Highway roadside managers throughout the United States strive to maintain [a delicate balance] during each growing season.
Roadside managers must create a timely mowing schedule that ensures roadside areas remain clear of tall vegetation, without sending crews out on the road more often than needed. Mowing more than necessary can mean excess costs, increased liability and added risks for highway roadside crews, but failing to mow enough can be equally problematic - resulting in overgrown roadsides that pose a danger to drivers. Working to better manage the juggling act among vegetation control, program costs and worker safety, a growing number of states are examining the benefits of seedhead suppression programs - herbicide applications that reduce the need for mowing by suppressing the growth of plant seedheads, stunting vegetation height without negatively impacting turf appearance.
"Particularly in the eastern and southern portions of the United States, a seedhead suppression program combined with an existing mowing program can add significant value," said Dr. Fred Yelverton, extension specialist and professor of crop science at North Carolina State University. "Seedhead suppression programs reduce plant height and decrease the need for repetitive mowing, with acceptable discoloration to the turf. By managing the seedhead growth of both cool and warm-season grasses, including tall fescue and bahia grass, these types of programs can cut down on the number of times crews have to be out on the highway right-of-way."
Applied prior to seedhead development or following a mowing, a seedhead suppression program uses a low rate of herbicide to reduce the growth rate of desirable roadside vegetation. Applied in low rates, products such as Journey™ herbicide or Plateau® herbicide from BASF can help manage the growth of desirable grasses including:
- Bahia grasses, often found in Atlantic and Gulf Coast states
- Tall fescue, common across the northeast United States and Great Plains region
- Smooth brome grass, common across the Great Plains region
- Bermuda grass, found in southern states and along the Atlantic and Gulf Coasts
"For cool-season grasses, applying a single application of Plateau in the spring can help suppress seedheads throughout the spring," Yelverton said. "Mixed with a broadleaf herbicide, it can help applicators kill two birds with one stone, eliminating nuisance weeds while regulating the height of desirable plants and grasses. It's a win-win situation."
Suppressing plant height to trim costs
Using a seedhead suppression program to regulate seedhead growth on road shoulders and medians cannot only help reduce needed mowing operations within an annual cycle, but also works to:
- Improve worker safety by reducing needed mowing operations
- Free up resources, such as budget and manpower, that can be reallocated to other projects
- Reduce liability from motorists' damage claims
The accompanying table (Table I) outlines the typical average costs for mowing and applying a seedhead suppression herbicide, based on average mowing and application costs from several different departments of transportation in southern states. (Note that labour costs are significantly higher for mowing, because roadside mowing is typically a more labour-intensive process than the application of herbicide).
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Table I.
Typical Per-Mile Expenses for Mowing,
Plateau Application* (One lane mile, one-way - a one-mile long 20-foot swath, the equivalent of 2.4 acres)
Typical mowing cost (per lane mile):
labour $17.00
equipment $10.13
materials $0.87
TOTAL: $28 per lane mile
Plateau application cost (per lane mile):
labour $3.20
Plateau (3 oz. per acre) $10.40
surfactant (.25% v/v) $2.40
TOTAL: $16 per lane mile**
*Costs based on average mowing and application costs from several different departments of transportation in southern states.
**There may be a slight, incremental cost based on the price of application equipment and maintenance.
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Compared to costs of about $28 per lane mile for every single mowing treatment, each seedhead suppression application costs only around $16 per lane mile, resulting in a $12 savings per lane mile, for every unneeded mowing operation. Based on the figures from Table I, Table II examines total costs for making two annual seedhead suppression applications designed to control both warm and cool-season grasses.
In southern states, seedhead suppression applications are typically completed in the spring and fall on warm-season turf such as bahia grass and bermuda grass. In other areas, such as the north-eastern United States, roadside managers may only need to make a single application, typically in the spring, to suppress seedheads on cool-season turf such as tall fescue.
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Table II.
Typical Seedhead Suppression Costs* (Seedhead Suppression for 1,500 miles of roadside, 2 applications)
Cost per treated lane mile - $16
Lane Miles - 1,500
Total cost per treatment ¡- $24,000
Number of treatments per year ¡- 2
TOTAL ANNUAL COST - $48,000
*Costs based on average mowing and application costs from several different departments of transportation. Some southern states apply more than two seedhead suppression treatments annually, depending on climate and vegetation type. |
Numbers and benefits add up quickly
While actual mowing and seedhead suppression costs generally vary from region to region, the simple fact that seedhead suppression programs help reduce the number of mowing operations generally creates significant overall benefits for roadside managers - regardless of region or growing cycle. Consider, for example, the fact that the total cost for a single seedhead suppression herbicide treatment is around $1,600 for every 100 lane miles. In comparison, the average cost to repair a single mower deck stands at nearly $2,100, according to industry research. Similarly, the average cost to settle a motorist's damage claim from a rock thrown by a mower stands at around $5,400.
"Obviously anything you can do to keep crews and mowers off roadsides is going to have a beneficial impact for your operation," Yelverton said. "It helps reduce liability, improve worker safety and control your overall maintenance costs."
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Table III.
Annual mowing costs, with no seedhead suppression* (1,500 lane miles , one-way)
Cost per treated lane mile - $28
Lane miles - 1,500
Total cost per treatment - $42,000
Number of treatments per year - 5
TOTAL ANNUAL COST - $210,000
*Costs and mowing cycles based on average costs from several different departments of transportation in southern states. |
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Table IV.
Annual Mowing Costs, with Seedhead Suppression* (1,500 lane miles , one-way)
Annual Mowing Cost
(3 mowing operations) $126,000
Seedhead Suppression Costs (2 Plateau® herbicide applications) $48,000
TOTAL COST: $174,000
*Costs and mowing cycles based on average costs from several different departments of transportation in southern states. |
As highlighted in Tables III and IV, the typical total annual costs for using mowing alone to control roadside vegetation is significantly higher than a program that combines mowing with a seedhead suppression program. Depending on the number of lane miles under management, such savings can add up over a relatively short period of time.
"If you already apply herbicide to control undesirable broadleaf weeds, adding a product that can provide seedhead suppression makes even more sense," Yelverton said. "At the same time you're working to control broadleaf weeds, why not mix in a seedhead suppression product to improve cost-savings and reduce the height of grass? For an extra few dollars per lane mile, the long-term savings add up pretty quickly."
The theoretical example in Table V highlights the dramatic differences between a yearly mowing-only program and a mowing program combined with herbicide applications. Over just 1,500 lane miles, using seedhead suppression combined with mowing has the potential to create an estimated $36,000 in savings.
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Table V.
Mowing Alone vs. Mowing with Seedhead Suppression
$210,000 Annual cost for 5 mowing operations
$174,000 Annual cost for 3 mowing operations + 2 herbicide applications
$36,000 TOTAL SAVINGS from Seedhead Suppression |
Using Plateau in Roadside Seedhead Suppression Efforts In implementing a seedhead suppression program, transportation departments in states nationwide are turning to Plateau for effective, long-term control. Using a recommended rate of 3 to 4 ounces per acre of Plateau, combined with surfactant at a rate of 0.25% v/v, applicators can achieve a number of key benefits for suppressing seedheads in roadside areas.
Specifically compared to other common herbicides used in roadside areas, at higher rates Plateau will provide key benefits including:
- Excellent control of perennials like Johnson grass, dallis grass and vasey grass when applied at higher rates or accompanied by a tank mix partner.
- Preemergent and postemergent control of troublesome annual weeds.
- Greater safety to common bermuda grass, bahia grass and tall fescue compared to other herbicides commonly used for seedhead suppression, such as Roundup® with MSMA or Oust®.
- Less unsightly brownout, which can draw unnecessary attention to treated sites?
- High activity at low use rates, with a recommended rate of just 3 to 4 ounces of Plateau per acre.
- Low impact on the environment, because Plateau affects an enzyme found only in plants, not in humans, animals or insects.
For more information on using Plateau or Journey as part of an effective seedhead suppression program, contact your nearest BASF ProVM sales specialist at 1-800-545-9525, or visit www.vmanswers.com.
Always read and follow label directions. Plateau is a registered trademark and Journey is a trademark of BASF. Roundup is a registered trademark of Monsanto Company. Oust is a registered trademark of E.I. du Pont de Nemours and Company.
Source: ©2005 BASF Corporation. All rights reserved.
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