Design and test of lateral stubble cleaning blade for corn stubble field

Abstract: Non-till farming has attracted increasing attention in developing sustainable agriculture, but the straws and the stubbles left over after harvest could block dispatch of fertilizer and seeds in seed drilling, which could detach the seeds and soil and result in nonuniform seed drilling both vertically and horizontally. Therefore, developing devices able to clean and crush the corn straw on seedbed before fertilization and seed drilling/spraying are demanded. However, the existing blade in such devices for laterally cutting the stubbles cannot completely clean and transport the stubble. The leftovers in soil make seed drilling problematic as they could block seed dispatch, increase energy consumption and, under certain circumstances, even make the sowing device unbale to operate. In order to resolve these problems, we designed a device to laterally cut and remove the stubbles from corn field. In this paper, we analyzed its efficacy in stubble clearance, soil disturbance, energy consumption, as well as conveying and throwing the cut/cleaned stubbles. The optimal structure of the stubble-cleaning blade and the working parameters of the device were calculated by taking the bending angle of the blade α, the transverse cutting edge B, and the angular velocity of the blade ω as determinants, and the stubble clearance rate, soil disturbance rate and equivalent energy consumption of the blade as quantitative indexes of its performance, using the three-factor and three-level orthogonal test and the fuzzy comprehensive evaluation method. The results showed that the stubble clearance rate was significantly impacted by the bending angle, while the performance indexes were significantly impacted by the width and angular velocity of the blade. The factors that affected the performance of the device were ranked in the order of bending angle > transverse cutting edge > angular velocity. It was also found that soil disturbance rate was mostly impacted by the transverse cutting edge, followed by the bending angle and the angular velocity, while the equivalent energy consumption was mostly affected the transverse cutting edge, followed by the bending angle and the velocity of the cutter tooth angle. The optimized results for the device operation were that when the operation speed was 7.2 km/h, the bending angle was 0.86 rad, the transverse cutting edge was 50 mm, and the angular velocity was 52 rad/s, the associated stubble clearance rate was 94.3%, soil disturbance rate was 54.3%, and the equivalent energy consumption was 3.4 kW. Under these conditions, clogging and straw entanglement did not occur. The results in this paper are helpful for designing devices to clear straw and stubbles left over after harvest in no-till farming.