Specific draught, soil fragmentation and straw incorporation for different tine and share types

This study measured the specific draught (force per cross-sectional area of worked soil) and the energy use for soil fragmentation and straw incorporation using different tillage implements (mouldboard plough, 80 mm tine with and without wings, 210 mm sweep share, 80 mm rigid and vibrating tines) on a clay and a loam soil. Tine widths of 50, 65, 80 and 120 mm were compared in a separate experiment. Draught was calculated from measurements of fuel consumption and driving speed during tillage, while tillage depth was determined by weighing the loosened soil, which was also sieved to determine the aggregate size distribution and surface area. Measured values of specific draught were compared with model computations.Specific draught was much higher for the rigid 80 mm tine than for the mouldboard plough and sweep share. On the clay soil, specific draught was 65 kN m−2 for the mouldboard plough, 140 kN m−2 for shallow tillage with the rigid tine, 98 kN m−2 for the vibrating tine and 65 kN m−2 for the sweep share. The vibrating tine had a much lower energy use for soil fragmentation than the rigid tine. The sweep share also had a low energy use for fragmentation, but the poorest incorporation of straw. On the loam, differences between treatments were generally smaller than on the clay. There were small differences in specific draught and soil fragmentation for different tine widths. For the different tines and shares, the measured specific draught was considerably higher than values from model computations.Overall, there were great differences in draught requirement and tillage outcome for the different tillage tools. The results show the importance of adjusting the tillage tool to achieve the desired tillage outcome in terms of soil loosening, soil fragmentation or incorporation of plant residues.

Research highlights▶ There were clear differences in specific draught between different tine and share types, with the lowest specific draught recorded for mouldboard plough and sweep share. Both these tillage tools are characterised by small rake angles and a cutting action on the soil. ▶ A vibrating tine had a relatively low specific draught and created a high soil specific surface, which resulted in a low energy for fragmentation compared with a rigid tine. ▶ The sweep share also had a low energy for fragmentation, but poor incorporation of straw. ▶ The results show the importance of adjusting the tillage tool to the desired tillage outcome in terms of soil loosening, soil fragmentation or incorporation of plant residues.