A Review of Iron‐Coating Technology to Stabilize Rice Direct Seeding onto Puddled Soil

Abstract

Core Ideas The innovation of rice direct seeding with Fe‐coated seeds was analyzed. The Fe‐coated seeds were prepared through the oxidation of reduced Fe on husks. The high‐density Fe‐coated seeds are resistant to birds and seed‐borne diseases. Iron‐coated seeds exhibit improved anchorage in water seeding in puddled fields. Transplanting is a widely practiced traditional plant establishment method for rice (Oryza sativa L.) production in Asia. To reduce costs, there is a desire to change the method from transplanting to direct seeding. Problems associated with this management change include inconsistent seedling establishment and heavy weed infestation. Because puddling in flooded soil, which is a common land preparation in transplanting, destroys the soil structure and smooths the surface, directly seeded seeds float and fail to anchor. This paper analyzes the development of high‐density Fe‐coated seeds and the procedure of water seeding these seeds onto puddled soil. Pre‐germinated seeds were granulated using a mixture of reduced Fe powder and calcined gypsum. The Fe powder on the seed surface was oxidized, producing rust, which serves as a binder for the formation of a hard coating layer. The dried Fe‐coated seeds could be prepared manually or mechanically in large quantities and stored for more than 1 yr at room temperature. The seeds are characterized as resistant to sparrow attack and seed‐borne diseases and are seeded onto the puddled soil surface by broadcasting, row seeding, or hill seeding. In addition, the coated seeds could be successfully seeded onto non‐puddled soils using the water seeding or dry seeding methods. This technology could be applied to rice production worldwide following further study.