The methods of sowing that are commonly used either place the seed on the surface of the soil or beneath the soil but near the surface. Placement of the seed on the surface is accomplished by broadcasting by hand or with the aid of such simple devices as the horn seeder or the cyclone seeder. The horn seeder consists of a bag to which is attached a metal spout. The bag is filled with seed and the operator walks back and forth across the field swinging the spout and thus distributing the seed. The cyclone seeder is similar to the horn seeder, excepting that the seed is distributed by a rapidly revolving disk. Inasmuch as broadcasting places the seed on the soil surface, some method of coverage is necessary after seeding. This is usually accomplished with a corrugated roller or by a light harrowing.
Seed can be sown and covered in the same operation by the use of seeding attachments placed on grain drills or with special grass-seeding drills. The seeding attachments on the grain drill drop the seed either in front of the disks. Unless care is taken, alfalfa may be sown too deep when a drill equipped with a grassing-seeding attachment is used. Much of the seed may drop to the bottom of the drill furrow, and this may be too deep to enable it to grow out of the ground. This is likely to happen particularly when the seedbed is loose and the wheels of the drill sink into the ground. Therefore, the better practice is to adjust the tubes of the grass-seeding attachments so that the seed is distributed back of the furrow openers of the drill. The seed which is thus sown should be covered by culti-packing or with a light harrowing.
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The corrugated roller seeder is an efficient and very satisfactory machine for sowing alfalfa. This machine consists of two corrugated rollers upon which a grass-seeding attachment is mounted. The seed is dropped immediately behind the first roller and is covered by the second roller which splits the ridges made by the first roller. Because this method assures shallow sowing in a firm seedbed, seeding rates can sometimes be reduced as much as 25 percent. However, the corrugated roller seeder is not satisfactory for use on heavier soils unless they are reasonably dry because (a) the soil will stick to the rollers and clog them, and (b) rolling heavy soils when they are wet will result in baking and crusting later.
Band seeding, a relatively new development, has given encouraging results in some areas with alfalfa and other small seeded crops. A regular grain drill can be modified for band seeding at moderate cost. This method of seeding involves placing the seed immediately over a band of fertilizer, thus promoting a more vigorous growth of the seedlings. While band seeding has not produced better results than other successful methods of seeding in some areas, it appears to be more advantageous when (a) weather conditions aren’t very favorable at planting time, and (b) soils are relatively low in fertility.