12 Things to Consider Before Spreading Manure this Winter

03:37PM Jan 20, 2020
winter manure application Iowa State 1
Snowmelt can cause nutrient transport from manure so careful planning is required to protect water and get the most from manure nutrients.
( Iowa State University )

In 2019, Mother Nature unleashed a wicked weather pattern that blanketed most of the Midwest throughout the entire year. A wet spring led to an even wetter summer causing harvest conditions to be dreadfully delayed late into the fall and even into the winter months. 

With crops now off the field for the majority of the country, livestock producers are starting to face a different “crappy” situation. Full manure pits.

In a recent William H. Miner Agricultural Research Institute Farm Report, nutrient management researcher Laura Klaiber touched on 12 things producers should keep in mind before breaking out the manure spreader this winter:

1. Soil moisture. According to Klaiber, poorly-drained fields are typically the first to generate runoff as snow begins to melt. Additionally, more liquid will be added to the field during application, so try to avoid oversaturating already wet fields.

2. Snow, ice and frozen soil. “Fields that were well-drained prior to frost allows for manure to infiltrate the soil,” Klaiber says. “In contrast, spreading on frozen-saturated soils is prohibited because soil that froze when the soil was saturated will have an impenetrable ‘concrete frost’ barrier that prevents manure infiltration and is therefore highly likely to be lost in runoff.”

3. Soil cover. The use of cover crops can help minimize the chance of runoff by helping to slow and filter runoff water. Try to identify these fields and spread manure here first to help reduce the risk of runoff, Klaiber suggests.

4. Slope. “Applications made at the top of a long slope tend to be less risky than those made at the top of a short slope,” Klaiber says in the Farm Report. “The base of concave slopes where water often emerges due to an elevated water table, or slopes with low permeability/ shallow bedrock, are high risk areas and should be avoided.”

5. Drainage. Be aware of fields that may contain drain tile, surface inlets, ditches or concentrated flows as these may increase the risk of nutrient loss due to their ability to increase drainage from the field. According to Klaiber, it is important to monitor drainage outlets for water contamination. 

6. Surface water. Be sure to scout for slopes that may lead to nearby surface water such as ponds or streams as runoff can be directed to these waterbodies.

7. Nearby wells. Make note of any nearby wells or karst features and avoid spread in these areas.

8. Precipitation. “Pay attention to 48-hour weather forecasts,” Klaiber notes. “Precipitation greater than 0.5 inches is likely to generate some runoff from most fields, and applications should be avoided when greater than 1 inch of rain is forecasted.”

9. Snowmelt. As temperatures begin to warm up, Klaiber advises not to spread manure when the thermometer reaches 40 ̊F for more then six hours as runoff from snowmelt is more likely to occur.

10. Consistency. Consider the consistency of the manure, Klabier warns. While all manure is subject to nutrient runoff, liquid manure with less than 5% solids is even more susceptible.

11. Application. Take time to analyze how the manure will be distributed onto the field. Klabier recommends using manure injection or incorporation to help lower the risk of loss in runoff.

12. Rate and volume. Before hitting the fields, be sure to gauge the rate of manure application and your total spreading volume. Klabier suggests possibly splitting up the number of applications on fields as well as lowering the amount of manure spread.

For more on nutrient management, read: