The rice transplanter is included in the list of 100 Postwar Japanese Innovations which helped to fuel Japan's economic growth. Practical application of rice transplanters began in the early 1960s. Its work efficiency has improved dramatically when the manual-driven transplanter was improved to a power-driven transplanter, and from a walking type to a riding type transplanter. In the period of 20-30 years since the introduction of rice transplanters, manual transplanting by hand which requires hard work has almost disappeared and rice transplanters are now widely used in most paddy fields.
Although rice transplanter is an important innovation, rice cultivation without using transplanter is also another advancement in agriculture. Even with the current progress in farming mechanisation, seed germination and transplanting of seedlings are still labor intensive tasks. Hence, there are high expectations for direct sowing techniques which totally eliminates the transplanting of seedlings. The National Agriculture and Food Research Organization has developed many direct sowing technologies which are rapidly becoming popular.
Dry field direct seeding of paddy rice using grain drill
Seeding operation by grain drill
In a large dry paddy field, rice seeds are sown with large sowing machine known as grain drill for upland field, and water is supplied after germination and seedling development. Significant labor saving and cost reduction are possible as the efforts for rice planting and nursing are not required. Since the sowing machine can also be used for wheat and soybean cultivation, it is suitable for crop rotation management of these crops. A video of seeding operation by grain drill is available here (in Japanese only).
Iron coating of seeds for direct seeding in submerged paddy fields
Sowing operation by unmanned helicopter
Iron coating of seeds has been found to be effective strategy for direct seeding in submerged paddy fields. It is a technique to sow seeds coated with iron powder in submerged paddy fields using various sowing machines can be used. Seeds coated with iron powder are heavy, hence floating seedlings are less likely to occur, and damage by birds is also less. Since there is no need for nursery and rice planting, the working hours of spring will be reduced. Also, in combination with the use of transplanters, harvesting work burden in the autumn can be alleviated. A video of iron coating of seeds for direct seeding in submerged paddy fields is available here (in Japanese only).