the atmosphere during the operation of mobile machine-tractor units in the agricultural sector of the economy. Sources of greenhouse gas emissions are considered. It was revealed that a huge amount of greenhouse gases are emitted into the atmosphere due to intensive soil cultivation, while the emission of CO2, NOX and CH4 is many times higher than the emission of these gases from fuel combustion in the engines of machine and tractor units. However, taking into account the large areas of arable land in the Russian Federation, reducing the emission of greenhouse gases with exhaust gases (OG) of engines is an urgent task. The article discusses the composition of the exhaust gases of a diesel engine and methods of binding environmentally harmful substances, considers ways to reduce the emission of toxic components of exhaust gas. It was revealed that of the gases contributing to the formation of the greenhouse effect on the ground, up to 10% of exhaust gases contain carbon dioxide. In this regard, the ways of reducing the emission of carbon dioxide from the engines of machine-tractor units are being analyzed, the tasks of research on the binding of CO2 in soil and plants are set, by using some chemical fertilizers as substitutes, for heating the soil at the time of sowing and activating the vital activity of beneficial microorganisms in it. It is stated that one of the ways to reduce CO2 emissions into the atmosphere is to search for ways to reduce direct and indirect energy costs during the operation of machine-tractor units, including by reducing crop losses due to incorrectly selected parameters of tractors and agricultural machines, neg