Optimal Design And Experimental Research On The Layered Fertilizer Apparatus Of The Specific Row-following Layered Fertilize

Precision-to-row stratification is one of the most important technologies for improving fertiliser utilisation,but high resistance to the work of stratification devices,poor stratification accuracy and congestion of residuals have become the main problems currently limiting development.This paper therefore addresses these issues by designing a precise pair of row layered fertiliser based on the original layered fertiliser device and based on the male dung beetle’s angular protrusion profile.A combination of discrete element simulation and soil tank tests was used to optimise the structural parameters and operating speed of the stratified fertiliser application unit.The optimised stratified fertiliser application unit was investigated in field trials for fertiliser distribution accuracy and residual congestion.The main research elements and findings are shown below.(1)Determination of fertilizer and soil particle parameters.In this study,the material parameters of fertilizer and soil were determined,mainly including fertilizer particle density,three-dimensional dimensions,thousand particle weight,static friction coefficient,elastic modulus and collision recovery coefficient,soil density,particle grading,rest angle and friction angle,etc.,using Shihezi area soil,poly-pure organic fertilizer,Jintun diammonium phosphate and Yihua urea as research objects,to provide reference for the selection of discrete element simulation parameters of layered fertilizer application device.(2)Optimal design and force analysis of a layered fertiliser application device.A layered fertiliser application device was designed based on the male dung beetle angle protrusion profile.The force analysis determined the parameters affecting the working resistance of the layered fertiliser application device,including the front edge angle,side plate mounting angle,shovel width and operating speed.(3)Discrete element simulation optimisation of the structural parameters of the stratified fertiliser application unit.The simulation tests were carried out with the front edge angle,the side plate mounting angle and the shank width as test factors and the working resistance of the stratified fertiliser application unit as test indexes.The optimization ranges for the front edge angle,the shank width and the side plate mounting angle were determined to be 55°～65°,19～21mm and 6.3 ° ～7.3 ° respectively.The results of the three-factor,three-level orthogonal combination test show that the front edge angle has a significant effect on the working resistance and the side plate mounting angle has a significant effect on the working resistance.The optimized structure parameters are: front edge angle 60°,side plate mounting angle 6.3 °,shank width 19 mm,and the working resistance of the layered fertilizer application device is 1427.88 N.The optimal operating speed of the layered fertilizer application device is 6km/h.The optimized layered fertilizer application device has better working performance.(4)Soil trench test and field test.The soil trench test was used to verify the drag reduction effect of the optimised shovel type 3 compared to the original shovel type 1 at different operating speeds(5km/h,6km/h and 7km/h).The results show that at operating speeds of 5km/h,6km/h and 7km/h,the drag reduction rates were 30.25%,29.49% and27.82% respectively.Field trials were conducted to compare the optimisation effect of the two stratification devices before and after optimisation in terms of fertilisation effectiveness,stratification accuracy and cotton stem congestion.The study showed that the spacing between the upper and lower layers of fertilizer of the two layered fertilizer application devices before and after optimization were 10 cm and 8cm respectively,with coefficients of variation of 14.19% and 22.81% respectively,and the upper layers of fertilizer of the two layered fertilizer application devices were mainly distributed in the range of 10-16 cm and the lower layers of fertilizer particles were mainly distributed in the range of 20-26 cm.The coefficients of variation for the two types of layered fertiliser application before and after optimisation were 27.76% and 24.44% for the upper and lower layers respectively,with both the upper and lower layered fertiliser ratios close to 4:6;the amount of cotton stem congestion in a 50 m length area was 1kg and 0.12 kg for the two types of layered fertiliser application devices before and after optimisation respectively.