Manuresheds would re-connect livestock production to crop farming by identifying where resource could be distributed
Most rural Canadians understand the concept of a watershed, but it’s unlikely that they’ve ever heard of a manureshed.
About 50 years ago, mixed farms were common in Western Canada. Now, intensive livestock production, such as hog barns, is a separate industry from growing crops. Scientists with the U.S. Department of Agriculture and Agriculture Canada want to re-establish the link between livestock and crop production.
“The transition (to specialized production) has created efficient, high-yielding crop and livestock operations,” the USDA said in a June release.
“But it has also severed a longstanding symbiotic relationship where the excess nutrients created by the manure had productive uses.”
USDA researchers are touting the manureshed concept to re-connect livestock production to crop farming.
The idea is that parts of rural North America have a high density of livestock farms. A manureshed is a geography where manure from such farms could be distributed. One example is southeastern Manitoba. It’s known as “hog alley” and is the heart of the province’s pork industry. However, the region doesn’t have enough cropland to use all the manure or an economical way to transport the hog manure to land where it’s needed.
The manureshed is a way of thinking differently about this problem — to make agriculture and nutrient management more connected and sustainable.
“Separation and concentration (of livestock and crop production) has occurred. What can we do to close these cycles?” said Sheri Spiegal, a USDA rangeland ecologist in Las Cruces, New Mexico.
Spiegal is the lead author of a paper on manuresheds published in Agricultural Systems this June. The paper has about 20 authors, including Shabtai Bittman, an Agriculture Canada researcher in Agassiz, B.C.
“Manuresheds can be managed at multiple scales … on farms with both animals and crops, among animal farms and crop farms within a county, or even among animal farms and crop farms in distant counties,” the paper says.
Raising livestock and using the manure to fertilize crops is not a new concept. It’s been around for thousands of years.
The difference now is that many farmers have no connection to manure.
They use commercial fertilizer for their crops because it’s effective and convenient. Manure could be part of soil fertility on more farms, but it’s not a priority for producers or society.
Part of the challenge is getting the public and politicians to pay attention so they that care about recycling nutrients in agriculture.
“Not a lot of folks … are aware that phosphorus, rock phosphorus, is a finite resource,” Spiegal said.
“I think a lot of consumers would find that interesting, just like they care about the need for renewable energy.”
A large part of the challenge is technology. Scientists need to discover new ways of storing and de-watering manure and recovering nutrients to make distribution more feasible.
For now, a manureshed is mostly a big picture concept — to get the conversation started.
But in Manitoba, some policy makers have been thinking about this for a while. They just didn’t use the word “manureshed.”
Several years ago, the Manitoba Livestock Manure Management Initiative (MLMMI) commissioned a study on transporting manure by pipeline from southeastern Manitoba to areas that need phosphorus. The report found that a 55 kilometre pipeline would cost $42 million for just construction.
“In addition to the cost, you could expect significant public opposition to something like this,” said Doug Small of DGH Engineering, the firm that studied the pipeline.
“It would have to cross watercourses, for example. The public would be concerned about perceived risks.”
MLMMI has looked at a number of other options, such as systems that separate the phosphorus and nitrogen in the manure. Those systems are also pricey.
“Because we have to operate in very cold temperatures, it gets to be a very expensive installation, and the operating costs turn out to be very high as well,” said PAMI vice-president Harvey Chorney.
The biggest challenge in Western Canada may be distance.
The USDA scientists identified several regions in America where distributing manure could make sense, such as the Carolinas, which have hundreds of hog and poultry farms.
However, the distance from a large hog barn to a farm that needs phosphorus in South Carolina may only be 70 km.
Transporting a manure byproduct 350 km from hog barns in Killarney, Man., to farmland in Weyburn, Sask., is not economical right now, although it might be with financial incentives and the right technology.
“It (a manureshed) is a guide or framework to get people to think … about the wicked problem of nutrient cycling and modern agriculture,” Spiegal said.
“(There’s a) need for recycling nutrients for our sustainable future.”