Measurement And Transmission Of Plant Growth Information Based On Lpwan

In the process of plant growth,evapotranspiration is an important component of plant water balance movement.It plays an important role in the study of water consumption law and calculation of plant physiological parameters in the whole physiological cycle.In this paper,through the improvement of traditional lysimeter,the potted plant multi-point evapotranspiration measurement system and substrate plant growth monitoring system based on low-power WAN technology have been set up respectively,which can realize the noninvasive,real-time and accurate acquisition of plant growth,and physiology information.The main contents are as follows:1.Development of online evapotranspiration measurement system for multiple potted plants.The system consists of low power consumption potted evapotranspiration measurement nodes,gateways,and PC monitoring software.The gateway receives data from each potted plant measurement node through the formed LoRa star network,after packages the data and sent to the monitoring software through NB-IOT/RS-485 method.The PC monitoring software can acquire the weight of each pot online,and automatically calculate the hourly/day evapotranspiration rate of each pot.The system was tested by greenhouse lettuce experiments.The analysis results of the test data basically accorded with the law of evapotranspiration and water consumption of lettuce,which verified the feasibility of the system.2.Development of growth monitoring system for plants in substrate cultivation mode.The system includes low power acquisition node(evapotranspiration measurement,growth measurement,environmental collection),gateways and PC monitoring software.The software receives the data of each node through the gateway,and it can realize the online calculation of the parameters of evapotranspiration rate,growth rate,water content of the substrate,liquid recovery rate and so on.The system was tested by the substrate cultivation tomato experiment,and the tomato-related growth activities obtained from the analysis of the experimental data were consistent with the existing research,which verified the feasibility of the system.3.The measurement accuracy,network communication and power consumption characteristics of the system were tested.Firstly,the linear,creep and temperature drift characteristics of the load cell used in the weighing node of the system are tested,and the BP neural network algorithm is used for temperature compensation,The test results showed that the maximum error of the system in the range of-10 ? 50 ? and online weighing for 15 consecutive days is less than 1 g.Then,the normal communication of LoRa and NB-IOT transmission network in stand-alone and network mode is tested.Finally,the power consumption of each node was tested.For battery powered pot evapotranspiration measurement nodes and growth measurement nodes,the current is 70?74 ?A in the dormant state and the working time can be more than 120 days.For solar-powered environmental collection nodes,the current is 35 ?A in the dormant state,and it can work continuously for more than 50 days in a continuous cloudy environment.For substrate evapotranspiration measurement nodes and gateways powered by electricity,the maximum power is 0.38 W and3.74 W.