Shibusawa Sakae
Graduate School of Agriculture, Tokyo University of Agriculture and Technology

Community-based precision agriculture involves a management strategy for both cropping technology and organization of farmers. A key issue has been the decision-making process when the precision agriculture is applied. The paper will focus on the thinking process with technology packages as example.
In simulating expert farmers’ practice, five factors of farming system and eleven units of thinking process were derived. The five factors are crop, field, technology, constraints and motivation, which have already been introduced when proposed a model of community-based precision agriculture as a Japanese model. The eleven units, a new idea of analyzing farmer’s decision process, will be discussed with farm practice such as weed management.
A case study was done on the combination of the real-time soil spectrophotometer (RTSS) and a combine harvester with a yield monitor, followed by a system of field maps. The assumption was nitrogen balance for the evaluation of missing nitrogen as evidence of environmental impacts. A recommendation was derived from the context using yield map, protein map and missing nitrogen map, accompanied with farmer’s motivation.
A new trial undergoing is a site-specific irrigation management aiming to meet the need of plant growth by using a precise control technique for water resources in the rooting zone, followed by high efficiency uses of agricultural water. The system involves various technologies including precise monitoring of water content in the rooting zone, on-line real-time precision irrigation, using differences in soil water resources, re-using and recycling of water resources, and identification of soil water parameters to describe the crop needs for water, towards the development of an energy-efficient and water-saving plant factory system. The problem is how to define the water need of plant, which will depend on the growers’ motivation.
Key Words: thinking process, community communication, technology package, water saving