One of the advantages of using an air seeder over another type of planting equipment is that an air seeder volumetrically meters the product right below each tank. Traditional planters singulate seeds right above the row. Depending on your needs, using a conventional planter to complete work out in the field can take longer.
An air seeder uses fans to blow air through its primary tubes. While the air is blowing, the meter is turning, dropping seeds at regular intervals into the airflow, and taking it down to the tool. There are air seeders which carry both seeds and fertilizer, or seed-only air seeders.
Many typical air seeders deliver both seeds and fertilizer. In the case of combination models, primary hoses carry both seed and fertilizer to the tower. In the tower, the mix of fertilizer and seed is distributed into secondary hoses and passed down to the openers. The opener blade opens up the soil, using a gauge wheel to define the depth at which the seed should be placed. The dropped seed and fertilizer is placed at the bottom of the trench created by the blade, and a pressing wheel will usually push the seed into the soil to ensure full contact.
Air seeders work best with smaller seeds, typically seeds that are round and small such as maize. While they often combine the spread of fertilizer with seed distribution, they can be less versatile than traditional planters as there are restrictions based on seed type. Air seeders are also often larger than other planters, so storage and transport of equipment can be a little more tricky.