RESEARCH ON THE DEVELOPMENT OF THE TRACTOR AND COMBINE FLEET IN LATVIA

The article offers an analysis of the development of the tractor and combine harvester fleet in 2001 - 2016. There are stated tractors and combines of the most common brands registered in the country. A methodology has been developed for the estimation of an adequate quantity of tractors and combines for timely cultivation of the sowing areas under agricultural crops. The methodology is based on the calculation of the annual increase in the summary engine capacity of the entire fleet of tractors and combine harvesters, and its comparison with the annual increase in the sowing areas. It is assumed that 10% of the sowing areas are cultivated by worn-out tractors, and 7.5% of the new tractor and combine capacity is required for the replacement (amortisation) of the worn-out tractors. We consider that the increase in the summary capacity should compensate for the increase in the sowing areas, taking into account also the impact of the total yield upon the productivity of the machinery. It has been found out that during the period the summary engine capacity of the tractors has grown 1.52 times, the summary engine capacity of the combine harvesters - 2.8 times; in the same period the area under agricultural crops has increased approximately 1.38 times but the area under cereals and canola - approximately 1.8 times. Several authors consider specific capacity kWh(-1) as a criterion for the estimation of an adequate quantity of the machinery; therefore there are calculated also its changes in a 16-year period, with the specific capacity of both the tractors and combine harvesters increasing. The average specific power kWh(-1) is considered as relatively high, but, due to the concentration of production, a decrease in this indicator is possible in the future. The average weighted capacity of the purchased new tractors and combine harvesters has also increased. The increase in the summary capacity of the tractor fleet compensates for the increase in the sowing areas and even exceeds it a little. In its turn, the increase in the summary capacity of the combine fleet allows timely harvesting the significantly increased sowing area, and more than twice the increased totals yield at the end of the period, and, compared to the beginning, slightly shorten the harvesting duration. The calculations do not include weather conditions during the harvesting period. As increase in the sowing areas and total yield is expected still further, upgrading of the tractor fleet should be continued at approximately the same rate - by purchasing, on the average, 600 to 700 new tractors and 80 to 100 new combine harvesters every year.