What's that Smell? Manure.

Tuesday, September 26, 2023

And with high fertilizer prices, this stinky stuff might keep more dollars in your pocket.

By Stacy Berry

As a farmer, you've likely looked at rising fertilizer prices and thought "this stinks." You know what else stinks, but may be an economical option for your farm? Manure.

"Manure is better than fertilizer in a lot of ways," explains Kelsey Klyzub, sales leader with Cargill, from Vermilion, Alta. "It's high in phosphates, lots of potassium, sulfur, nitrogen. It's a complete package in a lot of ways."

Rianne Bouma, an agronomist with Nutrien Ag Solutions in Stony Plain, Alta., agrees. "People don't often think about them, but there are lots of micronutrients present in the manure itself. And the buildup of organic matter with regular manure application can be invaluable."

Melanie Baldwin currently lives in South Africa but practised agrology in both Alberta and British Columbia. "Livestock manure plays an important role in nutrient cycling and increasing biodiversity. The complete nutrient composition is dependent on species and diet."

The Ontario Ministry of Agriculture, Food, and Rural Affairs offers producers an online factsheet with a breakdown of what nutrients different manures contain and their expected availability, which can be a great start in your nutrient management plan. However, agronomists recommend that farmers get their manure sampled so they know what theirs contains. Most of the same labs to which a farmer might send a soil sample can test for manure composition as well.

Increasing organic matter in your soil provides a plethora of benefits, says Klyzub. "When you add organic matter, you increase water retention, buffering capacity, soil stability."

Baldwin adds: "Livestock manure contains large amounts of microorganisms and invertebrates, which aid in nutrient cycling and ensure the nutrients are in a bioavailable form, readily taken up by plants."

Of course, Baldwin, Bouma, and Klyzub all warn producers that they can have too much of a good thing.

"If you apply manure at a rate to achieve your nitrogen requirements, you might be overdoing the phosphorus, and sometimes even the potassium, which can cause micronutrient deficiencies," explains Klyzub.

Baldwin: "When there are excess nutrients, they leach into water systems and cause negative consequences for aquatic and other life."

Further, Bouma adds that "manure tends to be high in phosphorus, so applications over years can lead to a build up of phosphorus. This can lead to eutrophication."

Eutrophication happens when a water body is excessively rich in nutrients. This leads to dense plant growth, which takes away too much oxygen from the water and can result in the death of plants and animals.

Bouma stresses that "the more we look at sustainable ag and climate programs and emissions reduction goals, we need to be having more conversations about what we're doing with manure and how we're managing it. That is why 4R practices are absolutely crucial when dealing with fertilizer amendments, including manure application."

The 4Rs: right rate, right time, right place, and right source.

"Take into consideration what kind of manure you're using. Get it sampled so you know what's in it, and plan the rest of your nutrient management."

The time of application matters, too, and Bouma recommends fall applications. "Spring application or applying on frozen ground increases your runoff/volatilization loss compared to late fall and working it in. The government has guidelines for manure application for a reason."

Various provincial governments have manure management aids to help in planning applications, easily found online.

Bouma has some more practical reasons why she prefers fall application as well. "Equipment is heavy. Work when the soil is drier in the fall, so you reduce compaction. Plus, when you fall-apply, you're ready for spring, instead of adding one more item to the list."

Kevin Porter, a farmer in Stony Plain, Alta., says he doesn't really like handling manure. "I mean, I like it because it has lots of nutrient value, but it's extremely difficult to gauge the value of nutrients per acre, and it takes time for the nutrients to show up in the soil samples."

Porter is neighbours with a chicken farmer, so this type of manure was convenient and close to his fields.

One of the benefits that Porter sees with manure application is that "what you put in, you get out – within reason and balance, of course."

The surprising downside of manure application for Porter was lodging. "Standability and even maturity across the field is quite different with manure as compared to the prescribed, specific amounts of chemical fertilizers."

Despite the frustrations that come with manure application, it is "absolutely worth it" for Porter to apply manure. "Manure provides fibre and biodiversity. I think it's the No. 1 way to improve your soil."

Porter continues: "We've gone from full-rate fertilizer to half-rate. You do reach a point of diminishing returns, though, where (manure application) stops being worth it."

Bouma and Klyzub agree that applying manure is financially sound. However, "it's difficult to provide a dollar value to manure, unless you get it tested so you know your nutrient ratios," explains Bouma.

"As well, there are other costs and benefits of manure beyond nutrients. The benefits of not storing waste in your yard, for instance."

Baldwin knows from experience that it's important to manage your manure. Too much sitting around and "you'll see increased fly and parasite populations."

However, when manure is applied reasonably, a farmer can expect a "reduced pest load and increased resilience of the ecosystem."

Garfield Buck, a farmer in Peers, Alta., once raised hogs, and applied "all liquid manure, usually once a year." He produced enough to cover his closest quarters of land regularly. "To this day, the phos numbers are still high."

Buck misses his regular supply of manure. "It was definitely worth it for me – nearly zero transport costs. Considering the price of fertilizer now … and it was really nice to use a natural fertilizer. It really put fibre back into the soil."

Liquid manure is different from solid manure in several ways, Buck says.

"I had an open lagoon, so depending on rainfall, nutrient concentrations could change drastically. The liquid manure was 'blown' on with a vac truck. And liquid manure needs agitation because the solids go to the bottom."

No longer raising hogs, Buck does have some sheep, and he treats the solid manure differently.

"Manure from the sheep has been piled up regularly and allowed to sit for several years. Do you lose some nutrients with the breakdown? Probably. But allowing it to break down gives you a better spread of the solid manures."

Baldwin agrees. "Composting manure can be time-consuming, but ensures the nutrients are more available for the plants."

Although Buck produces far less manure now, he has begun applying the sheep manure to his pastures. "It's amazing the difference on the pastures where manure has been applied, and how fast it greens up."

Klyzub doesn't have any customers who have recently taken up manure application; "most producers who apply manure primarily raised livestock and grew crops to feed them." That's a key limitation of manure. "Although it's not typically as expensive as fertilizer, it is hard to come by in meaningful amounts. However, I do encourage farmers to look for a manure source. Places that produce a lot of it often want a place for it to go."

On the Prairies, cow manure is the easiest to find. However, is it the best type of manure?

Actually, no.

Klyzub's favourite manure is poultry. "It is the stinkiest," she concedes, "but it has the nicest nutrient ratios."

Porter is happy to have his poultry manure. Fortunately, "it's layer and pullet manure, so it doesn't have as high of nitrogen as broiler or hogs," so it's a little more manageable for his applications. He could do without the smell, however.

Bouma's dad once worked on a crew spreading manure with a vac truck. "We always knew which type of farm he had been on. Cows were okay, pigs were smelly, but chickens – stay away from me."

Another potential downside of manure application is weed management. "Not every animal degrades weed seeds to the same degree," explains Bouma.

Porter had the same problem, although he did learn the harder way.

"Because you're adding lots of nutrients, weed control often needs to be ramped up. When you grow feed and are blending cereals, make sure they are herbicide compatible."

Despite some of the downsides, Porter tells farmers to "never turn it down. Manure is probably the best way to extract nutrients. The toughest part is knowing what you're putting on, but that's where my agronomist comes in."

Bouma agrees. "Start with a baseline soil test, talk to an agronomist, and don't overdo your first year of application. You can put manure on too thick, where it can hold too much water and rot the plants. Put on a reasonable amount, incorporate where you can, and go from there."

Klyzub encourages people to be open to using it. "I would reach out to another farmer in the area who has a manure stock, and ask them about a deal. It's so beneficial – it can provide you with such good soil health benefits."

Buck is looking forward to spreading more sheep manure. "Manure is a fantastic product and you can't duplicate it. If we could have more manure, we would."

So if you are looking for a way to augment your nutrient management plan and have a neighbour with a manure supply, it is definitely worth starting the conversation.

If you do strike up that conversation, though, ensure you have a few minutes to sit and chat. As Baldwin says, "I never knew I would have this much to say about manure." BF