Design And Experiment Of Depth Monitoring System For Cotton Layer Fertilization

The application of chemical fertilizer has become a normal measure in cotton production.Scientific fertilization has been proved to improve soil fertility,be suitable for the absorption and utilization of nutrients by cotton,improve its canopy structure,and improve the efficiency of cotton photosynthesis,so as to achieve the purpose of increasing cotton yield.Before cotton sowing,the layered fertilization machine is used to apply the fertilizer in two layers to the soil to meet the needs of cotton base fertilizer and topdressing.The shallow fertilizer promotes the growth of cotton seedlings,and the cotton root system is exposed to deep fertilizer at the bud stage.One fertilizer application is divided into twice nutrient absorption to avoid fertilizer waste.However,the existing cotton layered fertilization machinery has difficulty in obtaining fertilization operation data.The operation performance with fertilization depth as the evaluation index can only be tested by manual measurement.The operation efficiency is low,there are human errors,and the fertilizer depth is always unknown.In order to solve this problem,this thesis designs a set of monitoring system which can reflect the real-time change of fertilization depth,which is conducive to improve the fertilizer utilization rate and crop yield,reduce the manual detection cost,and farmers have a rough evaluation of the yield,so as to test the operation performance of cotton layered fertilizer applicator.The main contents include:(1)Construction of mathematical relationship model of fertilization depth.It is proposed that the depth of the fertilizer shoe into the soil,the elevation of the bottom plate of the fertilizer outlet and the travel speed of the machines and tools are the influencing factors of the fertilizer depth.Taking the variation coefficient of the fertilizer depth as the evaluation index,the orthogonal test is carried out.The test results show that the depth of the fertilizer shoe into the soil,the elevation of the bottom plate of the fertilizer outlet and the travel speed of the machines and tools have different effects on the variation coefficient of the fertilizer depth.Through the interactive analysis of response surface,the optimal working parameters are determined.The results show that the optimized variation coefficient of the parameters is less than 8%.The optimized mathematical relationship model is obtained by nonlinear fitting of the experimental data with MATLAB,which meets the requirements of fertilization depth index,and provides a basis for the software design of fertilization depth monitoring system.(2)Hardware environment construction and software design of monitoring system.Through the selection of hardware such as inclination sensor,ultrasonic sensor and microprocessor,the real-time monitoring of fertilization depth can be realized.The circuit of fertilization depth monitoring system is designed by using Altium designer software,including single chip microcomputer control circuit,power supply circuit,sensor module circuit,serial communication circuit,display and alarm circuit,etc.The main program and each subroutine are designed,including the functions of sensor information acquisition,signal processing,data display and alarm.The real-time monitoring of fertilization depth can be realized.(3)Laboratory and field experiments of fertilization depth monitoring system.The sensor calibration soil tank test and the system test platform test are carried out.The results show that the average value detected by the sensor is close to the actual average value,which can reflect the change of the real distance,and the system detection data curve is consistent with the actual measurement data curve,which can accurately display the real-time data of fertilization depth.Finally,the field comprehensive verification test of the fertilization depth monitoring system is carried out.The results show that the field operation performance of the monitoring system is stable and can accurately reflect the actual fertilization depth;The stability coefficients of the upper and lower fertilization depth calculated by the mathematical relationship model are more than 85%,indicating that the reference value of the model is high and the fertilization depth reflected is more accurate.