Selecting the proper seeder setup to effectively meter a given seed lot can be very difficult for a vegetable grower, especially if the seed lot is not graded for size uniformity. A belt-type seeder should be able to effectively singulate the seeds if the seeds are spherical and uniform because the holes are specifically sized. Seeds that are not graded for size uniformity may not be singulated effectively by a belt-type seeder. A vacuum-type seeder should be able to uniformly meter a wider range of seed sizes better than a belt-type seeder since the holes in the seed plate must only be smaller than the smallest seeds in the lot. Seed lots (graded and ungraded) of two cultivars of turnip (Brassica rape L. Rapifera group) were metered with a belt seeder using belts with holes 6/64 inch (2.4 mm) or 7/64 inch (2.8 mm) in diameter or with a vacuum seeder. Neither the belt nor vacuum seeder resulted in satisfactory singulation with any of the seed lots. With the larger [7/64 inch (2.8 mm)] belt holes, there were excessive incidences of multiple seeds per drop. With the smaller [6/64 inch (2.4 mm)] belt holes, multiple drops and missed seed were both excessive. The vacuum seeder also resulted in excessive misses and multiples.
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