Water irrigation area has characteristics of dispersion, rainfall variability, water supply timely requirement and water dynamic, coupled with the water conservancy project construction increase in recent years, more and more water conservancy facilities in the rural areas, make real-time monitoring and dynamic management of water conservancy facilities become very difficult. In this paper, based on LoRa / ZigBee wireless communication technology used in close range water-saving irrigation application, promote the automation and precision development of agricultural irrigation.
Keywords : water-saving irrigation, LoRa, ZigBee, telemetry terminal system
1. System Overview
Water shortage has become a global problem, as effective irrigation area of 937 million mu of farmland in China in 2014, only 51.5% of arable land, and nearly half of the arable land is “WangTianTian”, that lack of basic irrigation condition. Most of the existing irrigation and drainage facilities built in the 70’s of the last century, low standard, don’t match, aged disrepair and benefit attenuation problem. About 40% of the nation’s large irrigation area, 50-60% of the small and medium-sized irrigation areas, 50% of small irrigation’s water conservancy engineering facilities don’t match, large-scale irrigation and drainage pumping station equipment intact rate less than 60%. Irrigation and drainage facilities is still weak influence the steady development of agriculture and the national food security.
Precision agriculture irrigation control system construction, not only can improve the utilization efficiency of water resources, alleviate the problem of the growing scarcity of water resources, still can increase crop yield, reduce the production cost of agricultural products, to achieve maximum benefit. To realize the efficient utilization of water resources, with only a single technology is impossible to solve the water saving irrigation problem, must unification consideration of water resources development, water distribution, irrigation and rainfall, evaporation, soil moisture and crop situation, joint together precipitation, irrigation water, soil water and groundwater, implementation automatic supply water on schedule and on demand.
2. Systematic Design
2.1 Water-saving Irrigation
Based on LoRa/Zigbee wireless network intelligent water-saving irrigation system, through the arrangement of a large number of sensor nodes in the area of the monitoring network, which is formed by the real-time acquisition parameters (such as: temperature, humidity, soil moisture field, etc.), through the comprehensive analysis of the irrigation management system from remote terminal server, to realize the remote control switch of the valve.
The construction of the system content is as follows:
Based LoRa / Zigbee well irrigation system, through the star Internet architecture, which can realize water electricity measurement data of low power consumption, safe two-way data transmission service, to meet the centralized data remote transmission and low-cost operational requirements.
The construction of the system content is as follows:
3. System Integration
3.1 Industry Supervision
3.1.1 Integrated Design
The core equipment of system is telemetry terminal with high integration, high reliability, low power consumption and low cost advantages, maintenance is very simple, only need to replace the corresponding node module, can reduce the traditional control line equipment purchase cost, construction installation cost.
3.1.2 Network self-healing
Without human intervention, the network node can sense the presence of other nodes, and determined the connection relationship, form a structured network; When the node position change or failure, the network can repair themselves, and to the corresponding adjustment of network topology, guarantee the normal work of the system is stable.
3.1.3 The index system establishment
Water-saving irrigation control index system is the soil temperature, soil moisture, soil moisture content as the main evaluation factors, combining with the field observation and the proportion of the drought, crops representation of form a complete solenoid valve open and close and the opening of the valve linkage system, irrigation management platform to realize the automatic control of the water-saving irrigation system.
Wells irrigation management is based on agricultural water consumption, water consumption of crops and plot, administrative area water consumption as basis of statistical analysis, assist relevant institutions of the water rights allocation decisions.
3.2 Operational and Reliable
3.2.1 Transmission Security
Support multiple security levels, can be used in data transmission of AES encryption standard, and public key encryption in data exchange link adopted, in order to prevent illegal node access, ensure the security of data transmission.
3.2.2 Interference Immunity
By configuring the redundant nodes, can communication, collaboration, sharing data between nodes, can ensure the comprehensive data monitored nodes, and reduce electromagnetic interference in the physical layer using spread spectrum communication, in the application layer USES the secure multicast, can improve overall system error detection, fault tolerance and error handling ability.
3.2.3 Low-power Electronics
Under the premise of without sacrificing performance of the system, through the design to overcome, eliminate the idle listening, competition sending node, irrelevant data causing ineffective energy consumption such as excessive interference and channel allocation, to reduce power consumption, extend the life of the system.
3.2.4 Low Operational Cost
Compared with the traditional GPRS data transmission, LoRa / Zigbee data transmission requires no additional operation cost, can greatly reduce the operation and maintenance of project cost.
With the further development of wireless sensor network market, LoRa / Zigbee close range wireless communication technology, because of its own advantages, combined with the automatic control technology, water-saving irrigation technology, achieved through real-time acquisition soil moisture, soil temperature and humidity, field irrigation water consumption, account balance and other data, and by the LoRa / Zigbee wireless network connected to the water Internet, send data to a remote terminal server, the server water-saving irrigation management platform to do statistical analysis, output control instruction, is currently the most suitable for applications in precision agriculture irrigation of wireless communication technology.