Abstract

Theoretical analysis has been undertaken to determine the effect of the plough’s structural layout on the total length of the tractor- implement unit’s turning path. Basing on the results of the analysis, the utility of employing a reversible plough instead of a conventional one has been assessed. Eventually, it has been found that, when ploughing a 68.2 m wide land with an area of 8.2 hectares, the total length of the path of travel on the headlands is 1980 m for the reversible plough unit and 2035 m for the conventional plough unit, which is an increase by 2.7%. At an average manoeuvring speed of 1.75 m/s (6.3 km/h), the total amount of time spent for turning by a unit with conventional ploughing tools will be greater by mere 0.5 min. If the ploughed land is magnified by almost 1.5 times (12.0 hectares instead of 8.2), the width of the field will reach 100 m. In this case, the ploughing unit with a conventional plough will travel an 850 m longer path on the headlands. At the above-mentioned average headland manoeuvring speed of 1.75 m/s the increase of time spent by this type of tilling unit for turning will amount to just 8 min. The only advantage of the reversible plough over the conventional one is the opportunity to avoid the appearance of crown ridges and dead furrows when tilling the field. Meanwhile, it is to be noted that with a sufficient qualification of the machine operator the said advantage of the newer tilling implements can be levelled down. Considering the equal productivity of the compared tilling units, a negligible difference between their rates of non-productive expenditure of working time as well as taking into account the infrequent performance of ploughing, i.e. once in several years, in view of the considerably (several times) higher cost of a reversible plough, the acquisition of the latter presents an economically inadvisable option.