No abstract

In this study the operational speed of screw based pick and place mechanism was compared with that of a crank-rocker based pick and place mechanism analytically for the design of a seeding machine for system of rice intensification (SRI) seedling tray. The configurations of the two types of mechanisms were generated based on their positions relative to a seedling tray conveyor, seed container and size of seeding manifold. The screw based mechanism consists of a vertical screw to which the seeding manifold was mounted and a horizontal screw to which the vertical mechanism was mounted. The vertical screw bearing the seeding manifold reciprocates down to pick seeds from seed container and back to the initial position. The horizontal screw translates horizontally to deliver the vertical screw bearing the seeding manifold to the seedling tray on the conveyor. The crank-rocker based mechanism consists of a pair of crank-rocker carrying a seeding manifold in between them. The mechanism rotates clock wise to pick seed and counter clock wise to drop the seed on the seedling tray. The time required for a complete pick and place circle was computed for both mechanisms using basic mechanics principles. Crank-rocker mechanism with a theoretical pick and place period of 1 second was found to be better than the screw based mechanism with 78.8 second per pick and place circle.

One of the challenges faced by farmers in adopting the system of rice intensification is the seed establishment required high labor demand. This research aims at providing an alternative to seedling transplanting for the system of rice intensification. In this research the paddy seed was enhanced with the use of pharmaceutical capsule as a seed coating material for ease of seed singulation and suitability in handling by a conventional direct seeding technique. It covers the study of capsules as a suitable paddy seed coating material. The solubility of starch and gelatin capsules in water was studied at three different temperatures of 25oC, 35oC, and 45oC. Three paddy seed treatments of dry seeds, primed seed, and pre germinated were each placed in to the capsule at the ratio of 1:1 and planted in the soil with three replications. The planted seeds were irrigated two times daily for a period of 10 days within which the germination and emergence were recorded on daily bases. Gelatin capsule was found to be soluble in water at temperature of 45oC and above. Starch capsule on the other hand was found to be soluble at temperatures of 25oC which made it the more suitable paddy coating material in comparison with the gelatin capsule. The germination and emergence results of starch capsule coated paddy were found to be 95%, 83%, and 58% for the pre germinated, primed, and dry paddy seeds respectively.