Design And Test Of Seed And Fertilizer Separate Device Based On Active Soil Covering

Positive fertilization is the commonly used fertilization method in the seeding operation.Aiming at the problems of unstable seed and fertilizer spacing and insufficient soil covering of seeds in the case of natural fertilization,the active soil-covering method was adopted to design a seed and fertilizer distribution device based on double-disc soil covering.The device can effectively ensure the seed and fertilizer spacing and cover the soil of seeds at the same time.In this paper,the combination of discrete element simulation and field experiment is used to study the effects of structural parameters of seed and fertilizer application device on seed and fertilizer spacing and seed cover soil thickness.The research and development design of the fertilizer application device provides a basis.The main research conclusions of this paper as follows:?1?Determination of physical property parameters of soil,fertilizer and corn and construction of simulated particle model.The parameters such as soil moisture content,density and hardness were measured;The density,three-dimensional size and elastic modulus were measured by using diammonium phosphate and Zhengdan 958 as simulated modeling materials;Based on the measured results,a particle model of soil,fertilizer and corn seed was established in discrete element software.?2?Structural design of device for seed and fertilizer application.According to the technical requirements of seed and fertilizer application,it is proposed to adopt the active soil-covering method to realize the seed and fertilizer application,and determine the seed and fertilizer application scheme based on double-disc soil covering.The two sides of the groove soil are placed by the soil-covered disc installed behind the opener.The soil is actively covered back into the ditch,the fertilizers and seeds are covered with soil.The key structure of the seed and fertilizer application device based on double disc covering soil is designed and based on this.The motion model of the soil-covered disc and the soil is established.The total displacement of the soil particle space on the soil-covered disc is related to the advancement speed V₁ of the machine,the opening angle?,and the radius R of the disc.?3?The effects of structural parameters of seed and fertilizer application device on seed and fertilizer spacing and seed cover soil were studied.A discrete element simulation model based on double-disc soil-covering device was established.The single factor test and quadratic orthogonal rotation regression combination test were carried out respectively.The results show that the influence degree of each test factor on the thickness of seed cover soil is as follows:the spacing between the rear opening of the disc,the spacing of the front and rear of the seed tube,and the diameter of the disc;optimize the structural parameters of the seed and fertilizer application device,and obtain the best combination of the disc diameter of201 mm,the disc rear opening spacing of 103 mm,before and after the seeding tube spacing of 115mm.?4?Field contrast test study of seed and fertilizer application device based on double disc covering Soil.The mean relative error between test value and simulation value were 7.63%and 11.45%,respectively,indicating that the discrete element method can be used for seed and fertilizer application.The working effect of the device;the average spacing of seed and fertilizer spacing and seed cover soil thickness after operation of the double-disc soil covering device was 56 and 43 mm,respectively,and the coefficient of variation was 5.21%and 7.26%,respectively,with uncovered soil discs.Compared with the device,the seed and fertilizer spacing and seed cover soil thickness increased by 14.30%and 19.30%,respectively,and the coefficient of variation decreased by 7.78%and 8.14%,respectively.