Transplanting, a highly labor-intensive and costly method, can be substituted by direct seeding, which could reduce labor needs by more than 20%. Rice is either dry-seeded on well-prepared, dry/moist soil or wet-seeded on puddled soil. Current direct seeder models drill seeds continuously at a seed rate higher than recommended and without consideration of desired seed-to-seed spacing. As the seed drum is emptied, the seeding rate increases steadily and steeply at the end and uniformity in seeding rate is not maintained. Hence, an improved direct-rice seeder that uniformly distributes seeds will be more useful in maintaining a uniform plant population in the field.
A test rig was developed and the influence of the machine and operational parameters — drum shape, drum diameter, number of seed-metering holes, diameter of seed-metering holes, and forward speed of operation — on the seeding rate of the drum seeder were investigated under laboratory conditions. Optimum results were obtained with a hyperboloid drum 200 mm in diameter with nine seed-metering holes each 10 mm in diameter, and a forward speed of 1.0 kph.