ORAL - International Conference of Agricultural Engineering

Additionally, modification of the software for Field Server data that indicates latest sensorvalue and image and past data stored in the database was implemented. Furthermore, thedata acquired by each sensor node was organized to satisfy various requirements and webpages that provide graphic representations and display the latest sensor value weredeveloped. In detail, the data collected by weather station was packed as agrometeorologicaldata, and data measured by each soil moisture sensor and precipitation obtained by weatherstation were packed for the purpose of supporting irrigation management.3. Results and Discussion3.1. Sensor Nodes Allocation and Data Acquisition ProgramIt was decided to set up sensor nodes at three critical points where it becomes an irrigationindex for cultivation management, and the points were selected according to the soilmoisture distribution map based on the research on TDR soil moisture measurements oforchards shown in Fig.4(a) (Fujita et al., 2011). Fig. 4(b) shows the installation of sensornodes at mandarin orange farm at Kanayama Pilot in Kumano city, Mie-pref. Japan (N:33°51’ 47.97’’, E: 136°03’ 23.29’’) (Togami et al., 2011a). Considering the sufficient capabilityof communication range, the base radio and sensor nodes were placed about 3 m aboveground which is higher than mandarin orange trees. Four nodes were placed at the points asis described shown in Fig. 4(b). We implemented the construction of sensor network for longtermand stable operation including the optimum placement of sensor nodes, the optimuminstallation of sensors and the modification of the gateway. In the experiment, it was shownthat four sensor nodes were able to cover the area of about 1 ha with stable communications.(a) Soil Moisture Distribution Map(b) Allocation of Field Server andSensor NetworkFIGURE 4: Mandarin orange farm at Kanayama Pilot (N: 33°51’ 47.97’’, E: 136°03’ 23.29’’)The developed program of eKo data acquisition enabled to minimize data loss, which is,even if the master server breaks down, the data stored in the slave server remains. Moreover,internet security problem was alleviated because of the application of the Linux box andgeneral operating system. Furthermore, accessibility to the data and data-handling wereimproved due to the construction of the database server. In addition, the construction of the