Manure timing

When is the best time to apply manure?

That depends on the logistics of your farm, weather, and soil conditions. It is also influenced by what risks you are willing to take. Risks include:

• Lost nutrients if the manure is applied too early.
• Running out of storage for the manure.
• Reduced time for nutrients to release if the manure is applied too late.
• A wet or cold spring could delay manure application and then planting.

Spring

Pros

• Manure is available closer to when a growing crop will begin using the nutrients.
• The chance of nutrient losses is lower.

Cons

• Manure with high organic matter may have less time to break down and nitrogen release may be slower than expected.
• If soil conditions are poor, delaying manure application may further delay planting.

Recommendations

Wait until all snowmelt has occurred and the soil is completely thawed. Avoid applying on wet soil to reduce compaction.

Summer

Pros

• Can apply manure directly to a growing crop and reduce nutrient losses.
• Gives farmers another window of opportunity for applying manure.

Cons

• Need specialized equipment.
• May not be ideal for the timing of livestock operations or solid manures.

Recommendations

Inject or incorporate manure between rows of growing crops as soon as possible to maximize nutrient value.

Fall

Pro

• Manure with high organic matter may have more time to break down.

Con

• There is more time for nutrient loss, especially if soils are warm.

Recommendations

Apply after soil temperatures are below 50°F but before the soil is frozen. This will slow down the conversion of nitrogen to forms that are easily lost. Do not apply in the fall on coarse-textured soils.

Winter

Pro

• Ground is frozen, so compaction is minimized.

Cons

• Nutrients can’t soak into frozen soil; the potential for loss is extremely high.
• The chance for visible runoff from fields is highest for winter applications.

Recommendations

Do not apply in winter. If an emergency arises, apply manure at the lowest necessary rate, choose fields with little slope, maintain all required setbacks from waterways, and avoid applying right before a large snowmelt.

Reduce risks of manure application during wet weather

The following is a list of possible things you can do to limit the environmental impact of manure application during wet conditions.

Instead of land-applying

• Consider temporary stockpiling for solid manures until field conditions are better. See the MPCA rules on stockpiling.
• For liquid manure, you may want to pump the basin partially to avoid overflow, land-apply only what is necessary or find a different storage space (make sure it is permitted).
• Apply the remaining manure later in the fall under better conditions, or in the spring.
• Try to avoid winter application (on frozen or snow-covered soils) if possible.

Tips for land application in wet conditions

• Start first in the parts of the fields that have adequately dried, like higher ground.
• For better access in wet fields, fill tankers or spreaders to less than full capacity to reduce the weight of the equipment and avoid soil compaction.
• Perform tillage along contours to create furrows that will capture any manure moving down slope.
• For liquid manure, keep application rates low enough to avoid ponding or runoff during application.
• Avoid areas with slopes greater than 6 percent for solid manures and 2 percent for liquid manures.
• Stay 300 feet away from sensitive features like waterways and tile intakes. Avoid flood-prone areas.

What to do if there has been a spill from a storage basin or during land application

• Call the State Duty Officer at 1-800-422-0798.
• Take immediate action to limit environmental impacts.
  • Create temporary berms or dams to stop the spill from moving.
  • Plug culverts and tile intakes temporarily to keep manure from flowing in.
  • Soak up liquid with something absorbent, like straw, wood shavings, or hay.

Remember that producers and commercial manure haulers need to work together and be as flexible as possible in these conditions. Consider looking in your area for a neighbor that has suitable fields for land application or approved manure storage space that can take some of your excess manure.

Avoid modifying or constructing a new basin without approval from the Minnesota Pollution Control Agency (MPCA) and storing manure in unpermitted basins.

For more information about your options or help with understanding local ordinances, contact your County Feedlot Officer.