In recent years, with the progressing R&D and commercialization, sensor networks are increasingly being used in paddy fields. Hereafter, to increase their uptake on Japanese rice farms, it is necessary to reduce the costs of installation and operation. Large-scale rice management can use several hundred sensors, and costs of data communication may constrain their adoption. No prior studies found to have investigated the operation of large-scale wireless sensor networks in paddy fields with hundreds of nodes. In this study, we measured the power consumption of a full-mesh wireless sensor network in operating paddy fields and predicted the operating duration. Tuning the network communication parameters improved the electricity saving effect and greatly extended the operating duration. We hereby presented basic knowledge that will contribute to understanding the operation of sensor network in large-scale paddy fields.

Beef cattle numbers in Japan are decreasing with the loss of farmers. Improvement of productivity is necessary to allow the remaining farmers to stabilize cattle production and management. The calving-to-conception interval, which has increased in recent years, must be reduced. We made a system dynamics model to evaluate the improvement of productivity by reducing the calving-to-conception interval. The model focuses on the growing stage and sets an upper limit to the number of cows. Our simulation reduced the interval from calving to first service from the default 80 days to 60 or 70 days, and the number of artificial inseminations from the default 1.6 to 1.0 or 1.3. For every 1 day reduction of the calving-to-conception interval, a farm with 100 head of cattle would increase the annual number of calves by 0.23, increasing its profit by 128,000 JPY.

Examples of drone use in agriculture are increasing, along with accidents. In particular, crashes and contact by drones may cause serious damage. To avoid accidents caused by propellers, we moved the propellers inside the drone and used the Coandă effect to produce thrust. The purpose of this research was to optimize thrust. Design optimization involves multiple design and objective variables, and the resultant enormous number of combinations creates substantial calculation costs of fluid simulation for the performance evaluation of just one design candidate. We propose an effective design method based on a self-organizing map to evaluate and visualize a relatively small number of design candidates from which the optimum candidate can be selected. We created 108 design candidates in 3D CAD software (Autodesk Inventor) and evaluated the propulsive force required for flight with 6 design variables in the propulsion mechanism in a fluid simulator (Autodesk CFD). We set objective variables of propulsive power and weight and visualized them by use of the self-organizing map. The evaluation index of the optimized candidates was about 7% better than basis.