Land consolidation involving the joining of small paddy fields to form a large-size field has been promoted recently in Japan in order to increase the efficiency of rice production. However, the variability in soil fertility within a large-size field causes problems for rice production such as late heading, lodging, and deterioration of rice quality. To address these problems, a site-specific nitrogen management system for paddy rice was developed. In this paper, we briefly review the concept and the achievement of precision agriculture, outline the site-specific management system which we developed, and present the results of the application of this system in a farmer’s field.