Harrow with screw-type operating tools: optimisation of design and process parameters
¹Estonian University of Life Sciences, Institute of Forestry and Engineering, 56 Kreutzwaldi Str., EE51006 Tartu, Estonia
²National University of Life and Environmental Sciences of Ukraine, 15 Heroiv Oborony Str., UA03041 Kyiv, Ukraine
³Separated Subdivision of National University of Life and Environmental Sciences of Ukraine, Berezhany Agrotechnical Institute, 20 Academchna Str., Berezhanu, Ternopil region, UA 47501, Ukraine
⁴National Academy of Agrarian Sciences of Ukraine, 9 Mykhailo Omelyanovych-Pavlenko Str., UA01010, Kyiv, Ukraine
⁵National Science Center, Institute of Agriculture of NAAS of Ukraine,
2-b Mashynobudivnykiv Str., Chabany vil., Kyiv-Sviatoshyn Dist., UA08162 Kyiv Region, Ukraine
A new design of the harrow with screw-type operating tools is presented in the paper. It describes the theoretical and experimental investigations carried out for the purpose of optimising the design and process parameters of the harrow with screw-type operating tools. Such optimisation will provide for improving the soil fertility, when burying chaff and other plant residues as organic fertilisers into the soil during its tillage. On the basis of the results obtained in the comprehensive experimental investigations, new regression relations have been generated. These relations provide for determining the proportion of the field surface, where the after harvesting residues have been completely buried in the soil with the harrow with screw-type operating tools. It has been established that the dominant effect on the relative amount of the field surface area S with completely worked-in plant residues is produced by the soil tillage depth h, then follows the factor of the screw-type operating device battery approach angle β. The pitch distance Т of the screw-type operating device has the smallest effect. The results of the completed research prove that increasing the pitch distance Т of the screw-type operating tool from 0.18 m to 0.26 m results in the decrease in the area S of the field surface with the plant residues buried in the soil by 1.4%. An increase in the approach angle β from 20° to 40° results in the increase in the field surface area S with the plant residues completely worked into the soil by 5.6%. Increasing the soil tillage depth from 0.08 m to 0.12 m results in the increase in the above-mentioned surface S by 7.1%. The simultaneous action of the factors of the tillage depth h and the approach angle β results in the percentage of the surface S rising from 72% to 82%.