Study On Technology And Development Of Equipment Of Fertigation In Field Micro-spray Irrigation

Fertigation technology is an important measure to ensure that fertilizers go with water,fertigation on-demand,and saving water and fertilizer.The grain production in China faces the problem of shortage of water resources,the supply of water and fertilizers in traditional farmland irrigation is not synchronized,water and fertilizer utilization efficiency is low,and due to the imperfect irrigation system of the pipeline network.This paper relies on the major agricultural application technology innovation issues in Shandong Province,taking the typical crops of wheat and corn in field as examples to study the key technologies of fertigation based on the micro-sprinkler irrigation model,including:realize three-stage fully automatic irrigation and fertilization according to real-time lyrics and growing season;design a mobile irrigation and fertilizing integrated machine and a switching control method including Smith Predictor to realize fast configuration of mother liquor and uniform injection of precision;using an improved genetic algorithm for multi-objective optimization of the field pipe network to determine the optimal width of micro-spray belts,establish a low-cost,high-uniformity,suitable for wheat and corn micro-sprinkage irrigation field network layout mode.The specific research in this paper mainly includes the following five parts.1.Three-stage irrigation fertilization time allocation modelThrough the analysis of the annual demand for water and fertilizer in wheat and corn,the importance of supplemental irrigation and the need of top dressing in wheat and corn production was determined.The amount of irrigation and the amount of fertilizer used in each irrigation fertigation operation were calculated,and a time allocation model for irrigation and fertilization was established.Three-stage irrigation fertilization method was designed to realize fully automatic irrigation and fertilization operations from surface pre-rinsing,irrigation,fertilization and scouring pipe network,which effectively improved the utilization rate of fertilizers.2.Mobile irrigation and fertilizing one machine structure designComplete the design of the mechanical structure of mobile irrigation and fertilization one machine.The modular design of the mobile stand,the precision fertilizer device and the head hub of the one-piece machine was mechanically designed.The type of row fertilizer was selected,the selection of each part was determined,the porous fertilizer structure was designed,three-dimensional modeling was performed,and the uniformity of injection fertilizer was simulated based on Fluent.The method of ensuring the uniformity of the pipe fertilizer by the three-hole injection fertilizer method was obtained.3.Optimal design of integrated irrigation and fertilization controlTaking wheat as an example,based on different long-term water and fertilizer requirements of crops,combined with real-time measurement of soil moisture information,according to the flow rate to determine the relationship between fertilizer and water,to achieve accurate injection fertilizer,to design a dynamic calculation method of mother liquor concentration,and to establish a mathematical model for dynamic regulation of mother liquor concentration.In order to solve the problem of different dissolution time of different types of granular fertilizers,a rapid and stable mother liquor concentration with Smith Predictor switching control method was designed,and the control method was simulated and verified through Simulink.On this basis,the central control system of the integrated machine was designed and implemented.Integrated irrigation fertilization time allocation model and dynamic regulation of mother liquor concentration,realizing accurate regulation of fully automatic irrigation and fertilization functions and mother liquor concentration.4.Optimization of field pipe network with micro sprinkler irrigationBased on the study of the suitable water and fertilizer integration mode of wheat and corn,and the distribution characteristics of the micro-sprinkler irrigation water in the field,the hydraulic performance of the different models of micro-spray belt was obtained through the hydraulic analysis of the field pipe network system.Based on the improved genetic algorithm,parallel selection method was used to carry out multi-objective optimization of the field pipe network,and the optimal width of the micro-spray belt for the micro-sprinkage irrigation field network was determined to be 2.2 meters,and the pipe network per unit area of the irrigation unit was determined.The cost is 4968 yuan/hm~2,and the irrigation area of each irrigation unit is 790m~2,which saves 407 yuan per hectare when compared with the experience of the field network layout,which effectively saves costs.5.Complete the processing of the test stand and the two prototypes,and carry out a large number of on-site tests in many places.The test shows that the EC response curve of the four types of granular fertilizers during the fertigation process is a three-stage change,indicating that the all-in-one machine can be allocated according to time.The model carries out three stages of irrigation and fertilization operations;in the fertilization stage,the EC value is stable,the fluctuation range of the error is small,the over-time is short,the slope is steep,and the overshoot is small,indicating that the adaptive switching control will use different control methods according to different delay times,and quickly realize the dynamic regulation of mother liquor,effectively reducing the delay time,increasing the fertilizer utilization rate,realizing the greatest degree of water saving,fertilizer saving and cost saving are of great significance to improving the economic,social and environmental benefits of modern agricultural development.