- Stoyanov1, K. Trendafilov2, N. Delchev1, G. Tihanov1
1Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria,
2Department of Mechanical Engineering, Faculty of Technics and Technologies – Yambol, Trakia University, 6000 Stara Zagora, Bulgaria
(Manuscript received 13 June 2018; accepted for publication 24 August 2018)
Abstract. The article presents the results of a field survey of the work of a spading machine. The influence of the following factors has been investigated: operating speed, deflector cover deflection angle and rotation speed of the power take-off shaft of the tractor on soil crushing. The relative share of aggregates smaller than 1 mm, from 1 to 10 mm, from 10 to 25 mm, from 25 to 50 mm, from 50 to 100 mm and over 100 mm has been determined. Regression relations have been created to determine the proportion of soil fractions of certain sizes depending on the controllable factors. The operating speed and the position of the machine cover have the greatest influence on the granulometric composition of the soil in cultivation with a spading machine. The resulting regression relations can be used to determine the operating parameters of the machine to achieve the desired granulometric composition of the soil depending on the purpose of the cultivation.