Are Disc Mowers Better Than Sickle Mowers?

Cost

• Mowers that cut with spinning discs are also called rotary or drum mowers. Sickle mowers have blades that move back and forth on a bar. Disc mowers cost far more than sickle mowers. A disc mower that you pull behind a tractor will cost you 20 to 30 percent more than a sickle mower. A self-propelled disc mower will cost you close to 50 percent more.

Cutting Efficiency

• You can cut more acres with a disc mower because these mowers operate at higher speeds. Disc mowers are also better for rough, thick forage or forage that is lodged or wet. Lodged means that the wind has flattened the forage or it has grown so tall that it has toppled over. Disc mowers do not become stuck or plugged, and it is easier to adjust their height. They also give a “ragged” cut. Sickle mowers cut like a pair of scissors; although they cut more slowly, they will give you a cleaner cut than disc mowers do. They cut legumes and grass well, but the blades can break on stumps and rocks. They are also apt to clog.

Tractor Power

• Your tractor should have a minimum of 30 to 45 horsepower to run a disc mower. You can run a sickle mower with a smaller tractor. Sickle bars are usually 7 to 9 feet wide. Disc mowers are smaller, at 5½ to 7 feet, but you can run them at higher speeds. You can only run sickle mowers below 6 mph. If you go too fast, the sickle bar can clog.

Maintenance and Safety

• It’s cheap and easy to replace a broken sickle blade. Disc mowers break down less often. In the past, disc mowers have been more expensive to fix, but you can change the discs easily on newer models. You have to check the discs periodically to make sure they have not become wrapped with wire that they picked up in the field. Cutting discs spinning at 3,000 rotations per minute can cut off metal stakes that you can't see in the forage or fire out rocks and objects at lethal speeds. They can also be messy because they splash juices. Some manufacturers say they should only be used if your tractor has a cab.