Applying winter manure

Editor’s note: The following was written by Chryseis Modderman, Unviersity of Minnesota Extension manure management educator, for the university’s Minnesota Crop News website.


Here we go again — another wet fall. Many manure applicators around the state are having flashbacks to last year and bracing to face those challenges once again.

Last year, Minnesota farmers, on average, had about seven days between harvest and substantial snowfall or ground freeze in which to apply manure. And certain areas, such as southern Minnesota, had far less than that.

The problem is a struggle between minimizing runoff and logistics. If time runs out for applications, storage overflow can become a problem in the winter. Unfortunately, cows are not going to stop producing manure, so it has to go somewhere.

This was the focus of a discussion activity this past winter with commercial manure haulers: what do you do when faced with dwindling storage space, but fields are too wet or frozen/snow-covered? The goal was for participants to learn from each other, and to plum the deep well of knowledge of applicators who have seen it all.

Tips from commercial applicators:

In a wet fall, saturated fields are a no-go, especially when using a large liquid tanker. Runoff risk is high, and future compaction issues make it not worthwhile (not to mention the likelihood of getting stuck). When asked about applying in saturated soils, top responses from applicators were “pray that it stops raining” and “wait it out.”

Well, what if you get pinched between a rock and a hard place and it just won’t stop raining, and ground-freeze or substantial snowfall has occurred? Then it is time to assess storage. Specifically, how much manure needs to be moved or applied to avoid storage overflows before spring applications can be made?

First and foremost, if liquid storage is at risk of overflowing, contact the state so they are aware and can help you come up with solutions.

Storage overflow is considered a manure spill, and the appropriate response must be made. Follow clean up and reporting rules.

Solid manure is relatively easier than liquid to manage in adverse conditions because temporary stockpiles can be created to stall application. Follow the rules pertaining to placing temporary stockpiles.

Whether under wet or winter conditions, if storage is about to be tapped out, manure should be transferred to other storage facilities — if any have room — or land-applied.

In general, when conditions are dire, pollutant discharge risk is lower for land applications than a storage breach when application sites are carefully chosen. With land applications, you must do all you reasonably can do to avoid pollution from contaminated runoff.

Choosing the right application site to minimize runoff is crucial. Choose the flattest, driest fields possible. Applying to select portions of fields may be the best option. Fields with more residue and furrows will hold manure better than bare fields.

If possible, incorporate or inject the manure into the soil to lower runoff risk.

Follow setback requirements. Under winter conditions, the required setback from all sensitive features (lakes, streams, wetlands, drainage ditches, tile inlets, etc.) is 300 feet. It is also best practice to adopt this setback in wet conditions.

Make sure you are applying appropriate nutrient rates. If applying on top of snow or frozen soil, reduced application rates may be more appropriate.

Do not apply when a large rain or snowmelt event is expected in the next 24-48 hours. A great free tool to help you determine when runoff is expected is the Runoff Risk Advisory Forecast. It shows the runoff risk for the present and future days. You can even sign up for text or email alerts that tell you when runoff risk is high.

Remember, local rules may be more stringent than state rules, so make sure to know your county requirements before application.

You may have additional restrictions depending on your operation’s permit. If you have an NPDES or SDS permit, you may not be allowed to apply liquid manure after Nov. 30 unless your situation is deemed an emergency. In this situation, you must notify the state of your emergency application.

Sign up for our Daily Headlines newsletter

* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.