Abstract
Seeding depth is one of the key factors affecting rice plant growth in the current practice of the direct seeding of coated rice in the submerged paddy field. Objectives of this study are to determine optimum seeding depth of rice by theoretical analyses and to obtain information necessary for designing the seeding depth control system for the rice Seeder used in the submerged paddy field. The relationships between rice plant toppling and the mechanical behavior of the soil-plant composite system will be discussed in Part I. The boundary element method was used to model the rice plant toppling phenomena. It was concluded that a rice plant with a below ground culm length less than 0.5cm is potentially subjected to the lodging of toppling type. A theoretical analysis of the apparent buoyant phenomena of sown rice seed will be presented in Part II. These studies will provide a theoretical standard of optimum seeding depth. A seeding depth control system simulation and a related system design will be reported in the following installments.
