“The quality of a hay crop is never better than when it's standing in the field,” points out Randal Taylor. “It's goes downhill from that point.”

Mechanical conditioners are the hay grower's and custom harvester's primary tool for limiting that loss, says Taylor, a Kansas State University extension ag engineer.

But too many conditioners are not properly adjusted to do the job right, he adds. They either over- or undercondition the crop, and both can have a serious impact on quality.

“Overconditioning increases baler losses while underconditioning increases your crop's exposure to potential weather damage,” he states.

Taylor, who has authored a Kansas State extension bulletin on mechanical alfalfa conditioning, identifies two basic types of conditioners currently in use: roll and tine. Most models on the market today are descendants of one of those popular designs, he says.

“You can do a pretty good job with either one, but each works best with certain applications,” says Taylor.

As freshly cut alfalfa passes between the rollers of a roll conditioner, its stems are crushed and crimped.

“When properly adjusted, this conditioner works very well with alfalfa,” says Taylor. “It does a good job on crushing the stems without damaging the leaves.”

Rollers should be set so the majority of stems are crimped every 3-4". That allows moisture to escape, reducing the drying time.

A relatively new breed of roll conditioner is called the super conditioner. It has cylindrical rubber-clad rollers that are shallowly grooved to improve feeding characteristics. Regulated pressure cracks and flattens stems without shredding or detaching leaves. In at least one study, hay dried faster than when conditioned with a conventional model.

However, Richard Koegel, an ag engineer at the U.S. Dairy Forage Research Center, Madison, WI, says this roll type does have drawbacks.

“One of the problems inherent with crushing rolls is that the forage sometimes bunches up and stops feeding, especially if you have wet, slippery material as we do in the Midwest,” says Koegel. “People have a tendency to back off on the force between the rolls so they feed a little better. Unfortunately, they may also lose the advantage of the crushing rolls.”

In tine conditioners, rotating steel or rubber fingers pick up freshly cut hay and push it against an abrasive conditioning hood. The abrasion process removes the waxy surface from alfalfa stems, allowing for faster drying.

“This type handles high flow rates well, especially for grass hay,” says Taylor.

But Koegel says the tine type's track record with alfalfa isn't as good.

“We worry about knocking off a lot of leaves,” he says.

Koegel, who has field-tested most types of mechanical conditioners, is convinced that there is little difference in performance between old and new generations of machines provided they're all in adjustment.

“The problem is that most conditioners are not run that way,” he says. “The gap between rolls is too great and people don't bother to adjust them. So they don't get the full effect of the conditioner.”

His view is supported by an Oklahoma State University survey that shows 72% of the state's hay producers use mechanical conditioners but only 39% adjust them annually.

On roll conditioners, the distance between the rolls and the force required to separate them can be adjusted. Some also have adjustments for roll speed and timing.

On tine conditioners, the rotor speed and hood clearance are adjustable. Koegel warns that with both types of conditioners, the operator should consult his user's manual before attempting to adjust the machine.

Taylor feels that one of the most commonly overlooked tasks in operating a conditioner is adjusting the system for specific field requirements. Besides adjusting to accommodate different types and quantities of forage, the operator should pay attention to when the conditioning is done.

“Crop conditions change dramatically as we move through the growing season,” says Taylor. “Typically, in the first cutting you're dealing with a lot of stems and volume. When you get to the fourth and fifth cuttings, the volume has dropped and you're getting a lot more leaves.”

Taylor says some ag engineers recommend checking a conditioner's adjustment each time it's moved into a new field.