Design And Experiment Of Key Components Of Seed Ditch Reconstruction In Wheat Stripe Rotary Seeder

Strip rotary tillage is one of the core technologies of conservation tillage in the Huanghuaihai wheat and jade double cropping area.It has the advantages of reducing soil erosion,increasing soil organic matter,and improving the environment of seed ditches.However,after the harvested corn straw was returned to the field in the Huanghuaihai double-cropping area,the surface straw amount was large,and there was a lot of crushed straw in the seed belt after strip spinning,which resulted in too large pores in the straw-soil complex in the seed ditch,and the seeds could not fully contact with the soil,resulting in insufficient subsequent suppression intensity.Aiming at the above problems,the soil environment above the seeds in the seed gully was reconstructed,and the furrow side pick-up blade and press device was designed,which was suitable for wheat strip rotary tillage and sowing technology in the straw mulching area of Huanghuaihai.The main research contents and results are as follows:(1)Study on compressive strength characteristics of straw-soil mixed mediumThe simulation model of the straw-soil complex was constructed based on EDEM discrete element simulation software.The dynamic process of the complex was simulated by pressing plate down test,and the force transfer characteristics between straw-soil particles and the optimal straw content in the seed ditch were studied.The results show that the soil stress is the best when the straw content is 10%～30%.By comparing the results of laboratory test and simulation,it is concluded that the simulated value of soil stress and the experimental value have the same variation trend,and the average error of both is 12.33%,which provides a theoretical basis for the reconstruction of seed ditch and the design of subsequent the furrow side pick-up blade.(2)Based on the chisel ditch opener the furrow side pick-up blade designTo improve the environment of the trench and achieve the best straw content of the trench,the furrow side pick-up blade at the side of the trench was designed based on the chisel ditch opener.By taking wet soil on both sides of the trench for soil covering,the quality of soil covering was improved and the content of culm in the trench was reduced.Three factors and three levels of orthogonal combination tests were carried out according to the principle of plow wing surface and the simulation model of the furrow side pick-up blade-straw-soil.The experimental results show that when the forward speed is 4.86km/h,the endpoint tangent angle is 107.17°,the angle of soil entry is 5.46°,the soil covering thickness is 40mm,and the proportion of straw in the trench is 21.46%.The optimal parameters were combined to carry out the soil bin test on the indoor bench.The results showed that the thickness of the soil cover was 40.4mm and the proportion of straw in the trench was 18.03%.(3)Design and research of"M"type press wheel based on seed groove contourThrough the soil groove opening test on the indoor bench,the seed groove type of the soil reconstituted by the furrow side pick-up blade was mapped,and the shape design of the"M"shaped press wheel was determined according to the seed groove shape.By theoretical analysis and EDEM-Recur Dyn coupling simulation,the suppression effect of three factors and three levels of orthogonal combination tests are carried out.The results showed that the order of influence of various factors on soil bulk density was:seed ditch contact width>external load>internal dip angle.Using Design-Expert to optimize the parameters,the results were as follows:the external load Q=650N,the contact width B=44mm,the internal dip Angleθ=30°,and the soil bulk density was 1.3g/cm~3.(4)Experiment of key components for seed trench reconstruction assisted suppressionCombined with the combination of the furrow side pick-up blade and the"M"type press wheel,comparative tests of the furrow side pick-up blade and the"M"type press wheel were carried out in the soil bin.The results show that the average depth of soil cover with the furrow side pick-up blade is 35.6mm,which is 41%higher than that without the furrow side pick-up blade.The straw coverage rate is 19.35%,which is within the range of the optimal value(10%～30%).The average soil compactness of the"M"type press wheel was496.2k Pa,which was 63.6%higher than that of the traditional press wheel.The results of the soil bin test are similar to those of the simulation and laboratory bench test,indicating that the combined soil covering press device meets the design requirements.