Development Of Multi-point Monitoring And Automatic Drip Irrigation System For Greenhouse Environment Based On Narrowband Internet Of Things

In recent years,with the continuous development of irrigation technology in my country,intelligent irrigation technology has been adopted in most areas of the country.For a large greenhouse area,the supporting Io T drip irrigation system often has the disadvantages such as a small number of nodes that can be mounted,a small coverage area of equipment networking,and high-power consumption during transmission etc.In view of the inflexible networking of the current Internet of Things drip irrigation system,the low utilization rate of water and fertilizer,the unreasonable drip irrigation system,and the single collection of data points,this paper designs a greenhouse environment multi-point monitoring and automatic drip irrigation system based on the narrowband Internet of Things LoRa technology,which can realize the long-term monitoring and collection,storage and remote transmission of plant growth data at multiple points,and use different irrigation rules for irrigation according to different growth stages of the plant.The main research content and conclusions of this article are as follows:(1)Accomplish the design of drip irrigation systemThe water is transported to the greenhouse area by centrifugal pumps,a set of laminated filters is installed at the head of the system to filter the water source,and a constant pressure water supply device is used to complete the layout of the pipe network,the selection of equipment,the determination of parameters,and the hydraulic calculation of the drip irrigation system,then the design of the entire drip irrigation system is completed.(2)Hardware design of environmental multi-point monitoring systemThe design and selection of LoRa gateways,terminal nodes,STM32 modules,sensors and solenoid valves is completed,the design and commissioning of various drive circuits is completed,as well as the establishment of a greenhouse environment multi-point monitoring system based on the narrowband Internet of Things.Within the deployment scope of the gateway,collect the environmental parameter information of each node and remote control of the corresponding output IO port.(3)Software design of environmental multi-point monitoring systemThe software is designed,the environmental information collection and protocol stack communication programs is composed,the design of LoRa gateways and the design of terminal nodes and network access is completed,a cloud platform built,data display and storage,instruction issuance,configuration screen and mobile phone design accomplished.(4)Accomplishment of the design of drip irrigation system control rulesUsing the greenhouse area as the test environment,conduct multi-point environmental monitoring system test,water and fertilizer test,test the time required for the soil wetting peak to reach the root of the plant and the change of soil moisture,soil temperature,electrical conductivity,p H value,etc.with drip irrigation time,design Control rules and methods,corresponding to plants at different growth stages,design and complete different irrigation control rules for drip irrigation operations,and complete automatic control and adjustment.The main conclusions are drawn from the above research:(1)The success rate of communication in the cucumber greenhouse experiment is over90%,and the coefficient of variation of soil moisture content in the vertical and horizontal directions is 12.0491% and 11.674%,respectively.Compared with single-fertilizer irrigation,clear water wets the soil layer after 5cm,7cm,and 10 cm.The time for electrical conductivity to stabilize has been shortened by 13.33%,18.33%,and 21.67%,respectively.Soil electrical conductivity is negatively correlated with p H changes.In the seedling stage,drip irrigation reaches 45 min to reach the saturation of soil moisture and completes the irrigation;in the early blooming period,clear water drip irrigation for 9min,fertilizer drip irrigation 49 min,flush the pipeline and drive the fertilizer liquid to continue to move downward for 17min;during the fruit preservation period,clear water drip irrigation for 9min,fertilizer drip irrigation for 49 min,clear water drip irrigation for 25 min,The conductivity reached the peak value of 700μS/cm,and the irrigation is completed.(2)The coefficient of variation of soil moisture content in the vertical and horizontal directions of the grape greenhouse test was 11.5877% and 11.3434%,respectively.Compared with single fertilizer irrigation,the time for soil conductivity to stabilize after wetting 5cm,7cm,and 10 cm with clean water shortened respectively.12.5%,16.67%,20.83%,seedling stage,drip irrigation for 50 min to reach the saturation of soil moisture;in the first flowering stage,clear water drip irrigation for 16 min,fertilizer drip irrigation for 53 min,flush the pipeline and drive the fertilizer liquid to continue downward movement for 21min;fruit swelling stage,clear water drip irrigation for 16 min,Fertilizer drip irrigation for 53 minutes,clear drip irrigation for 28 minutes,The conductivity reached the peak value of 820μS/cm,and the irrigation was completed.(3)The experiment proved that drip irrigation with water and fertilizer can adjust the irrigation control rules for different growth stages of plants and improve the utilization rate of water and fertilizer.The system meets the design requirements and is feasible.