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Manitoba potato producers sing the praises of fertigation

The Wiebe family has been growing potatoes near McGregor, Man. in the southern area of Manitoba since 1966.

The Wiebe family has been growing potatoes near McGregor, Man. in the southern area of Manitoba since 1966. The family produces Ranger Russet, Russet Burbank and Innovator varieties, largely for the Carnation Foods plant in Portage La Prairie, Man. Seven years ago, the family decided to relocate their operation. The new growing location had coarser soil.

“We found that we were running out of nitrogen late in the season,” explains Sheldon Wiebe. “That was affecting our yield and quality due to leaching. We had to do some late season rescue work.”

In 2010, the Wiebe family was approached by David Rose and Wade Gerner with Simplot to see if the Manitoba growers would be interested in implementing a fertigation program – the application of fertilizers, soil amendments, or other water soluble products through an irrigation system – that Gerner, a potato grower from North Dakota, had been using with much success on his operation.

A year later, Sheldon Wiebe had the opportunity to share his fertigation experiences as part of a panel discussion on the pros and cons of using fertigation to enhance potato production. Other panel participants included Wade Gerner and Brent Metcalfe of WM Ventures near Treherne, Man.

Metcalfe and his partner, Barry Watson, began growing potatoes – mostly Russets with some Umatilla – in 2003.

“We began experimenting with fertigation in about 2006,” says Metcalfe. “We used to do broadcast nitrogen. We would get some nitrogen from the planter fertilizer and then top dress at hilling.”

He and Watson became serious about fertigation in 2008 and have adopted an “aggressive planned fertigation program. It makes agronomic sense to me to match nitrogen application to when the plant actually needs it,” says Metcalfe. “Fertigation increases nitrogen efficiency. The results are smaller, more compact plants which are less susceptible to late blight and other diseases.”

He adds that fertigation spreads out the fertility bill throughout the season. The process also provides the option of pushing the crop in a long growing season or saving expenses in a short growing season.

Wiebe says he begins to fertigate when the tubers are a dime to nickel in size with about 10 to 14 tubers per plant.

“We start with an application of 30 pounds per acre and add another 15 to 30 pounds weekly – depending on the recommendations from Wade or Doug – until the end of July or the first week of August and considering plant heath and crop stage,” he says.

Among the factors to consider are plant health through visual appearance, petiole checks and soil tests, says Wiebe.

“We used some of the tools that Doug, Wade and Andrew Ronald (at McCain Foods) suggested,” he says. “I also listened to my employees that were looking after the irrigation and were in the fields every day. We have a great team of employees who do a great job.”

Metcalfe says he and Watson try to have all passes done by the first week of August. “We look to try to have petioles at about 7,500 ppm to 10,000 ppm and soils at about 60 pounds of nitrogen at August 1,” he notes. “We want petioles and soils trending downward as the season moves forward. An upward trend toward the end of the season can lead to delayed maturity and decreased gravities.”

Metcalfe adds that for fertigation, growers will need a high capacity pump and tank at each pivot so the pivots can be spun quickly and timely application can be achieved.

The Wiebe farm purchased three 50-gallon-per-hour pumps to add to its existing 30-gallon-per-hour pump to help fertigate with six pivots.

“We place a 1,200-gallon tank at each pivot centre,” explains Wiebe. “Timing isn’t too hard to achieve as long as you stay ahead with irrigation.”

Wiebe says that early in the 2010 season, because of the excess moisture, his team ran their pivots as fast as they could to put the nitrogen on.

“Moisture can also be an issue for servicing the fertilizer tanks,” he says. “We needed a front wheel drive cart that had a lot of flotation.

“It is also important to have a good nozzle package and the right nozzles for fertigation and irrigation.”
Overall, Wiebe is very happy with the results he achieved after using fertigation.

“We saw some amazing yields … from those fields we fertigated,” he says. “Our size profile was very nice and solids were right in the sweet spot. We usually have trouble in the sand to keep solids from going too high.”

In 2011, Wiebe and his crew fertigated every field “because of the great efficiency and results we saw from [the 2010] season.”

Metcalfe says that while fertigation is beneficial, “it is not an exact science. Determining application by appearance of crop is somewhat of an art.

“You have to ensure enough nitrogen up front to get the crop started and growing until the tubers are round. You have to be done with applications by the first week of August. And you shouldn’t go from applying 10 pounds to 30 pounds abruptly at the end of the fertigation season.”

For 2011, Metcalfe increased the total amounts of nitrogen applied through the pivot to 80 pounds on Russets as compared to 65 pounds on Russets (and 85 pounds on Umatilla) in 2010.

He also considered used fertigation to apply phosphorus and sulphur.