In the rest of Ontario, there has been no difference among sources or application methods. Anhydrous ammonia must be placed under the soil deeply enough to prevent it from escaping into the air. The slot is then covered with soil. If anhydrous ammonia is knifed into soil that is too wet, hard or cloddy to seal properly, a large proportion of it can be lost. Equipment is also available to allow application of anhydrous ammonia using a disk or cultivator.
Ammonia is a clear, colourless gas.
When it vaporizes, however, the low temperature causes water vapour in the air to condense to fog. Because a small amount of ammonia can cause the condensation of a relatively large amount of vapour, ammonia losses usually appear worse than they actually are. For example, it has been estimated that 2 ounces of ammonia can produce 13 gallons of mist. Ammonia is toxic to plants. To prevent damage to germinating seeds or seedlings, preplant ammonia should be applied at least 10 cm deep, with the seed being planted no more than 4 cm deep.