There’s no debate over manure being beneficial as a soil amendment, but just what’s in the manure in terms of nutrients can cause a significant conversation. Manure isn’t always equal, even within the same type of livestock, so while applying it to crops can be a key part of yields and soil health, knowing manure’s potential nutrient contents is essential.
Manure “book values” are outdated with information coming from the late 90s and early 2000s. In 2017, Melissa Wilson, associate professor with the University of Minnesota from the department of soil, water and climate in the College of Food, Agricultural and Natural Resource Sciences, knew that things had likely changed over the course of 25 to 35, or more, years.
“How can we get more modern data” was the question Wilson began asking with colleague Erin Cortus, a fellow associate professor with U of M and extension engineer. “Some of the questions I’d get, even back then, was ‘what can I expect from different manure types?’ And the only resources we had were… you can look them up in a book.”
With the advancements in manure testing over the last two decades, along with increased focus on leaching of nutrients like phosphorus, it was natural to assume things had changed.
In talking to testing labs, Wilson found that some of them were running thousands of manure samples annually. The idea for ManureDB was born with a ready supply of data from US testing labs. Now, the database at z.umn.edu/manuredb has about 2,500 users and has had about 28,000 individual event counts since going public in July 2023.
Now, two years in, the team is anticipating adding data for 2024 soon, and is reflecting on learnings, challenges and more, including what they’ve learned about the sheer amount of data with which they’re dealing.
Half a million samples
At the start, Nancy Bohl Bormann, manure and nutrient management researcher at U of M, was tasked with setting the system up and managing the myriad details that came along. Now, she is looking at adjusting the system to make it more useful to users like researchers, farmers and agronomists.
“We’re trying to keep it updated on an annual basis,” she says. “There is no 2024 data in there yet, but hopefully in the next couple of months.”
Understandably, there is a backlog of data given the number of requests made to labs and the eventual flow of the previous year’s information.
“We have over 498,000 samples in the database,” Bohl Bormann says of the size of the database before the 2024 data is input. “We have a great amount of samples from the midwest, the southeast and northeast regions.”
The tool provides information in a way that protects source privacy. For example, state or origin is available as part of a dataset, but not if there are only one or two of a certain type of livestock producers in that state. If there were only two turkey growers in Michigan in the samples, the state wouldn’t be included in the results.
For samples to be available in the dataset, at least five samples per animal type per region per year are needed.
“We also do not show what lab it is coming from,” Bohl Bormann says.
Countries accessing the system include, dominantly, the United States, but also Canada, China, India, Brazil, Spain, the Netherlands and more, says Wilson. There is interest in adding Canadian data in the future, but because current funding is from a U.S. source, the data will be as well.
Surprises along the way
Wilson notes that perhaps the biggest surprise in inputting data and getting the system developed was learning that much of the data they were hoping for was not included in the lab data.
“We weren’t getting the storage information, the growth stage and other things,” she says. “It’s different in different areas and regions. In some areas, it seems like they have more questions on their intake forms.”
But she explains that more questions don’t necessarily lead to more answers.
“Some labs have said they narrowed down their question sheet,” Wilson says. “So people would fill it out more completely.”
Labs send the data with the percent of nutrients and the percent of moisture content which is helpful for users but needs some options applied to it. Rather than wondering what the percent of nutrients means to a manure application, the ManureDB team added the feature to change nutrient measures from percent to pounds per 1,000 gallons in a liquid manure or pounds per ton in a solid.
New features, like more visualizations, have been added in addition to these unit conversion options.
What’s driving changes?
“Some neat data visualization features are being added,” says Bohl Bormann. “You can also more easily see how many samples are available for a certain data selection in the Data Explorer tab. For example, if I select goat as an animal type, it shows there are 82 sample results.”
Ensuring the tool is intuitive is driving many of the changes forward. As she explains, livestock producers could use it for benchmarking and understanding how their manure compares to manure from other producers in their area.
“We’re slowly trying to make it more user-friendly as well,” Wilson says. “We thought it might be cool to see if there are feed relationships with trends that are going on. That’s still pie in the sky.”
There have been learnings around regional differences and she says book values didn’t account for that. However, she hasn’t had any big surprises. As expected, she did see changes in the phosphorus content in swine manure.
“Phosphorus in swine has come down. It’s actually levelled off,” Wilson says. “People had thought that had happened and we did see that in some of our averages.”
She says the past 10 to 15 years were when the levels came down, then in the last few years, that shift levelled out.
The whole menagerie
Other than typically expected animals like swine, beef and chicken, there have been a few unexpected samples.
“There’s also a lot of other things that come in from research from wildlife to zoos,” says Bohl Bormann. “In an extension, you often get interesting questions about manure. Sheep, horse, alpaca.”
Wilson rounds out the list, noting that duck, fish and insects have also made their way into the database.
“Bunnies and rats one time. Sometimes there’s deer,” she says. “All kinds of interesting things.”
While wildlife manure may not be a common search, other types are. Bohl Bormann says the database is allowing people to match available manure nutrients to their crops.
“There’s also a lot of data and manure modelling,” she explains. “Several people who are starting to use this resource want to know if they have enough land for the manure they have.”
The project is partnered with the Minnesota Supercomputing Institute and other universities are making models from the data in ManureDB says Wilson.
“We’re always interested in adding more data as well,” she says. “Other partners are welcome to reach out and work together. We’re always in talks with other groups and organizations.” •
