Preservatives and inoculants are products to minimize problems that occur between cutting alfalfa and getting hay in the barn. These products are designed to reduce the amount of time from cutting to baling without increasing the risk of spoilage. Each type of product works in a different way.   

PRESERVATIVES, such as buffered propionic acid, are applied just in front of the baler. They allow hay to be baled at 20% moisture or more. Watch out at moisture contents approaching 30%! When preservatives work well (at high rates of the product with large volumes of water), moist hay can cure out and store well. They are costly and slow the baling operation because of hauling the water. Preservatives are profitable when baling high moisture hay when rain is imminent.   

INOCULANTS usually consist of bacteria or enzymes that creates an environment in the bale that stop growth of hay-rotting bacteria and molds. Recent products apparently work well with moisture contents about 20%. They are relatively inexpensive and can offer some protection from excessive heating immediately following baling.   

NOTE: A well-adjusted crimper (conditioner) that breaks stems every 1-2 inches is the hay producer's best friend. Crimping costs very little and can drastically reduce drying time.