The Do's and Don'ts of In-Field Manure Stacking

In-field manure stacking involves temporarily stockpiling solid manure in a crop field on an unimproved surface in a windrow or cone-shaped pile. There are several scenarios where it may make sense to stack solid manure in a crop field. When importing solid manure, it is convenient to temporarily stack it in a field close to where it will be land-applied. It can also be beneficial to field stack manure while waiting for ideal land application conditions, such as avoiding winter manure applications.

Manure that has been stacked in-field must be land applied by the next growing season or within 120 days of stack formation, whichever occurs first. If you know that you will need to stack manure in-field for a longer stretch of time, covering the pile with an impermeable cover within three weeks of stack formation negates this time requirement. Covering manure stacks has other benefits, such as reducing odor, reducing leaching of nutrients, improving handling when it comes time to land apply the manure, and helping to control fly larvae and pupae.

Below are additional guidelines that must be followed to stack manure in-field in Pennsylvania. This includes manure produced at your own operation and manure imported into your operation. This does not apply to manure stacked on an improved/impermeable surface, manure and/or mortality composting, or emergency-related manure stacking.

• Do indicate in-field stacking locations on the operation maps in your Act 38 Nutrient Management Plan or Manure Management Plan. These stacking locations should be rotated so that a manure stack does not occupy the same footprint more than once in a four-year period.
• Do shape the stack in a cone or windrow to shed rainwater. This does not apply if the stack is covered with an impermeable cover within three weeks of stack formation.
• Don't stack within 100' of surface water, sinkholes, or wells.
• Don't stack within water concentration areas or where the seasonal high-water table is less than 3 feet.
• Don't stack in areas with excessively drained soils. This does not apply if the stack is covered with an impermeable cover within three weeks of stack formation.
• Don't locate manure stacks above subsurface drain tiles. This does not apply if the stack is covered with an impermeable cover within three weeks of stack formation.
• Do stack on slopes less than 8%. These would be soils listed with "A" or "B" slope class designation on a soil survey map.
• Don't stack manure near the bottom of a slope. More than 100 feet of slope above the stack increases the risk of water running onto the stack.
• Do construct a diversion uphill if a stack is located further than 100 feet from the top of the slope when the slope is 3-8%.
• Do stack manure that is dry enough to stack at least 4 feet high. Manure that will not stack to 4 feet in height can be considered a slurry, and not solid manure.
• Do limit the amount of manure stacked to the amount needed to land-apply on nearby fields.

In-field manure stacking can provide much-needed flexibility for an operation, especially when environmental conditions do not favor land application. By adhering to these guidelines, any effects on the environment can be greatly minimized.

For more information on manure nutrient management, please visit the Nutrient Management Education Program page.