To calculate how many pounds of ammonia will be needed, multiply the number of bales in the stack by the average bale weight and then multiply by 0.03. Order an anhydrous ammonia nurse tank with that many pounds of ammonia. For very large stacks, several tanks may be necessary. After the tank is empty disconnect it from the application pipes and allow the forage to remain covered for at least 3 weeks. The reaction between ammonia and fiber is dependent on temperature, so if forages are treated with ammonia during cold weather a 5 week treatment period should be used.
Forage can remain covered for longer periods without problems.
The hay should be uncovered carefully so that the plastic can be reused which reduces treatment cost considerably. Some people recommend that the forage be left uncovered for 3 to 5 days prior to feeding to allow free ammonia to escape. This generally is not necessary, but sometimes animal acceptance may be poor initially if ammoniated bales are not aired out prior to feeding. Anhydrous ammonia is a toxic gas. Proper ammonia safety precautions must be followed.