Aerators, renovators, or spiral-blade choppers, use small blades welded to heavy drums in a staggered, spiral pattern around the drum, rather than the long, longitudinally mounted blades used on conventional roller choppers. Aerators normally use two drums mounted on a frame similar to an offset disk, and they are equipped with rubber tires for transporting. Aerators are pulled by a crawler tractor or a four-wheel drive tractor with special tire protection (see Modifications for Rangeland Use). Drum diameters vary from 18 to 42 inches, and the drums can be filled with water for extra weight. Width is 12 feet, but options are available. Tractor horsepower requirements vary between 120 and 350 and depend on chopper size, weight, tree/shrub size, and type of terrain.
Aerators gained popularity in the 1990s, especially for use in brush-dominated landscapes, because of minimal vibration, effective top growth removal, soil fracturing, and the small basins formed in the soil to hold rainfall. These basins provide a good seedbed. Broadcast seeding can be conducted from a seed box attached to the rear of the chopper. Because of the rubber tires, the units are easily transported from site to site. Blade wear can be a problem, and new blades are welded in place. These choppers should not be used on rocky ground. Gravelly and some sandy soils can cause excessive blade wear. Information for use in brush control is covered in Mechanical Control.
References / Additional Information
Tilley, D.; Brazee, B.; Engle, S.; Norrie, R. 2015. Review of the Lawson Aerator for brush management. Tech Note 64. Boise, ID: USDA, Natural Resources Conservation Service. 11 p.
Wiedemann, H.T. 2007. Sculpting brush mechanically: Current state of the art. Rangelands. 29(5): 10-17.