Cover Story: Road Salts - the silent enemy that can stunt your crops

Tuesday, August 4, 2009

Under environmental law, road authorities are exempt from investigation and from penalties for damage related to salt. Yet road salt leaching into fields can cause havoc with crops, as a Dunnville strawberry farmer found to his cost

by MARY BAXTER

Salt is a key ingredient in the recipe for making sauerkraut. It's packed around cabbage to draw out water. That same pickling principle, at work in Ray and Laurie Korten's strawberry field near Dunnville, is a recipe for disaster.

In late May, the field, sloping towards the Grand River, resembled a drought zone. The plants that emerged were flowering but only a fraction of the size of the picture-perfect stand across the farm's lane. Elsewhere in the field, crystallized salt glinted on the bare earth, reflecting the rays of a penetrating spring sun. Some areas were so contaminated that even the weeds weren't growing.

Ray Korten says that he and Laurie knew there was a problem spot of about five acres in the field, which at one time had been used to grow hay and corn, but they didn't realize the extent until they expanded their strawberry crop. By the time the June 2008 harvest rolled around, berries from strawberries planted the year before were "just the size of pennies," he says. Many of the plants added in the spring just didn't grow.

Ray blames the contamination on road salts routinely applied at a highway intersection adjacent to his property and a clogged drainage ditch which leaked runoff water into his field. Samples of the ditch water indicated a sodium count of 278.55 parts per million (ppm).

Keith Reid, the province's Stratford-based soil fertility expert, says that salt contamination of soil is "pretty uncommon" in Ontario. But Drew Thompson and Owen Gifford, agronomists with Niagara-based Clark Agri Service, say the problem may be more widespread. "I know of numerous spots (in eastern Ontario) where you'd get maybe a quarter to a third of an acre where essentially nothing grew because of the road salt ponding," says Thompson.

All say contamination tends to happen in small pockets. Affected fields are usually near a road intersection (which may require greater rates of application of salt during winter), and feature badly drained soils.

Less than one per cent of the $4.6 million the Ontario Ministry of Transportation has paid out in salt damage claims since 1999 has gone to farms. But it administers only a small fraction of the roads in the province and not everyone who experiences the problem will file a claim.

After ruling out other causes, such as leftover herbicide from corn, and conducting preliminary soil pH tests, the Kortens decided to test for sodium and sampled every 50 feet moving back from Haldimand Road 17, which borders the field. A high sodium count is considered to be in the range of 20-50 ppm, Ray Korten says. A preliminary soil sample tested as high as 406 ppm.

Ray Korten says the contamination costs his family thousands in lost revenue from their pick-your-own and pre-pick operation. To fix the problem, he's been told he will have to install tiles, apply calcium sulphate(in the form of gypsum) and irrigate for at least a year. According to one estimate, tiling the five acres could cost $7,000.

Twenty-year battle

It's been known for years that road salts can have a devastating effect on agricultural production. Ken Slingerland, a provincial tender fruit and grapes specialist, says it is a persistent problem for some farmers whose orchards border well-travelled roads. "Some people have extreme damage almost every year no matter what because they're in key intersections or somewhere along the QEW there's always wind drift."

Peach trees are particularly sensitive. Trees in the five or six rows closest to the road would lose their fruit-bearing capacity because the drift will kill the flowers and the green vegetative buds. Crop production would continue to be affected until about two hundred feet from the road.

Lou Schenck, an owner of Schenck's Farms and Greenhouses near St. Catharines, says his father and uncle suspected salt spray from the QEW was affecting peach tree production on the family's farm as early as the 1950s. But it took until the 1990s and a 20-year court battle to obtain compensation from the Ministry of Transportation. The cash settlement covered six years of losses.

Since then, governments have taken steps to limit the impact of road salts. In 1999, the federal government designated chloride salts as pollutants under the Canadian Environmental Protection Act. Soon after, it formed a multi-stakeholder working group for road salts which developed criteria to identify vulnerable areas and draft a national, voluntary code of practice for salt management.

The code, published in 2004, calls for the development of a salt management plan and the introduction of best management practices for salt storage, snow disposal and salt applications. Today, more than 200 of Ontario's 444 municipalities use it and the Ontario Ministry of Transportation has followed it since 2005.

Henry Swierenga, the Ontario Federation of Agriculture's service representative for Niagara and a member of the national road salts working group, says the voluntary standards mean a better use of employees, equipment and materials used to keep roads clear in winter, but not necessarily a reduction in the use of salt. Each year, Canadian road authorities dump five million tonnes of salt to keep drivers safe. And, with global warming, salt use could actually increase because of the more extreme variations in weather patterns.

Swierenga says that the number of municipalities adopting the code across the country shows that it is working. Environmental groups, however, question whether a voluntary code is enough to control salt usage. 

In 2006, the same year that Ontario's Clean Water Act listed the application and storage of road salt as a known threat to drinking water, the Toronto-based RiverSides Stewardship Alliance and the Sierra Legal Defence Fund raised concerns about salt's effects on surface water. In a published report, the groups called on the province to repeal the Environmental Protection Act's Regulation 339, which exempts road authorities from investigation and from penalties for environmental damage related to salt. The regulation is still in effect.

A growing problem

John Holtrop, who farms corn, soybeans and canola in Keswick, south of Lake Simcoe, links salt-related problems on his farm operation to urban sprawl and related traffic predicts it's "only going to get worse."

He began noticing a build up of road salts in the fields – some of which he has farmed for more than four decades – 10-15 years ago. Some fields are "so bad that the soil turns white." He says test results in the 100-120 affected acres indicate sodium levels at 142 parts per million and higher in spots.

In 2008 Holtrop spread gypsum to counter the salt's effects and has added it to more fields this year.

But he says York Region, responsible for the roads adjacent to the affected fields, should reimburse him for not only the gypsum but also the crop losses. He intends to file a claim once the busy growing season is over.

"If you plant a crop of corn and you've got $600 plus an acre costs and nothing grows because of it . . . it's also an ongoing cost of yield loss and crop loss."

With plans to widen Woodbine Road and extend Highway 404 into his area, Holtrop fears the situation will worsen.

Ross Draper, who farms near Holtrop, also believes government authorities should compensate for salt damage and filed a claim with the York Region last fall after he lost 20 acres of soybeans.

Joe Uyenaka, an agronomist with Cargill Limited, says he has seen salt damage in a number of counties across the province at various times. It is "somewhat" of a growing problem, he says. "The last two years in particular there was a lot of snow and so there's a lot more salt being applied to the road." Road reconstruction can also play a role by affecting drainage.

He notes there are natural areas such as the Keswick Marsh, where sodium levels are higher. To distinguish between naturally occurring sodium and road salts, he takes a reference sample outside of the damaged area. If the sodium is naturally occurring, "you will see it regardless of where you are, whether the plants are doing well or not."

Promising results

The effects of salt on drinking water give rise to more concern than its effects on farming. The ministry has funded a two-year University of Waterloo study that is assessing the impact of road salts management on salt levels in the wells that supply the Regional Municipality of Waterloo's water.

Eric Hodgins, Waterloo's manager of hydrogeology and source water, says that, so far, study results look promising. Samples from the municipality's shallower wells indicate the management plans are producing a net decrease in chloride levels.

Hodgins says that problems with chloride levels in Waterloo's wells surfaced in the mid-1990s and that there's a slower rate of increase in chloride levels in wells situated in Waterloo's rural areas compared to urban areas. He attributes the slower rate to fewer paved roads, since pure salt is not applied to gravel roads. While road salts could also affect private wells, he says the likelihood is small.

The municipality is also realizing that private applications of salt are responsible for a larger share of the problem than previously thought. Hodgins says that Environment Canada estimates these sources contribute seven to 10 per cent of the total road salts applied. "We believe, at least locally here, it could be on the order of 40 per cent." To address this problem Waterloo has launched a program called "Smart About Salt" that accredits contractors and facility operators in safe salt application and storage.

Despite the questions and concerns, Paul Johnson, Wellington County's operations manager and another member of the national road salts working group, says road salting is necessary "because it's the fastest, most effective way of maintaining roads short of plowing." We can't be "killing people to save a tree."

Introducing mandatory controls for municipalities won't achieve any greater reductions in applications. There's already "heavy compliance" among those municipalities meeting the code's eligibility criteria, he explains.

Ray Korten says he understands and supports the idea of public safety coming first but thinks his municipality should help with the costs of tiling and irrigation and that it should compensate him for the loss of production.

Wray Oakes, Haldimand's manager of road operations, says he is aware of the damage salt spray can cause on tender fruit crops, though he's not certain of the effect road salts effect have on the soil. He concedes that there is a possibility the municipality's application of road salts has affected the field and, for this reason, he approved the May reconstruction of the drainage system next to the Korten's field.

The municipality is also developing a salt management plan. "I think without question we are going to identify that area as an environmentally sensitive area in terms of our winter maintenance program."

Haldimand Mayor Marie Trainer, a farmer and a veteran council member, says it's the first time she's heard concerns raised about salt contamination on a field in agricultural production in the municipality.  Trainer, a cow-calf beef operator, says her own property has a huge ditch and fronts two roads, so there's the potential the problem could happen to her, although, to date, it hasn't. As for the question of whether the municipality will provide compensation to the Kortens, "it will be our test case, I guess."

Ray Korten says he'd like to resolve the situation without resorting to lawyers and is beginning negotiations with Haldimand's claims department. "It looks very promising," he says, but he is prepared for the process to be lengthy. In the meantime, he's been busy collecting samples and advises anyone else facing a similar situation to "get yourself super informed" and "test everything."