Manure Minute: With fertilizer prices rising, is manure an option?
December 10, 2021 by Chryseis Modderman | University of Minnesota Extension and Melissa Wilson | University of Minnesota extension specialist
The short answer: yes – as long as it works with your operation.
As fertilizer prices continue to rise, more people are considering how to integrate livestock manure into their soil fertility plans. While dealing with manure can be a bit more complicated than fertilizer, it’s a valuable source of nutrients and also provides food for soil microorganisms; a win-win situation when it comes to overall soil health. Here are some tips to consider to make sure you get the best bang for your buck from manure.
No livestock? No problem
If you don’t usually apply manure, you likely don’t have a large livestock operation; but don’t let that stop you from reaping the benefits of manure. Talk to a neighbor who raises livestock about buying some of their manure and paying them to apply it on your fields.
There are several mutual benefits from this sort of partnership. The obvious one being that you get the nutrient and soil health benefits of manure, while possibly saving a chunk of change on fertilizer; and the livestock owner earns extra money from a (by)product they needed to apply anyway. In addition, large livestock operations sometimes struggle to find enough land suitable for manure application in the fall to make their on-farm manure storage last through winter. If your fields are close to their barn, it may help cut their transportation costs. Plus, if your partnership continues in the future, they may be able to write you into their manure management plan (check out your local manure planning rules for more information).
Using a neighbor’s manure is far from a novel concept and there are many farmers that already do this every year. Unfortunately, these agreements aren’t standardized, so prices and experiences may vary. Just keep in mind that if another farmer applies manure to your field, it is now considered “transferred manure.” In most cases, the operator will give you certain records about the manure being applied that you will need to keep for up to six years after application. More details on transferred manure can be found with your local manure rules and permitting agency.
Manure nutrient availability is not always like fertilizer
Not all nutrients are created equal when it comes to manure. Some are bound to organic particles and will release slowly over the first and even the second growing seasons after application. Other nutrients are plant-available right away and behave similarly to commercial fertilizers after application. More specifically, nitrogen (N) availability of manure varies by livestock species and how the manure is applied. Your state or province should have resources that estimate N availability.
For the other nutrients, we expect that 80 per cent of the total phosphorus (P) and 90 per cent of the total potassium (K) measured in the manure via a laboratory test will be available to the crop the following growing season.
Spread it out
Since manure is a complete nutrient source, you can choose several different application rates based on your goals for the field. Typically, the N-based application rate (to supply full N needs of the following crop) is the highest you can apply in a field. This usually results in more P and K than is needed for that crop. If you are trying to get the best bang for your buck, consider applying the manure at a lower, P-based rate, and then supplement the rest of the N needs for the crop with commercial fertilizer. That way the nutrients are balanced for crop needs, and you can spread manure on more fields. Remember that manure also has carbon, which can help improve the organic matter content of your soils. Spreading the wealth to as many fields as possible can be beneficial in the long run. •