Getting more value from every load of manure

What if the first manure load hauled to a field contains significantly different nutrient levels than the last?

According to speakers during a recent Manure Manager webinar, that situation is more common than many producers realize. Without proper mixing and sampling, nutrient levels can vary throughout a manure storage, making it difficult to know exactly what’s being applied to a field.

For livestock producers facing high fertilizer costs, understanding the nutrient value of manure can help stretch input dollars and improve nutrient management decisions.

“If we just emptied it without agitating, we would end up getting very highly variable amounts of nutrients,” said Dr. Rebecca Larson, professor and extension specialist at the University of Wisconsin-Madison.

What’s in the storage may not be what’s reaching the field

Over time, manure separates. Heavier solids settle to the bottom while lighter material remains closer to the surface.

The result is a storage that may contain very different nutrient concentrations from top to bottom.

That creates challenges when manure is being used as part of a crop fertility program. If nutrient levels are overestimated, crop nutrient needs may not be fully met. If they are underestimated, producers may apply more nutrients than necessary or purchase commercial fertilizer they don’t need.

Agitation helps create a more consistent nutrient mix by bringing settled solids back into suspension before and during pumping.

Take more than one sample

A major takeaway from the webinar was the importance of collecting representative manure samples.

Larson shared research showing nutrient levels can change considerably throughout a pumping event. A sample taken from a single load may not represent the nutrient content of the entire storage.

Her recommendation is to collect multiple subsamples over the course of pumping and combine them into a single composite sample for analysis.

“Make sure you agitate before and during pumping,” she said. “Composite 10 subsamples.”

For producers hauling manure over several days, that means collecting samples throughout the job rather than taking them all at once.

Don’t skip equipment callibration

Getting an accurate manure analysis is only part of the picture.

“Calibrating your land application equipment is the most important thing you can do,” Larson said.

Knowing nutrient levels won’t help if the actual application rate differs from what was planned. Verifying gallons applied per acre or checking flow-monitor systems can help ensure nutrients are being placed where intended.

Manure has real fertilizer value

Dr. Horacio Aguirre-Villegas, scientist at University of Wisconsin-Madison, encouraged producers to view manure as a nutrient source rather than a waste product.

“Remember that your manure is money,” he said.

With fertilizer prices remaining a significant expense on many farms and ranches, knowing the nutrient value of manure can help producers make more informed fertilizer decisions.

He also noted that manure nutrient levels can change from year to year.

“What is in your manure this year is not necessarily what is going to be there next year,” he said.

Factors such as feed, bedding, weather, and storage conditions can all influence nutrient content.

Application method matters

The webinar also examined different manure application methods, including surface application, incorporation, and injection.

While management goals and equipment availability often determine which approach is used, incorporation and injection can help retain more nitrogen by reducing exposure at the soil surface.

Low-disturbance tools such as dribble bars can also help reduce nutrient losses while placing manure close to the soil surface.

Safety remains critical

Both presenters stressed the importance of manure gas safety during agitation.

Hydrogen sulphide, methane, and ammonia can be released when manure is mixed, creating dangerous conditions around storages and pits.

Larson encouraged producers to use gas monitors and avoid relying on smell alone as a warning sign.

“You think the concentration has gone down, but it has not,” she said. “It may have increased to a point getting closer to where it could cause loss of life.”

Keeping people away from agitation areas and following safe operating practices remains essential whenever manure is being moved.

Takeaways for producers

The webinar’s message was simple: getting the most value from manure starts before the first load reaches the field.

Agitating thoroughly, collecting representative samples, calibrating application equipment and prioritizing safety can all help producers make better use of the nutrients already available on their operations.