 | This article is rated Stub-class on Wikipedia's content assessment scale. It is of interest to the following WikiProjects: | ||||||||||
| |||||||||||
Untitled edit
The stub is not entirely accurate. This is just discussion, so I'm not going to try to write it in Wikipedia style, but let me lay out the types of seeders.
Broadcast seeding is used for hay and turf crops. Grains can also be sown by broadcasting.
A drill is typically used for grain crops, where closely spaced rows (several inches apart) have seeds dropped into them at an average rate of so many per foot of linear row. The seeds flow through an adjustable valve or aperture from a bin, but they are not placed individually.
A corn planter (not a precision seeder, although the stub implies that it is) is used for corn, soybeans, and other large seeds. It meters the seeds one at a time, but then it drops the metered seed through a chute, and there's some rattling about. The result is plants that are--on average--evenly spaced in the row; but there is some jiggle. This is acceptable, because the crop plants tend to be large and robust, so cultivation only has to come close to the plant, not right up against it, when the plants are young. The crop will quickly outgrow small weeds that are in tight to the row and will shade them out.
A precision seeder, on the other hand, virtually lays the individual seed in place. Precision seeding is used for small seeds and tightly spaced plants. As an example, a grower can sow a beet seed every 2 inches--or every 1.25 inches, or every 2.5 inches, or any other desired spacing. In the case of carrots, it's possible (I've done it) to sow a triple row, with the total width four inches and the seeds staggered so that the two outer rows are spaced every 1.25 inches and the inner row is spaced every 1.5 inches (it's competing with the two outer rows for water and light, so it can't support the same close spacing).
The way a precision seeder is able to do this with such fine-seeded crops as carrots is through the use of sized, coated seed. Coated seed is seed that is bulked up with a soluble coating to precise dimensions that just fit the seeder aperture. Sized seed is seed that is sorted by size range before sale. One type of precision seeder uses interchangeable rubber belts that are punched to the pattern needed for a particular size seed and a particular spacing.