Traction resistance of the machine when tilling fallow lands with a working body equipped with a flat knife

Abstract

The research was conducted in a field at the Siberian Research Institute of Forage. A special device was developed to measure the force exerted when cutting sod using a disc or knife coulter. The device consists of a rod with a strain gauge pressure sensor mounted on it connected to an electronic measurement unit, a handle, and a sector of the disc or knife coulter. The sector size is equal to 1/8 (161 mm) of the arc of the disk circumference with a radius of 205 mm; the sector angle is 45 degrees. With sod layer thickness of 98 ± 4.5 mm and soil moisture of 23.0-26.7%, the specific force of cutting the sod with a disk coulter is 40.72 N cm (4.15 ± 0.21 kg cm); the specific force when slitting the sod with a knife coulter is 38.28 N cm (3.83 ± 0.81 kg cm). Cutting sod with a disc coulter requires by 76% more energy than slitting it with a knife coulter. The field where the machine’s traction resistance experiments were conducted was a long-term fallow land that was not tilled since 2011. The soil was gray forest soil with a sod layer thickness of 98 ± 4.5 mm. The grass height at the time of the experiment was 20 cm. Traction resistance was determined with the machine operating at three speeds corresponding to the second, third, and fifth gears of an MTZ-80L tractor. A working element with a vertical blade was developed reducing the machine’s traction resistance during sod tillage by 10-20% compared to a working element without a blade on a fallow-field tiller. Moreover, at a speed of approximately 4 km h, the difference is significantly greater, reaching up to 22%; with an increase in speed to 10 km h, the difference decreases to 10%. Regression equations were obtained that reflected the change in the unit traction resistance depending on the speed of tillage of the sodded soil layer.