In Nanki, Mie Prefecture, Japan, the mulching and drip irrigation system produces high-quality fruit despite large variations in the weather. For this cultivation system, we developed a small, stationary agricultural robot, "Field Server", which measures environmental and growing conditions in real time in the orchard. Our goals were to solve the problem of loss of the skills developed by experienced farmers due to a lack of new agricultural workers and aging of farmers, and to cultivate mandarin oranges with the required quality under occasionally severe and highly variable climate conditions. In this research, we demonstrated the ability of Field Server to monitor the agro-environmental conditions that affect plant physiology and the farmer's attitude towards their work and demonstrated the eKo wireless sensor network that was designed for agricultural use. To accomplish our goals, we installed a sensor network to support long-term, stable operation, including optimal placement of sensor nodes, optimal installation of the sensors and modification of network connections with Internet, and developed user-friendly Field Server and eKo data browsing software to help agricultural workers. Long-term data acquisition for a 1-ha agricultural site became possible due to improvements of the eKo system's hardware and software. In addition, the development of databases and related software permitted comparisons of the acquired data with data obtained from nearby AMeDAS stations. The comparison revealed the importance of agro-environmental monitoring (especially for rainfall) close to the production area and of soil moisture measurement to guide irrigation and produce high-quality mandarin oranges.
