Leaving swaths instead of windrows is the easiest and most effective way to reduce hay drying time, points out Kevin Shinners, University of Wisconsin ag engineer.

Shinners' studies have shown that laying alfalfa in swaths (70% of cutting width) reduces drying time by 25-40% compared with laying it in windrows (about 45% of cutting width).

“This can be a reduction in drying rate of up to six hours under typical Wisconsin weather during second cutting,” he says.

Most conditioning rolls are less than 9' wide, so the widest swath that can be laid by most mower-conditioners and windrowers is about 8'. Going to wider cutting equipment lengthens drying time because it results in denser swaths.

“A very rough rule of thumb is that, for every 1½' of cut width beyond 9', you'll experience an increase in drying time to baling moisture of about one hour,” says Shinners.