For the first time since 2019, the Midwest is mostly clear of drought advisories, according to the U.S. Drought Monitor. In fact, May was one of the wettest months on record for Iowa, Minnesota, Wisconsin and South Dakota and regions of Michigan, with above-normal precipitation continuing throughout the growing season.
“The last time we had more widespread really wet conditions was in 2018 and 2019,” says Kevin Erb, conservation professional training program manager for University of Wisconsin Extension. “This year, some couldn’t get corn planted on time, and first- and second-crop hay were taken at the same time.”
Such weather has dairy producers in a pinch to manage manure appropriately.
“The key thing right now is knowing how full your manure storage actually is,” Erb says. “There’s a difference between how full it is and how full it should be.”
Manure storages have a design capacity that may be full at the top of the lagoon or a few feet below if the top is topsoil and not engineered to be saturated.
Erb suggests checking the storage capacity weekly, then immediately after a rain event and again a day later. Rainfall and runoff fill the storages quickly, as does more manure if milk production is up in the herd year over year.
If storage is at capacity, or nearing it, here are ways to effectively manage the contents before the traditional fall hauling season gets underway.
1. Put the manure storage on a diet
There are several ingredients that can make up the contents of a manure pit on a dairy, including heifer manure, feed waste and wastewater from the barn.
Secondary storage locations on, off the farm
Consider a secondary location on-site to store dry heifer manure and feed waste so the lagoon can be used strictly for liquid manure.
“If you have an option to store those things elsewhere that’s temporary and safe, that’s what you should be doing,” Erb says. “If you don’t have those options, start thinking about where you could go with it.”
Depending on permits and regulations, some producers may be able to haul this additional waste to another farm location if the secondary site is no longer using their manure storage.
“In Wisconsin, during really wet years, we’ve had people truck manure 20 to 30 miles to another farm that doesn’t have cows,” Erb says. “But if you do use someone else’s manure storage, you need to have it signed off by the person who issues permits for manure storage in your county to make sure the pit was engineered properly.”
Partner with neighbors
A written agreement needs to be developed if a producer is working with a neighboring farm site, whether that secondary location does or does not have cattle. This agreement should include how much manure was added to the site and who is responsible for removing it when the lagoon is full.
Take photos or videos to document the conditions of the lagoon before and after manure is stored there.
“Whether it’s on the back of a napkin or a formal document, make sure everybody has a good understanding of who’s responsible for what,” Erb says.
From a biosecurity perspective, the contract may also include the route in which trucks hauling manure should enter and leave the farm.
“If I’m moving manure into somebody else’s manure storage, I don’t want trucks or tractors from my farm going through their barnyard,” Erb says. “So it may involve coming around the back of the buildings and offloading through a different way. Keeping vehicles away from where cattle are is vitally important.”
Gauge water use
Critically look at water use on the dairy and opportunities to use the resource more wisely, particularly in the parlor and flush system of the barn.
“Work with employees to make sure they understand the importance of not only getting things clean but doing it in the most water-efficient manner possible,” Erb says. “Every gallon we use in the barn is a gallon we have to haul. It’s also a gallon less capacity we have for actual manure.”
2. Evaluate fields for early land application
If the storage is at capacity and land application is necessary, evaluating the fields and choosing the best location for field application is crucial. Find a location that has a lower risk of runoff to reduce the chances of water contamination, especially with the greater risk of manure reaching drain tiles in wet conditions when the manure solids content is less than 2.5%.
“Try pumping off the more solid-type manure, the heavier solid stuff because the risk of movement downward is going to be lower if the solid content is higher,” Erb says.
To retain solids content, remove the manure closest to the barn where the solids content is highest, avoiding the third-stage lagoon. Also, consider no agitation.
Inject or top-dress fields
Shallow injection and top-dressing fields during the growing season is acceptable.
“The key is to think about how we can spread manure at different times of the year,” Erb says. “I think we’re going to see more people looking at this from an environmental and crop production perspective, not just because the season is wet.”
When applying manure, consider applying manure in strips rather than the entire field. This provides an opportunity to cover the remaining areas in another application, if necessary.
Top-dressing manure on hayground with a dragline after cutting helps producers buy storage capacity if it’s applied correctly. Producers could also consider applying manure now before establishing a cover crop or summer seeding alfalfa. And applying manure on corn fields is suitable if the crop has not reached the V4 stage.
Consider future nutrient needs
Dairy producers should work with their agronomist and crop consultant to track nutrient availability on the fields where additional manure has been applied.
“If we’re putting manure on in July, a good portion of the available nitrogen is not going to be there 11 months from now when next year’s corn crop needs it,” Erb says. “Putting it on a hayfield is the best option at this point. Just be aware of an increase in potassium concentration of the next cutting.”
Increased potassium levels in forages may cause milk fever and ketosis issues, particularly in the freshening animals.
There are a variety of plan B options for producers whose manure storage is at or nearing capacity. Monitor local precipitation closely and consider these alternative practices to manage manure on the farm.
