Oman is a country with a total area of 309,500 km². However, cultivable land in Oman is estimated to be less than 2%, which amounts to about 6100 km². More than 50 percent of the arable lands located in the northern coastal belt of Al Batinah region. The country with average annual rainfall around 100 mm, has limited natural fresh water resources and has been facing the serious problem of sea water intrusion into the scarce groundwater reserves due to undisciplined excessive pumping of groundwater for irrigation. Accomplishing this task, intelligent Energy & Water Meters were installed in selected farms to monitor and allocate groundwater quota and ensure sustainability of farming through controlled irrigation.

 

In order to implement this, it was decided to control/monitor groundwater pumping, while monitoring several field parameters such as soil moisture, EC and temperature. Since the farmlands are spread over the whole Batinah region of near 200 km stretch, it was decided to install the monitoring system in 40 farms with varying levels of control. This required remote monitoring of data, transmission of data and control commands to and from the remote stations to a central server computer, in order to make near real-time decisions based on the data and crop water requirement models to ensure safe pumping of ground water. It was also decided to implement sensor-based irrigation control instead of ET-based control systems for more precision.  

 

The irrigation control system was designed around the PIC-182455 microcontroller and short range radio links based on Zigbee communication protocol. Each field module was planned to consist of a microcontroller programmed to access the sensors and acquire data, which will be transmitted to a central module that acts as the coordinator or the main node for the particular farm. The main node will transmit data to the server computer encapsulated as an SMS, over the cellular network.  In order to achieve better reliability in operations, the database part of the project was made independent of the real time decisions taken to control the actuators by utilizing part of the intelligence of the microcontrollers.  It was decided to program them to handle day to day measurements and take on-farm decisions based on the measured values and the model predicted values. In order to achieve this, it was necessary to derive model predicted values for the particular crop pattern in a particular farm and convert them to a look up table that can be fed to the on-board memory of the microcontroller device.  The data collection environment was designed to be in MS Excel, while a GUI will be developed in MS Visual Basic to handle the communication and data transfer between the coordinator modules and the main server.