Research On A Bivariate Monitoring System For Corn Fertilization

As a major agricultural country in my country,corn is one of the main field crops in China.According to the requirements of precise variable fertilization in corn production,this paper designs a dual-variable corn fertilization control system.By studying the flow signal of the fertilizer falling during the fertilization operation,the fertilization signal is subjected to two filtering and denoising processing,and the optimal processing method is selected from the fertilization signal.Real-time monitoring of the fertilization amount of corn fertilization operations,The research content is of great significance for improving the real-time flow detection of corn fertilization and ensuring accurate variable fertilization.The main research contents of this paper are as follows:(1)Take the granular fertilizer(diammonium phosphate,urea and nitrogen-potassium compound fertilizer)used in corn fertilization as the research object,and determine the physical and mechanical properties of the selected granular fertilizer,including the three-dimensional size,sphericity,and true density of the particles.And the bulk density,its angle of repose and stiffness coefficient.The tests show that the sphericity of the three types of granular fertilizers is more than 80%,the maximum particle density is1.532 g/cm~3,and the true density is 1.679 g/cm~3.The maximum angle of repose is 38.488°.(2)Analyze the main factors affecting the state of fertilization,determine the overall plan of the bivariate fertilization system,including the selection of fertilizer applicator drive device and data acquisition device;Designed a dual-variable fertilizer applicator,which mainly includes hydraulic drive control module,computer control query module,locomotive operating speed Beidou/GPS acquisition device,single-chip MCU control unit,fertilizer application amount acquisition sensor,etc.(3)Develop a monitoring system for fertilization status.The experiment uses the microwave Doppler sensor as the core detection module.Through the bench test of granular fertilizer flow measurement,the data acquisition instrument is used to collect the falling speed signal of the fertilizer particles in the fertilizer pipe.Monitor the flow rate or the state of fertilizer exhaustion during normal fertilizer discharge in the fertilizer discharge pipe,and perform two filtering and denoising methods on the collected noisy signals,namely wavelet transform and wavelet packet transform.Comparing the processed waveforms and signal-to-noise ratio of wavelet transform and wavelet packet transform,we finally choose to use low-frequency wavelet decomposition and reconstruction method to remove noise.(4)In order to verify the performance of the designed dual-variable corn fertilization monitoring system,indoor and field experiments were carried out.Calibrate the amount of fertilizer discharged through laboratory tests;test the communication stability between the nodes of the system through field trials.The test results show that the change trend of the fertilizer volume detected by the microwave Doppler sensor module is consistent with the actual fertilizer volume under the fertilizer status,and the average error is 7.68%.