Evolution of Roadside Management in Iowa
Shortly after the close of the 19th century, Iowa’s rural roads underwent a transformation. An ambitious “Get Iowa Out of the Mud” campaign launched in the 1920’s was the impetus for modification of secondary roads from narrow, muddy trails to the all-weather routes we enjoy today.
Roads were raised, graded and surfaced with crushed rock or gravel to accommodate a steadily increasing flow of motorized vehicles. Ditches on either side allowed water to drain from roads as well as from adjacent lands.
Reconstructed roadsides were seeded with plant materials readily available at that time including smooth brome, Kentucky bluegrass, alfalfa and redtop. Brome was extensively used because of its availability and adaptability. Brome monocultures, however, proved to be limited in their ability to compete with persistent weed species such as Canada thistle.
To battle noxious weed problems, counties began ambitious spraying programs in the 1950's taking advantage of the recent introduction of chemical herbicides. Typically, all or a significant fraction, of a county’s roadsides were “blanket” sprayed yearly. A non-selective approach, the objective of blanket spraying was to treat all areas of selected roadsides, with little regard to whether problem weed species were present. Blanket spraying had several advantages. It did not require applicators to identify weed species and did achieve a modicum of success in terms of short-term (single season) weed control. However, weed patches persisted in the same areas year after year and some began to question the effectiveness of this costly procedure.
Graduate students under the direction of Dr. Ackmann at Iowa State University conducted studies of native grass use in state roadside plantings in the 1940’s and 50’s. In the late 1960’s, Dr. Roger Landers – then an associate professor of botany and plant pathology at Iowa State University – began experimenting with the use of native grasses for weed control in roadsides. Results from his trials and other research have demonstrated the value of these plants - not only for weed control - but also for erosion control, wildlife habitat and aesthetic appeal. Studies conducted in 1971 by Dr. Paul Christensen and David Lyon on Linn County roadsides, yielded results supporting the practice of spot, rather than blanket, spraying and the use of native grasses and wildflowers in roadside planting projects.
Fourteen years later, in 1985, the Mitchell County Conservation Board began a program of planting switchgrass into roadsides disturbed by grading or cleaning operations. In 1986, Blackhawk County appointed a conservation employee as weed commissioner, included roadside vegetation management duties as part of the job description and effectively created Iowa’s first roadside biologist. A roadside inventory recently completed in Blackhawk County by a University of Northern Iowa graduate student provided a ready source of information for the new program and enhanced its ability to manage roadsides in a manner which preserved existing prairie remnants and promoted the use of native vegetation in plantings. Blackhawk County also developed a program of weed control in their roadsides utilizing mechanical, chemical and cultural techniques – an “integrated” approach.
Since the mid 1980’s, approximately one-third of Iowa’s counties have hired roadside biologists and most other counties have adopted some practices and procedures of Integrated Roadside Vegetation Management (IRVM). Establishment of the Roadside Office at the University of Northern Iowa in 1988 and Living Roadway Trust Fund in 1989 provided invaluable support to the fledgling IRVM program. In 1989, the Iowa Legislature passed the Integrated Roadside Vegetation Management Law mandating certain IRVM practices on state rights-of-way.