Water management — drainage is expensive, but so is flooding

Panellists at last winter’s Potato Production Days discussed
options for handling the excess rain of recent years

Any farmer will tell you that flooding is a major hassle and cost to any farm when it happens — but just how big that bill can be has always been a bit of a guess.

A recent report by BMO Economics (Bank of Montreal) put a figure on it though, says Dr. Ranjan Sri Ranjan, a professor of agricultural engineering at the University of Manitoba.

“BMO estimates that heavy rainfall and flooding costs Prairie farmers $3 billion — if we spent just a fraction of that amount on proper drainage and water management, we could make great improvements,” Sri Ranjan told growers at this winter’s Manitoba Potato Production Days.

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Ranjan, who was moderating a discussion on drainage approaches, also stressed that the improvements would stretch well beyond just getting water off fields. It could also make overall potato quality better and more uniform.

“Some of the main problems of the potato industry are storage rot and sugar ends,” he said. “I think we can look to better water management to improve this situation.”

Better water management, sure — but where to start? There are different approaches, price points and philosophies and none is entirely right or wrong. Two potato producers told growers about their experiences.

Stan Wiebe of Beaver Creek Farms farms on predominantly Almasippi soils near MacGregor. They have six to 12 inches of topsoil, two to four feet of yellow sand, then a clay base. This combination makes drainage a challenge, especially during heavy rainfalls.

“When the sand becomes saturated, there’s nowhere for the water to go,” he said. “One- and two-inch rains are appreciated, but a few times a season you suddenly get a very big rain, which is a problem. When you come to the rain gauge at the end of the field, and it’s already three, four or five inches, you know there’s going to be damage.”

By the mid-1980s, following a number of losses over the years to high moisture, Wiebe began to experiment with ways to reduce this moisture problem. After doing some research, he purchased a dammer/diker which rips up the soil to facilitate drainage and pokes well-like holes in the topsoil to trap moisture and prevent it from running to low spots.

“It did a good job — by that I mean it did exactly what it was supposed to do — but it didn’t solve the problem, because of that clay level farther down,” Wiebe said. “Now it wasn’t just the low spots drowning out, it was also the high spots.”

Tile drainage

The next step was a bit of research on tile drainage, including some consultation with Ken McCutcheon, an Ontarian who worked on some of the earliest tile drainage projects in Manitoba. He analyzed the local soils and explained how the system worked, Wiebe said.

“It was overwhelming,” Wiebe said. “We couldn’t quite understand it, and we knew it would cost a lot. We decided to wait and see how it worked out for others who were trying it. But after a few years, we realized the only way to know it truly was by trying it out.”

In 1998 Beaver Creek added its first tile drainage to a 270-acre field, using equipment imported from Ontario, adding about $100 an acre in shipping costs alone.

“We hadn’t grown potatoes there for 15 years, and we thought if it worked there, it would work anywhere on our farm,” Wiebe said.

It worked so well, they kept tiling every season, adding between 200 and 500 acres to the total every fall, a project Wiebe admits was quite daunting.

“You’d be working after harvest, and the weather would be quite terrible, on something you don’t see the results of right away — so you really had to believe in it,” he said. “Now it’s very much a turnkey operation — the contractor will apply for the licence, put in the tile itself and even smooth the field back out.”

The rains kept coming, as expected, and flooded fields continued to be a common sight in the area, said Wiebe. But he found that he wasn’t going out much searching for damage anymore, but rather making a round of his fields to watch the drainage system in action.

“Now there’s healthy and clean filtered water running out the tile outlet, and it’s a beautiful sight,” he said.

Probably the single greatest test was the 2005 growing season, which featured a wet spring and extreme rain events at the end of June and early July.

“That season, we saw both the benefits and the limitations, because the water was so excessive,” Wiebe said.

Their untiled canola averaged 18 bushels an acre, and the tiled was at 52. One half section of untiled canola yielded just eight bushels an acre, while a nearby tiled half suffered a bit of damage between the drain runs, but came in at 53 bushels.

That won’t happen every season, but Wiebe stresses that historical weather data suggests it will happen enough to make the system worthwhile. A two- to five-inch rain event, for example, happens once every three years in Wiebe’s area, according to Environment Canada data over the past 30 years.

“Tile drainage is not a game changer every year, but it can be a huge game changer those years,” Wiebe said.

Does it pay?

But does it pay in the end over the long haul? That depends on the crops and soils on individual farms, Wiebe said. Over time they’ve seen a 15 to 20 per cent yield increase on average, but he also said it can range from zero to 400 per cent. On their farm it’s worked out, and he ran a quick breakdown of the costs and income impact for the audience.

“On our farm, it takes about 10 years to pay at 50-foot spacing, financed at seven per cent, based on this crop rotation — potatoes, corn, canola and cereals,” Wiebe said.

Wayne Derksen of Winkler’s Hespeler Farms told the audience he made the decision to make the operation’s first foray into drainage out of sheer frustration during the annual budgeting process. He’d already trimmed all the fat he possibly could from expenses and couldn’t do anything about the price of potatoes when a senior member of the operation asked him to look at the numbers again.

“He said, ‘Run them again, there’s no way we’re working that hard for that little money,’” Derksen recalled with a chuckle.

Derksen knew that if he could tame the moisture challenges the farm faced, he could boost yield and improve quality and consistency of their product and capture a few more dollars.

“I was tired of seeing low spots drown out,” he said. “The ridges were always dry, the low spots too wet.”

Trapping the rain

But he also knew he’d have to find a cost-effective route to this goal and to find one he turned to Wiebe’s first solution — reservoir tillage to trap the rain where it fell.

“It was a rather inexpensive capital cost — we made our own equipment and it took less than $14,000 to build it,” he said. He also said the results they found from it were even better than they’d hoped.

“We budgeted a five per cent yield increase, and wound up with as high as a 15 per cent increase,” he said. “We basically had the totally opposite experience that Stan did, and I think it goes to show the differences in areas.”

For their farm, the lower-cost options have proven suitable, he says, and the baseline for determining success or failure is profitability.

“For me it’s all about where the rubber hits the road, how it affects the bottom line,” Derksen said. “The best bang for buck is not in tile drainage — it’s in land levelling and ditching. This is where to spend your first dollar and it’s going to give you the best return.”

Derksen also stressed that drainage can come with its own associated issues, especially when infiltration doesn’t keep up with rainfall, leading to water flowing on the surface. In that case both neighbours and regulations have to be taken into consideration, he said.

“We’ve been very fortunate with the people we’ve been working with,” Derksen said. “We’ve found we can implement drainage plans with them.”

More recently the operation has also experimented a bit with other water management strategies, including tile drainage on some acres. He said his gut feeling is that the system could be refined for individual fields and the soil conditions there, for example, by changing the common 50-foot row spacings.

“I feel we could widen that in some places and narrow it in others,” Derksen said.

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Gord Gilmour

Gord Gilmour is Editor of the Manitoba Co-operator.

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