By Melisa Luymes
Agricultural technology is always changing, and manure technology is no different. Building on a three-part video series on Manure Innovation, a “Manure Tour” went across Ontario and talked with 250 farmers about manure management and innovation. The tour ran in early February in Moorefield, Dashwood and Kemptville in a highly interactive discussion-based format. In total, 16 people spoke on the four panels and the groups toured six farms.
The events were funded by the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), coordinated by Farm & Food Care Ontario and delivered by a relatively new farm organization that works with a lot of manure – the Ontario Professional Agri-Contractors Association (OPACA).
Manure management is critical for successful farming in Ontario. Last year, the federal government set a target to reduce nitrogen emissions by 30 per cent and followed up with its On-Farm Climate Action Fund (OFCAF) that set nitrogen management as one of its priorities, along with cover crops and rotational grazing.
Farmers know that manure application is important for improving soil health, resilience to both rain and drought stress, having great yields and saving on commercial fertilizer. It is an asset to the farm, but it can easily become a liability if nutrients are lost to the air or to water. Manure creates methane, ammonia, hydrogen sulfide, nitrous oxide, and other gases as it sits in storage or is land applied. While some of these are greenhouses gases, all these gases translate into lost nutrients for a farmer at the end of the day. Similarly, nutrients can be lost to waterways depending on the rate, timing, and placement of manure application.
Manure is biological and complex, so there isn’t a silver bullet to management. It means taking a step back to see the big picture and all the incremental improvements that can be added to a manure system.
Manure considerations begin with feed and bedding. Hog farmers on the Manure Tour noted that phytase in their feed has had a tremendous impact reducing the phosphorus content of the manure. The dairy farmers discussed how bedding impacted manure. In Eastern Ontario, straw bedding is popular but it creates a thick crust over the pit and takes a lot of work to agitate and apply. Sand bedding is more popular in Western Ontario but has created a whole new level of management. Sand has no nutrient value but drops to the bottom of the pit and takes manure solids with it. Sand decreases storage capacity and there is an added cost for digging the pit out with a high hoe and spreading the (nutrient dense) sand solids. Sand pits can be agitated but contractors can have trouble agitating pits to get nutrient consistency, and their equipment takes a beating, which is why they charge farmers extra for sand.
On the Manure Tour, participants visited Stonecreek Farms outside of Woodham, and were able to see their bedding recovery system. Milking about 700 cows at that location, their 440’ x 265’ cross-vent flush barn was built in 2018 and includes a back room for their BeddingMaster composter. The manure is run through a press to remove the solids, which are composted in a large drum and spread back to the stalls to maintain four inches of bedding, continually re-used. The remaining liquid portion of the manure is much easier to handle as they have installed pipes underground to pump their manure to their fields.
In Europe, regulations have driven barn innovation to new levels to manage manure gases. When the urea in urine hits the urease enzyme in solid manure, it begins to create ammonia and nitrogen loss. That’s why both Lely and Hanskamp have designed ways to keep #1 and #2 separate from the outset. Lely’s Sphere unit has urine drop below the barn though small slats, while its signature red robots scoop up poop and vacuums collect any ammonia from the barn or storage to turn into liquid nitrogen. In a different design, Hanskamp has created the Cow Toilet, a robotic “urinal” which comes behind a cow in a feeding stall and keeps the urine stored separately. It has also made a Bedding Cleaner barn system that acts like a kitty litter at-scale, clumping and removing manure from the bedding pack twice a day. While these technologies may not be practical for Ontario farms, it makes us consider how losses might be managed in the future.
After looking at feed and bedding inside the barn, the next step to manure management is storage. There is a lot of value in a manure pit or in a pile. Adam Hayter shared photos of his covered manure sheds and we estimated that a 60’ x 120’ shed can hold 1,700 tonnes of their turkey manure, which is at least $120,000 worth of just nitrogen (N), phosphorus (P) and potassium (K) at current fertilizer prices. As for dairy, it was estimated that a 160’ manure pit, 14’ deep would hold two million gallons and that would be at least $100,000 worth of NPK. However, manure is biological and begins to change immediately, depending on whether it has oxygen or not. Without oxygen, like most liquid manure pits, the storage begins to produce methane (CH4) and ammonia (NH3) among other gases, and the hotter it gets, the faster it off-gases carbon and nitrogen. As well, research is showing that the higher the pH, the faster gases leave.
There are a few solutions to slowing down nutrient loss in a pit. Covering the storage not only keeps rainwater out of the manure and increases the nutrient concentration, but it can keep it cooler. There are a few options for both permeable and impermeable covers that can minimize off-gassing. One solution is to blow straw on top of the pit .
Many of the panelists and participants on the Manure Tour have tried various manure additives that may help or hinder the microorganisms working in manure storages. Dr. Andrew VanderZaag, a researcher from Agriculture and Agri-food Canada, has had success in trials to reduce the pH and off-gassing using sulphuric acid. Dr. Claudia Wagner-Riddle (University of Guelph) has also found that emptying a manure pit before the weather turns hot reduces methane production by 25 per cent and that emptying multiple times a year can further reduce methane. Like a good yogurt or sourdough starter, previous year’s manure can inoculate the whole pit and so completely emptying the tank can also help to set back the biological process.
The other option is to make use of the methane lost in anaerobic conditions and this is what several farmers across the province have done with on-farm biodigesters. In Eastern Ontario, the Manure Tour stopped at Thurler Farms near South Mountain. There, one of the newest generations of these digesters will take their manure and that of neighbouring farms to capture the natural gas for sale and return the digestate to their neighbours for land application. This process increases the pH, reduces the carbon in the manure and makes a product that is a similar composition to finisher hog manure, with a higher proportion of fast-release nitrogen. Digestate is great for application to a living crop that can utilize this N right away but can be easily lost to either air or water if not applied at the right time.
All these options are solutions for manure in anaerobic conditions, but other farmers are changing it up and creating aerobic conditions in their storages. The Manure Tour stopped at Sigview Farms, near Moorefield, where Simon and Kristina Signer designed their new dairy barn with a compost bedding pack that is aerated daily. At the headrails, manure is stored and aerated intermittently under the slatted floor with a Dairypower system. In aerobic conditions, methane and hydrogen sulphide are not produced and the air quality in the barn is much improved. The added benefit of an aeration system is that the pit requires no further agitation before application.
In the manure pit, nutrients have their peak theoretical value, but how, when and where the manure is applied will determine the true value of manure. How soon the manure is incorporated will also make a big difference to the level of nutrients. On hot and windy days, nitrogen blows away in ammonia form, and in cold, wet conditions, it leaches away in nitrate form or is lost as nitrous oxide to the air. Similarly, the phosphorus in manure is lost through water movement in or on the soil, which is why it is never a good idea to apply manure on snow. All that to say, timing matters.
So, when is the best time to apply manure to make the most of the nutrients? For solid manure (especially solid cattle manure) where the majority of nitrogen is a slow-release form of organic nitrogen, fall application will support the next year’s crop but for manure with fast-release nitrogen, like liquid hog manure, the best timing is on a living crop, even a cover crop. On the Manure Tour, the DeVries family (Zeldenrust Farms) have had success applying liquid hog manure to winter wheat in the spring, and many were interested in side-dressing corn with manure. Farmers had success with a drag lining manure into standing corn, so long as it was before four leaf stage and the corn would stand back up again. Cadman’s Continuous Manure Application (CMA) would allow for drag-line application much later in the season and in Eastern Ontario, the Fosters (North Gower Grains) have been applying their liquid beef manure to a thousand acres of standing corn every year with a tanker on tracks and an injection toolbar. Hayter’s Farm have also applied solid turkey manure to standing corn in front of a scuffler with some success.
Nutrients can also be lost when broadcasting manure at high pressures, so injecting manure is a great way to keep both nutrients and the soil structure intact. Near Alma, Ron Bults (Pit King) showcased his manure application equipment, discussing injection and how it is time-consuming. An alternative to injection that the Van Raays (The Whole Pig, Dashwood) are having success with is a dribble bar that applies their hog manure at low pressures right at the ground level.
With a flow meter, Phil Van Raay maps the application rates on their fields and, along with frequent manure analysis, can more accurately credit the manure in his cropping system. Near Ottawa, Wilfried Raats (Raats Custom Farming) has taken the next step and has installed John Deere’s HarvestLab 3000 on-the-go manure analysis to his rig, so he can give his customers an accurate look of the NPK values as applied on the field. With this technology he also sees the importance of proper pit agitation, as the nutrients can vary widely.
The value of manure also depends on whether the soil can use it. Manure is a critical part of a healthy soil and does well in a system that supports soil health. Adrian Güntensperger is a dairy farmer near Seaforth, custom manure applicator and vice-president of OPACA. He applies manure to living cover crops in the summer after wheat and sees the added soil health benefits, and his hope is to band manure in strip-till system once he can get the right equipment. Soil health is about minimizing tillage but also reducing soil compaction and staying off wet fields in the spring as much as possible. He controls traffic on the field and runs on low tire pressures, using an on-the-go inflation/deflation technology. Compacted soils don’t allow for the air and moisture levels that soil microbiology needs to grow plants and extract nutrient from manure, so soil health matters along with the nutrient levels.
When soil nutrient levels are adequate, the best value to a farmer would be to sell or trade the manure off of the farm. Several farmers on the Manure Tour had bought or sold manure, but it was difficult to decide on the dollars and cents, because it is a market that is more driven by supply and demand so it will vary by region. In areas where there is less manure, farmers have paid half the value of the P and K, others have paid the full value of the P. In areas with more manure, and in Europe as well, some producers are paying other farmers to take their manure.
The main issue with manure is its bulkiness and that makes it expensive to travel far. Some farmers took advantage of the federal OFCAF funding to offset the costs of hauling manure to fields further away. At the Dashwood stop of the Tour, Cliff Horst (Country Custom Ag) shared a simple spreadsheet that calculated the value of manure based on real-time fertilizer prices, along with the cost to haul and apply it, in order for farmers to make their management decisions. This is a simplified version of the AgriSuite apps that OMAFRA has designed at www.agrisuite. omafra.gov.on.ca.
There is no catch-all solution to manure management. However, by making more efficient use of the nutrients in manure, farmers reduce their nitrogen and greenhouse gas emissions, but they can also save big money on fertilizer.
It is exciting to see how the industry continues to grow the technology and innovation for manure management. Farm & Food Care’s Manure Innovation videos are now available online www.farmfood careon.org/timing-matters or at opaca.net ◊