Research On Light And Simplified Fertilizer Irrigation Control System

As the fact that the crops planted by greenhouse soil-less cultivation need to imbibe moisture and obtain nutrients from the irrigation nutrient solution,it is of great significance to research integrated irrigation system,which is sure to improve the utilization of facilities agricultural water and implement scientific irrigation and fertilization.To improve the status quo of integration of irrigation water,a set of simplified fertilizer irrigation system making use of the embedded controller and HMI touch terminal was designed in this paper.The system can monitor the environment information and liquid fertilizer information and control irrigation actuators in the real time.At the same time,according to the different nutrient requirement of crops under different developmental period,the system analyzed and formulated the fertilizer proportion providing a decision-making basis for the precision mix of water and fertilizer.The experiments proved that this system is stable and reliable,easy to use and can be used for soilless cultivation.The design of the irrigation system is based on the short form principles.The main body of the system was made up by aluminum and universal wheel,which made the airframe easy to move.Control system was made up by the STM32 controller,Ec sensors,analog acquisition module,relay module,HMI touch terminal and other parts.STM32 gathered the environment information and liquid fertilizer information with the help of analog acquisition boards and realized the information interaction with the HMI touch screen.The human-computer interaction interface displayed the parameter information and listened for the irrigation and fertilization command in the real time.Then we could control relay to complete irrigation or fertilizer task.The irrigation quantity algorithm of this system is based on the Penman-Monteith equation.The irrigation amount depends on the crop transpiration.And achieve precise irrigation by controlling the irrigation time.The system provided two kinds of modes:manual control and automatic control.When the Manual mode is chose,the drip irrigation amount is determined by the user;When the automatic control mode is choose the drip irrigation duration is determined the results calculated by the Penman-Monteith equation.The research object of this study was cucumber,Xinjinchun No.4.The nutrient solution prepared based on the cucumber irrigation mature formula preparation.The experiment calibrate the nutrient solution dilution ratio.So the system could choose a proper irrigation strategy according to the different nutrient requirement of crops under different developmental period.The irrigation system was tested in the greenhouse:(1)In order to eliminate the problem that the nutrient solution was mixed unevenly,the mother liquid need to be mixed at least 3 min before irrigation.The precision error of the Ec information is less than 0.02(mS·cm-1),the standard deviation less than 2.83%,which could satisfy the requirement of the irrigation in the greenhouse.(2)This paper analyzed the Ec distribution effect of the irrigation fluid under the condition of different irrigation pressure and different nutrient solution proportion.The results showed that the pressure,the proportion of nutrient solution(that was the Nutrient solution concentration)and the distance to the main pipe all had a great influence on the Ec distribution effect.According to the experimental data,when the pressure is 0.32 MPa,it took 6 mins to make the Ec of the nutrition solution achieve stability.The experimental data provides a theoretical basis and practical basis for the application of the system used in the greenhouse.