WESTERN PRODUCER — Prairie farmers who dealt with drought during the summer are now facing a soil moisture deficit in several areas as they cross their fingers for snowfall needed to help launch next spring’s growing season.
Although precipitation this fall boosted soil moisture in some areas, “there’s definitely these pockets that have been extremely dry,” said Phillip Harder, a research associate at the University of Saskatchewan’s Centre for Hydrology. “And so, in some ways, things haven’t changed much from those summer conditions.”
One paradox of the current situation is it could make things easier for farmers next spring if the right amount of snow accumulates during the winter, he said.
“If that doesn’t happen, dry remains dry, but if we have a lot of places that already have a dry surface, then you do have good infiltration potential.”
However, this effect can be blocked if there are small buildups of snow that repeatedly melt and freeze on the surface layer of the soil, he said.
“That will reduce our infiltration potential moving forward, so the more of these false starts to winter that you might have all reduce infiltration potential incrementally.”
Although it is difficult to make seasonal forecasts for the winter, Harder said “the big indicator that most people will look towards is, ‘are you in an El Nino or La Nina?’ The last three years, we had three straight years of La Nina winter, which led to fairly high snowfall accumulation on average.
“But right now, we’re looking at a strong El Nino the last time I checked, and so that is typically associated with warmer and drier. There is a significant variability within that, and on the Prairies, you only need one or two storms to change your situation from no snow to a way more than you know what to with scenario, so it’s really hard to have that dialed in.”
However, the indications are that snowfall will generally be lower this winter than it was in the previous three years, he said.
“There’s always going to be an area of drought and an area of flood somewhere… but areas that are dry at the moment, they are at a higher vulnerability to the continuation of that situation.”
In much of southern Alberta south of the Trans-Canada Highway precipitation has declined by as much as 600 millimetres during the last five years, said Ralph Wright, manager of the Ministry of Agriculture and Irrigation’s Alberta Climate Information Service.
“That means they’ve missed out on an entire year and a half of moisture in the last five years.”
However, soil moisture has rebounded in much of the region, he said.
“If you were to draw a line from Calgary to Medicine Hat, everywhere south of that is near normal.”
During a Nov. 1 interview, Wright credited precipitation during the previous four or five weeks.
“Now, that 小蓝视频 said, normally it’s quite dry down there, so it really doesn’t mean there’s necessarily an oversupply of moisture,” he said.
“It’s just recovered from the exceptionally dry conditions we’ve had this growing season, but at least it’s a good start for next year. Between now and then, anything can happen, right? It’s very difficult to predict.”
Wright said the Special Areas in east-central Alberta near Saskatchewan contain pockets of one-in-50-year lows in terms of soil moisture for this time of year. Lows of at least one-in-six-to-12 years extend north from the Trans-Canada Highway to Wetaskiwin, with pockets of one-in-50-year lows in the Lloydminster area, he said.
“And generally, most areas are sitting at about one-in-six-year lows for this time of year, and then through the Peace country, we’ve got some pretty dry conditions in the central areas and also north as well.”
Although it is getting to the point in the year where not much can be done in terms of farming practices, there is a longer-term conversation that producers must have about water conservation, said Harder. It includes managing crop residue in stubble through practices such as zero tillage to maximize the capacity to catch and trap snow as well as reduce sublimation losses, he said.
“In areas that are water-stressed, that can be a fairly reliable way of increasing water on your landscape. You can’t really change precipitation, but you can store snow much more effectively by increasing stubble heights as much as you can.”
Harrowing can also affect soil moisture, said Harder.
“Yes, it’s nice to have fields prepared nicely for the coming year, but there are implications to the ability for soils to retain water if they have some pretty heavy harrowing going on.”
Producers in southern Alberta are sticking to their crop rotations, said Ken Coles, executive director of Farming Smarter near Lethbridge.
“Certainly, with a drought year, there’s going to be a little bit of special consideration as to what you’re going to establish, but I mean winter wheat is always an interesting option,” he said.
“And we did actually get pretty good winter wheat established this fall. There was some fall moisture that was able to get things germinated, but I’m of the opinion that the fall-seeded crops are going to make most efficient use of the moisture that we tend to get in the fall and the early spring.”
Farming Smarter is involved in research to help producers in southern Alberta conserve soil because of drier winters and increasing wind erosion. It can be so severe on irrigated land that soil has filled ditches and buried fence lines.
It can be tough for farmers to establish fall cover crops if they don’t have enough moisture, said Coles.
“And in many cases (this year), we were in irrigation rationing so we were out of water, and the St. Mary River Irrigation District actually shut down early, so the opportunity to irrigate those later-seeded cover crops just wasn’t there.”
Reservoirs have also been empty, increasing uncertainty about whether full rations of water will be available next year, said Coles.
“I think this year in particular, folks are definitely going to be thinking about how are we going to set things up?” he said.
“And where are we going to allocate water to our higher value crops, and which crops can do the best with less? That’s just unfortunately the situation that we’re in right now, but it is a little bit different than I think what irrigated farmers are accustomed to.”
Drought tends to occur in 10-year cycles followed by 10 years of wetter weather, said Coles. Although he estimated southern Alberta has faced drought for about seven years, the adoption of practices such as zero tillage and better crop rotations have helped farmers cope with the situation.
“There’s a lot of people that are surprised with how well crops are doing despite the reduction in water, so that’s a good testament to the work that’s been done in the past, and there’s probably still more work to be done, especially under irrigation. In that sense, it’s how do we do a better job conserving the moisture that we do have and in the crops that don’t require near as much water?”
Many dryland farmers are facing low reserves of soil moisture, which means the first step is to take soil cores, said Coles. Producers are good at evaluating if there aren’t enough reserves for big crops and cutting back on things such as fertilizers, he said.
However, it is hard to predict what next year will bring, he said.
“We could get a bushwhack load of spring moisture, and then that’s going to affect what the nutrient plans are for the year, too, so it’s kind of a guessing game.”
Harder said climate change is expected to complicate things for prairie farmers by boosting weather extremes. Although temperatures are becoming warmer, climate models also suggest that to a less certain extent, there will also be an increase in precipitation, he said.
The challenge is rising temperatures will also boost evaporation, potentially resulting in less water for crops, he said. “And so, the general concern is that even if we see an increase in precipitation, it may not translate into an increase in yield because it’s all very nonlinear in terms of evaporative demand.”
It is tough to figure out what is occurring because the climate in the Prairies has traditionally been noted for its extremes, said Harder.
“It has been and it continues to be difficult to differentiate the extreme climate, and the things we see year to year, from what’s happening in terms of surveying subtle, long-term shifts.”
