Device Makes Quick Work of Cotton Cleanup Chore

A new device creates big savings of energy and time by simplifying a tedious but crucial cotton field chore called the "plowdown."

After harvesting cotton's fluffy white bolls, growers sever the roots and plow the plants under. Otherwise, the plants re-grow the following year--just when emerging pink bollworm moths are hunting for a home. The pests are among cotton's worst enemies.

Conventional plowdown equipment requires several steps to shred and bury the 2- to 6-foot- high cotton stalks. Scientists with the Agricultural Research Service are testing a tractor- mounted alternative. It neatly buries whole stalks, compressing them into a continuous "rope" about 6 inches thick.

The new device reduces tractor passes from seven to only one or two. The result: an estimated 70 percent energy savings, according to ARS agricultural engineer Lyle M. Carter. In addition, the device reduces soil compaction that thwarts root growth and limits the plant's ability to absorb moisture and nutrients.

Carter is conducting the experiments at the ARS Western Integrated Cropping Systems Research Unit, Shafter, Calif. Tests by Carter and the device's inventors--Gary W. Thacker of Pegasus Machinery Company, Tucson, Arizona, and Wayne E. Coates of the University of Arizona--have shown cotton yields from sites cleared with the device are equal to those of conventionally cleared fields.

The scientists are now confirming that their approach controls the pink bollworm, and are ensuring that the tactic doesn't increase the incidence of soil-borne diseases.

The researchers also want to determine whether the method prolongs the availability of organic material as food for beneficial, soil-dwelling microorganisms. The helpful microorganisms enrich soils in cotton-growing regions of the arid West. The hoped-for improvement in the microorganisms' food supply could happen if buried stalks take longer to decompose than conventionally shredded stalks.

The ARS tests are being done under a three-year cooperative research and development agreement with Pegasus.

Scientific contact: Lyle M. Carter, USDA-ARS Western Integrated Cropping Systems Research Unit, 17053 Shafter Ave., Shafter, CA 93263, phone (805) 746-8004, fax (805) 746-1619, lcarter@lightspeed.net.