One of Jon Orr’s dairy clients hopes to see less ash in his forage this season, in part because Orr traded his 10-year-old rake in for an H&S merger.

Orr, a custom harvester from Apple Creek, OH, is more skeptical. “I don’t know if we’ll get less ash. There are many things that contribute to it,” including the condition of the field, mower height and rake setting, he says.

“So we’re changing one of three items. Yes, the merger will put less ash in hay than the rake, but if the field’s uneven, I still have to get the merger tighter to the ground than I want to. And if the field’s uneven and they mow it too short, they’re taking ridges of dirt off ... ”

Merging can cut the amount of ash in alfalfa by 1-2 percentage points because the hay is picked up and moved over on a conveyor, says University of Wisconsin Extension forage specialist Dan Undersander.

Good overall harvest management can, too. “Disk mowers usually use angled blades that pick up downed hay a little bit better. Flat blades would pick up less dirt when the soil is dry. So a person might have to choose which is the more serious problem he has,” he says.

Although alfalfa can be cut as low as an inch without hurting yield, Undersander suggests mowing alfalfa up to 3” high to avoid picking up dirt.

Another suggestion: Make wide swaths that lie on top of stubble; with narrow swaths, hay sinks to the ground. “If you make a wide swath, then you can rake or use a merger with tines either not touching or minimally touching the ground. If you make a windrow and it’s laying on the ground, then you have to scrape the ground to get the hay up.”

Undersander reminds harvesters and their clients that grass and alfalfa plants already contain 6-8% ash, but harvesting brings that up to 12% on average. He’s seen samples testing as high as 18-19%.

“We obviously can’t put hay up without any dirt on it. But the goal would be to try to keep the ash content to less than 10%,” he says.