Double cropping, the practice of planting and harvesting two crops in a single growing season, might seem like the ideal crop strategy on paper. If you can double your crop and double your returns, what could possibly go wrong?
Quite a bit, it turns out, at least when attempted on most Prairie acres.
There are a few reasons for this, but predominate among them is a daylight deficit: there simply isn’t enough to grow two single-season crops to spec.
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As well, the practice requires substantially more water than the Prairies are generally blessed with. This is why its efficacy throughout Canada is limited to southern Alberta’s irrigation belt, and even there it’s largely restricted to crops for silage feed.
Why it Matters: Researchers participating in a new, five-year study are hoping to discover how double cropping can act as a cattle feed multiplier when used in southern Alberta’s irrigation belt.
However, that region’s ubiquity of beef cattle, combined with its irrigation capacity, offers some potential for double cropping. A new, five-year research project led by Mike Gretzinger of Farming Smarter is dedicated to uncovering it.
“Once you add cattle into the mix — or feed into the mix — there’s a whole extra layer of interesting questions and things that we can look at,” says Gretzinger.
The study, sponsored by RDAR and Alberta Beef Producers, is focused on providing the beef cattle industry with the double cropping puzzle pieces that will offer the highest yields and the highest quality feed, says the project’s research paper, which is available on the Farming Smarter website.
Recent improvements in crop genetics and crop options such as hybrid fall rye and short season corn further underscore the need for updated research, it continued.
Know your sustainable cropping practices
With all the sustainable cropping practices talked about these days, it can become difficult to identify one from another, especially when the practices are similar. Gretzinger offers a primer.
Double cropping is essentially planting two crops sequentially in a single growing season and — at least in this context — cutting them for cattle feed. Cover cropping, meanwhile, is specifically intended for fall or spring coverage with the endgame being crop termination.
“Relay cropping would be essentially seeding one crop into another crop that’s already there.… Intercropping just means growing them at the exact same time.”
Hope to improve economic outcomes
The primary objective of the study, which started last fall, focuses on evaluation of the best crop types and harvest timings to maximize yield and quality when using double cropping systems for cattle feed production under irrigation in southern Alberta.
To achieve this, the researchers plan to:
- Determine the best winter cereal crop for double cropping among hybrid fall rye, winter wheat and winter triticale.
- Identify the optimal time of harvest for an initial silage crop.
- Determine which crop type is most effective as a second crop.
- Deliver an economic analysis including the return on investment measurements of double cropping.
According to the project abstract, the knowledge gained through the study will help “enhance agricultural productivity, improve water and nutrient use efficiencies and improve economic outcomes for beef cattle producers in southern Alberta and ensure long-term viability for beef cattle feed production.”
The research plots will be directly seeded into canola stubble using no-till plot drills equipped with commercial seed delivery systems, openers and fertilizer application in a bid to replicate on-farm planting.
Target sowing density will be about 400 plants per sq. metre for hybrid fall rye, winter wheat and winter triticale. Corn and sorghum will be planted with a monosemy vacuum planter on 15-inch rows. Each plot will measure two by six metres.
All seeds will be treated with dual fungicide/insecticide. Nitrogen, phosphorus and potassium will be applied based on soil test results.
Winter crops will be seeded on the same date in early September each year, depending on weather conditions. Second forage crops will be planted as soon as possible (likely two to three days) after the winter crop harvest.
These crops will be planted at two timings to align with the two harvest timings.
The first crops of hybrid fall rye, winter wheat and winter triticale were planted last fall near Lethbridge and Coaldale, Alta.
“And then we’re going to do a cut in late May and another cut in early June, so we’ll take the silage from that,” says Gretzinger.
“The late May (seeding) will allow us to kind of hit a normal seeding window. So we’ll go in and seed oats, barley, corn and sorghum.”
Throughout the growing season, the plots will be measured for stand, vigour, canopy closure, biomass, forage yield, maturity by growth stage, feed quality, soil moisture and crop emergence.
“And then we’ve got a chunk of funding to do the quality analysis, so that’ll be sending it to a lab for getting things like relative feed value, NDF, ADF — all those kinds of things that producers want to know for feeding.”
(NDF stands for neutral detergent fibre while ADF is acid detergent fibre, both of which measure a sample’s fibre content).
Measuring consistency over five years will also play a large role, he notes. Consistency is key because farmers may find success with a practice one year but find it a losing proposition for several years after that.
Green bridging, herbicide carry over two double cropping risks
One thing growers need to be aware of when double cropping, says Gretzinger, is the potential for green bridging and the various complications that creates.
“It’s a would-be vector for wheat streak mosaic if you have a cereal crop and then another cereal crop right after and you don’t have enough time in between.”
Herbicide carryover is one of the biggest negatives associated with double cropping. Considering the nature of the practice and the types of crops considered most suitable for it, this is something farmers need to pay special attention to.
“If you’re spraying products with residual for wild oat control and then you want to grow an oat as your second crop — which is a common choice — you’re obviously not going to be able to do that. There’s lots of things that are going to be specific to exactly what you’re trying,” he says.
Bayer banks on double cropping for fuel
Double cropping is being positioned as a growing tactic for sustainable aviation fuel (SAF) crops such as camelina.
Bayer, for example, recently announced Newgold, a multi-crop seed brand designed specifically for low-carbon intensity biofuel feedstock crops earmarked for renewable diesel and SAFs.
The launch of the brand in Canada includes spring and winter camelina for planting in southwestern Saskatchewan and southeastern Alberta.
“Winter camelina can be double-cropped with soybeans or other summer crops, letting farmers grow two crops in one season,” says Shaun Corneillie, canola, cereals and biofuels business lead with Bayer.
“It may require less inputs than other core crops in rotations and performs well in low-rainfall areas, making southwest Saskatchewan and southeastern Alberta a nice fit agronomically.”
