We configured a guidance system on a sprayer using a low-cost GNSS (Global Navigation Satellite System) receiver and a tablet computer onto which guidance software had been installed. Assuming herbicide application after rice seeding, we evaluated the driving accuracy when non-skilled and skilled operators drove a sprayer, using a GNSS guidance system, employing targets in the field or relying on visual inspection. Using targets gave the highest precision. When the skilled and non-skilled operators drove the sprayer with the guidance system using a single frequency RTKGNSS receiver, RMS of lateral deviation from desired path were 0.26 m and 0.27 m. Use of the GNSS guidance system raised non-skilled operators to a level comparable to that of skilled operators.

A grain conveyor structure was developed to reduce the time required for cleaning the inside of a combine harvester. In the developed structure, the horizontal plane parts in the grain conveyor were slanted to promote slipping of grains. Further, the cleaning ports were enlarged and located in optimized positions to enable the easy discharge of grain residue. The results of examinations conducted using a head-feeding combine harvester indicated that the time required for grain removal in grain conveyors with the developed structure was approximately half of that required with the conventional structure.