Design and Test of Rapeseed Seed Bed Preparation Device Combined with Parallel Plow Group Turnbuckle and Rotary Tillage

Abstract

Considering the problems of soil in mid-lower reaches of the Yangtze River is sticky and the amount of straw is large, the utilization of conventional rotary tillage rapeseed direct-seeding machines often leads to the plough layer is shallow and the straw coverage rate is low, the longitudinal size of the existing combination of plowing and rotary tillage rapeseed seeder is generally larger, the rapeseed direct-seeding agronomic requirement and the requirement were combined to build reliable plough layer, a parallel mounted buckling plough group was designed, a combined tillage operation scheme of “disc plow blade cutting and pressing stubble, parallel plow group turning over soil and burying stubble, the rotary tiller knife roll breaks up the clod and equalizes the soil” was proposed. The plough surface of the buckling plough was designed by using the method of straight ruled surface, the parametric analytical equation of plough surface was established, a simulation model for the interaction between tillage tool, soil, and straw was established based on the discrete element method, and the quadratic orthogonal rotation test was carried out to analyze the buckling performance of the buckling plough by using EDEM software. The simulation results showed that when the deflection angle θ was 12° and the change value Δθ was 11°, the buckling effect of the plough body was the best. Field experiments showed that the average soil buckling rate was 91.3% when the tilling depth was 230 mm and the forward velocity was 5.15 km/h, and the buckling plough had a good stubble burying effect. The parallel buckling plough group had good through performance under high crop straw conditions, with an average straw coverage rate of over 82.5%, an average tillage depth of over 218.6 mm, and a stability coefficient of over 90.2% for tillage depth. Field comparison experiment showed that under the condition of average stubble height of 513 mm after rice harvest, the average depth of rapeseed seed bed preparation device combined with parallel plow group turnbuckle and rotary tillage was 229.7 mm, the straw coverage rate was 87.5%, the soil breaking rate was 89.7%, and the planter bed surface flatness was 31.8 mm, compared with the operation effect of conventional rotary tillage, the average ploughing depth was increased by 90.9 mm, the straw coverage rate and soil breaking rate were increased by 7.2 percentage points and 6.5 percentage points, respectively, and the operation quality met the requirements of rapeseed direct-seeding, and met the requirements of reasonable cultivation layer construction of rapeseed seed bed of “deep turning and stubble burying, upper looseness and lower tightness”.

Keywords: rapeseed, seed bed preparation device, plow surface, parallel buckling plough group, plowing and rotary tilling