Design And Experiment Of Rapeseed Straw Crush Rotary Tillage And Burial Returning Machine

Aiming at the problems of thick stalks for rapeseed,large stubble retention and difficulty in decomposing after returning to the field,resulting in poor rooting of subsequent crops after sowing.A kind of rapeseed straw crushing rotary tillage burial returning machine which can realize straw crushing and uniform burial was designed to improve the uniformity of straw burial and promote straw decomposition,the main research contents and conclusions are as follows:(1)The effects of straw length and burial uniformity on the decomposition rate of rapeseed straw were investigated by a two-factor five-level orthogonal experiment under the conditions of a certain amount of straw and depth of return,the results showed that when the straw length is 2 cm and the number of straw bags is 22,the straw decomposes best,and the decomposition ratio is 69.38%at this time,the more uniformly the straw is buried(expressed by the number of different bags of equal quality),the faster the straw decomposes.A three-factor,five-level orthogonal rotating combination experiment was used to investigate the effects of straw length,burial depth and return volume on the decomposition ratio and decomposition rate of rapeseed straw under certain conditions of burial uniformity.The best decomposition effect was achieved when the burial depth was6.53 cm,the straw length was 2 cm,and the return volume was 863.65 g/m~2,with a decomposition ratio of 60.41%and a decomposition rate of 1.43 g/d.The above experiment showed that the shorter the straw crushing and the more uniform the burial cover,distributed at a depth of 6.53 cm,the more favorable the decomposition.(2)Completed the design of the returning machine for crushing,rotary tilling and burying of rapeseed stalks.Using the straw crushing-rototilling-buried return process,the rapeseed straw crushing-rototilling-buried return machine was designed,including a horizontal crushing device,a rotary tillage device,an opposed double-spiral burying device and a transmission system.The power of the whole machine is transmitted from the PTO output to the middle gearbox,and the middle gearbox drives the rotary blade roller while diverting the power to the left and right gearboxes,with the left gearbox driving the crushing blade roller and the right gearbox driving the burying roller to achieve stable operation of the blade roller.According to the straw crushing and spreading angle and rotating tillage blade roller speed,the horizontal spacing between the crushing blade roller and rotating tillage blade roller,the vertical spacing and the horizontal spacing between the buried roller and rotating tillage blade roller were determined.(3)Parameter design and optimization of opposed double spiral buried rolls.The effect of opposed double-spiral burying rolls on the spatial uniformity of straw distribution in soil under rototilling operation was carried out,the experimental results showed that the spatial uniformity of straw distribution was better after the rotary tillage-burying operation.Compared with the rotary tillage operation,the coefficient of variation of straw mass decreased by 9.26%,5.56%and 6.43%in vertical,horizontal and vertical directions,respectively,and the straw mass increased by 16.11%in the 5～15 cm soil layer after the rotary tillage-burial operation.The structure design of the opposed double spiral burying roller was carried out,and the spiral lift angle of the burying roller was determined as 58.92°,the pitch as 2344.21 mm and the turning radius as 225 mm.A four-factor,four-level orthogonal experiment was conducted to optimize the parameters of the opposed double-spiral burying roller with the distribution uniformity of rapeseed straw in the soil as the evaluation index,and the best combination of operating parameters for the opposed double-spiral burying roller was obtained with a spiral lift angle of 60°,a burying roller speed of 210 r/min,a forward speed of 0.6 m/s and a straw length of 6 cm.(4)Field experiment of rapeseed straw crushing,rotary tillage and burial returning machine.Based on the evaluation indexes of straw crushing length qualification rate,straw burying rate and burying uniformity,measured the operation effect of the whole machine in the field.The experiment results show that,after the operation,the straw crushing length qualification rate is 89.18%,the average crushing length of straw was 7.3cm,the straw burial rate is 91.45%,the straw is evenly distributed in the soil,the coefficients of variation of straw quality were 19.94%,17.32%and 14.65%in the vertical,horizontal and vertical directions respectively,and the straw content in the soil layer of5～15 cm reaches 58.02%.it effectively improves the degree of straw crushing and uniformity of burying,which can promote the rate of straw decomposition and provide high-quality seedbed for the next crop planting.