Livestock producers have been scrambling for their neighbours’ straw, but growers may have been reluctant to let it leave the field.
Attractive straw prices went head to head with the desire to chop and spread as growers weighed the balance between a secondary income and the cost of exporting those nutrients rather than working them into the soil.
As of Sept. 10, Manitoba Agriculture’s hay listing was advertising round-baled straw for $15 to $20 per bale.
For some growers though, the promise of a secondary crop could not outweigh the perceived nutritive value of leaving that straw in the field.
Michael Harms of Mather says he was not among those baling extra straw this year. His mixed grain and livestock operation does harvest straw, he said, but only enough for his own use.
“I’m zero till in my cropping,” he said. “I like to keep a little bit of cover on top to help keep moisture in the spring, especially if we’re going to be dry.”
He has not been approached about selling his straw, he said.
Another user, Andrew Dalgarno of Newdale, argued that he would get more benefit by spreading than the $5 per bale he was offered for the straw. It might be cheaper to bale, he later admitted, given the horsepower and gas needed to chop and spread, but maintained that the practice would be better for organic matter.
Other producers have been warmer to the idea. Taking the discussion to Twitter, Brooks White of Lyleton, Man., suggested that he would “prefer to leave all straw in the field,” but would be willing to bale if producers were worried about feed shortages.
“We are very lucky to have great neighbours who dropped a pile of acres of wheat and canola straw for a couple of us to make sure we had enough feed for the winter,” another producer, Clayton Robins of Rivers, said. “We are baling up their kochia patches to feed too, so helping them as well.”
What do the experts say?
Agronomists and extension staff commonly warn producers to consider the nutrient cost before deciding to bale.
In a 2015 article in the Western Producer, agrologist Thom Weir said straw removal can speed up soil nutrient loss and contribute to short-term soil impact. In low-phosphorus soils, removing that crop residue might steal some of that nutrient needed to jump-start growth in spring, although it might actually be a short-term boon in terms of nitrogen, since worked-in straw might immobilize the nutrient.
One of Manitoba’s staunchest soil health advocates, however, says baling straw this year probably made little difference to a producer’s field.
“If you’re thinking about the carbon and the soil health and such, the amount of carbon that goes into the system from, say, a high-residue crop year, is not a huge amount in terms of how quickly you’re building something like organic matter,” Marla Riekman, land use specialist with Manitoba Agriculture, said.
Guy Lafond, an AAFC researcher out of Indian Head, Sask., has also examined the question.
His study, which looked at data from the station’s long-term crop rotations over 50 years, found little overall carbon impact from baling.
“A lot of that carbon is gassed off or lost during that decomposition process, so that’s why they weren’t finding it was a huge deal to take some of that organic matter or straw residue away,” Riekman said.
Lafond’s work has also suggested that, depending on harvest system, baling only removed 26 to 40 per cent of “total above-ground crop residues other than grain.”
Farmers should have expected to lose some nitrogen by baling this year, Riekman said, although the removal from one year would require little shift in nutrition plans for the year to come.
“The majority of the nutrients that we’re actually taking out of the soil are actually going off in the grain,” she said. “It’s not a whole lot that’s left in the straw and so, if the majority of it is going off in grain, you’ve already removed it to begin with. That straw then, yeah, sure, it puts some nutrients back in, but it might not be a high amount in terms of how much fertilizer you’d have to put down next year to replace (it).
“The balancing act is really, what’s the need? In a year like this year, when we need to feed straw because we’re going into a feed shortage, it’s OK to remove that straw and not worry too much on what the loss is on that field, because the need for straw as a feed source will be so much greater.”
It is still unclear how much producers will be relying on straw for feed this winter.
Manitoba Agriculture puts nutrient value of wheat straw at 24 pounds of nitrogen per acre, three pounds of phosphorus and 911 pounds of carbon. Nitrogen and phosphorus content is less for oat straw (11 and 1.7 pounds an acre, respectively), while carbon sits just above wheat (918 pounds an acre). The numbers are drawn from provincial crop nutrition expert John Heard and his work to measure nutrient loss from burning crop residue.
Baling straw will remove less than burning, Riekman admitted, although Heard’s work should largely hold true for baling since the study measured loss from burning only windrows, not all stubble in a field.
Both Dalgarno and Harms also argue that the logistics of selling straw sours the temptation to bale.
Both say they have had customers back out at the last minute, leaving them with unwanted bales or windrows.
“I’ve done that, did all the work, and then I was able to sell some of it, but a large majority of it I had to keep and it took us many years on our mixed operation to use it up,” Harms said.
In a worst-case scenario, he argued, the abandoned straw may hinder the ability to do fall field work or lead to compaction issues if the ground is wet during baling or pickup.
Tim Clarke, provincial livestock specialist in the Interlake, says he has anecdotes of producers dropping straw this year, although brittle, desiccated crops and the popularity of rotary combines has limited how much straw can be physically baled.
“From the grain farmers’ perspective, the value of the soil nutrients from the soil are usually higher than what the cattle producer is prepared to pay them for (those nutrients), so that’s an issue,” Clarke said. “And then there’s other challenges associated with baling up straw that are becoming more relevant all the time and impact how much straw that gets baled up.”