Selecting the proper seeder setup to meter a given seed lot effectively can be very difficult for a vegetable grower, especially if the seed lot is not graded for size uniformity. A belt-type seeder should 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 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 turnip (Brassica rapa L. rapifera group) cultivars 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 satisfactorily singulated any of the seed lots. With the larger (7/64 inch) belt holes, there were excessive incidences of multiple seeds per drop. With the smaller (6/64 inch) belt holes, multiple drops and missed seed were excessive. The vacuum seeder also resulted in excessive misses and multiples.
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