Some airline passengers choose to pack all of their belongings in a carry-on suitcase to maximize space and avoid paying for checked baggage. Likewise, some hay producers apply the same logic when making high-density bales to improve baling efficiency and save money in the long run.
In addition to baling, farmers bear the cost of collecting, transporting, storing and feeding the hay and straw. Kevin Shinners, professor emeritus in the Department of Biological Systems Engineering at the University of Wisconsin-Madison, notes that these rates are influenced by the number and weight of bales handled, which depend on the type of equipment used.
Since the invention of the large square baler more than 40 years ago, manufacturers have developed both wide-density and high-density balers. The latter has been designed to maximize the convergence and length of the bale chamber, giving it more back pressure and compression force than conventional machines.
Shinners says greater compression force requires a larger gearbox, stronger piston, and stronger transmission and frame, which is why high-density balers command such high retail prices. Even so, these balers will reduce the number of 3×4 size bales made by 32% compared to a conventional baler of the same size. This reduces the cost of producing and distributing hay.
To comply with haul weight restrictions and legal trailer dimensions, engineers have found that the optimum bale density is 15 pounds per cubic foot. Although this may not be an issue for some forages, other species may need to be baled at a higher density to meet the criterion.
“Consider the crops you bale,” says Shinner. “Density goals can often be achieved when baling alfalfa with an extended-density baler, but if straw is an important crop to bale, high-density balers could be economically viable.”
Even if the purchase of a high density baler is justified, these machines can be up to 50% more expensive than conventional machines. They also require a high horsepower tractor to operate, and the bales must be secured with twine which has extra tensile strength. Also, forage moisture should be carefully monitored before baling to ensure that the hay is not too wet.
“It’s recommended that the humidity be below 18% – and ideally below 16% – when hay or straw is packed in large bales,” says Shinners. “This goal is particularly important in high density bales because these heavier bales have more substrate to support microbial activity and heating.”
Applying propionic acid to hay before it is baled can further reduce the risk of spoilage and spontaneous combustion. In summary, maintaining forage quality will promote faster return on investment in a high-density baler.