Hayfields can be an excellent location to deliver manure nutrients, especially during the growing season when other fields are unavailable. Forage crops need the nutrients and respond well to the nitrogen delivered by manure.
But timing, rate, and the type of manure applied matter. Iowa State University professor Dan Anderson offered advice for applying manure to hay in a recent “The Manure Scoop” blog post.
For hayfields, it is best to apply manure as soon after harvest as possible. “This gives manure the greatest chance to reach the soil surface while giving the stand the most time to recover before the next harvest,” Anderson explained. This timing also cuts down on wheel traffic damage to regrowing plants.
Anderson recommended applying manure to older hay stands when possible. They tend to be more tolerant of manure application and often contain a little more grass, which responds well to nitrogen in manure.
If applying liquid manure from storage, Anderson noted that, in this case, thinner manure is better, so don’t agitate the manure fully before pumping. “This is one of the rare times in agriculture when taking only the top layer is considered good management,” he explained. The top fraction of manure is lower in solids and will spread more evenly, which is less likely to smother hay regrowth. This thinner manure is also easier on alfalfa crown.
For solid manure, apply 5 to 10 tons per acre, depending on the manure’s characteristics. Apply thick pen pack manure at the lower end of that range, as coarse bedding can create a mat on the surface of the field and shade regrowth. More decomposed manure is finer textured and spreads more easily, so it can be applied closer to 10 tons per acre. “The key is even distribution,” Anderson noted. “Many problems aren’t caused by manure; they’re caused by a pile of manure.”
Applying manure to hay ground can ease manure storage pressure, and the additional nutrients often give forage a little boost in production, adding to the benefits.
The authors are associate extension professors with the Alabama Cooperative Extension System and Auburn University.
This article appeared in the August 2026 issue of Journal of Nutrient Management on page 19.
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