For the past three decades, potato yields in Eastern Canada have been falling worryingly behind those of other regions. In New Brunswick, average yields have gone up just 1.4 cwt/acre per year since the early 1980s, compared to about 4 cwt/acre in Alberta and Manitoba and at least that high in the U.S. In order to remain competitive in today’s global market, eastern Canadian producers need to offset their rapidly increasing input costs with matching productivity gains. Scientists and industry are stepping forward to try to help.
Part of the yield limitation is obvious: eastern Canadian producers are restricted by limited land, heavy erosion, frequently poor drainage, and a short growing season, and most find irrigation impractical or impossible. But, according to a three year collaborative study by Potatoes New Brunswick, the P.E.I. Potato Board, Agriculture and Agri-Food Canada (AAFC), McCain Foods Canada and the Manitoba Horticulture Productivity Enhancement Centre (MHPEC), two even bigger issues are at play: declining soil health and soil-borne diseases.
In order to try to overcome yield limitations, the researchers tested fumigating the soil for disease, planting nurse crops to protect emerging potato seedlings, reducing soil compaction in potato furrows, growing fall cover crops, and applying various forms of compost in hopes of increasing soil organic matter and water holding capacity. The results were a mixed success, says lead researcher, Dr. Bernie Zebarth, a potato research scientist with AAFC. Adding compost, for example, greatly improved some but not all aspects of soil health, and did not necessarily increase yield in all fields.
From an economic perspective, the expense of major soil rejuvenation like adding compost is a tough sell for growers, he admits. So what can producers do to overcome the yield stagnation?
“What we’re seeing is that there is a lot of diversity out there and you really have to know what’s going on in various parts of your field,” he says. “In terms of practical application, if you can use a yield monitor to get a sense of variability, do some detective work to figure out the issues in low yielding areas – it could be drainage, it could be that you need to add more organic matter, it could be that certain areas of the field have more disease issues – and then target your treatment, that would make costs much more modest. That’s the way we would like to see growers go.”
While industry and scientists are doing their best to help, it will be producers’ knowledge of their fields and problem-solving creativity that will ultimately win yield, he says. “What we’ve seen over the last several years is The absolute biggest advances in yield occur when growers decide this is an issue they need to tackle.that . We can try to come up with answers but it has to be growers posing the questions.”
Expect bolstering yield to require ongoing effort, he adds.
“If you have health problems and your doctor tells you to start exercising, you don’t exercise for a week or a month or a year. You exercise for the rest of your life. We’re just getting started on improving productivity. From now on, it will have to be a continuous process.”