Manure Minute: Stockpiling, siting and sizing, oh my!
April 29, 2020 by Chryseis Modderman
Sometimes we get bogged down in the intricacies of manure and farm management. At these times, it’s refreshing to take a step back and be reminded of the basics. On-farm manure stockpiling doesn’t need to be complicated, but there are a few important things to keep in mind. Here are some things to consider when it comes to manure storage and stockpiling.
Stockpile site selection
As it is in real estate, stockpiling is all about location, location, location.
The ideal stockpile location is out of the way, can be accessed with hauling equipment, and will not lead to runoff into sensitive features. A flat area, outside of areas that flood, with a non-permeable base to avoid leaching is best. And, try to be considerate of your down-wind neighbors.
Clean water from rain, roofs, or uphill areas should not be allowed to pool around or run through a manure stockpile, as any water that comes in contact with the manure will carry away pollutants.
Soil berms may be built to divert rain and uphill water, and gutters and downspouts can be added to barns and buildings to divert water.
Once you have the perfect location picked out, it’s time to think about what the storage area will look like. First, to determine how much space is needed, ask yourself the following questions:
- How many animals will contribute to the manure stockpile?
- How much, and what kind of bedding will be in the manure?
- How long will the stockpile remain before being hauled away?
For example, let’s say you’re a horse owner. With manure and bedding, a 1,000-pound horse can produce 60 to 70 pounds of waste per day, occupying around 2.4 cubic feet. If you have five horses that each weigh exactly 1,100 lbs., that’s 5,500 lbs. total. You haul away your manure twice per year – once in the spring and again in the fall.
You know that an average of 2.4 cubic ft. of manure is produced each day per 1,000-lb. horse. So how much space will you need for manure storage?
Making the calculations
The formula: 2.4 cubic ft. x (5,500 lb. / 1,000 lb.) x 365 days = 4,818 cubic ft. per year
But, you haul manure twice per year, so you really only need storage for half of a year
The final calculations: 2.4 cubic ft. x (5,500 lb. / 1,000 lb.) x 182.5 days = 2,409 cubic ft. needed.
Putting it all together
Does this mean you should build a storage pad that is exactly 2,409 cubic feet? No. These calculations were based on averages to give you an idea of the size needed. Actual space allotted for storage should be larger than the calculated value to account for variability. For one, you will likely not haul the manure away at exactly 182.5 days, and you need to ensure that you’ll have enough storage if it is a long winter. And the actual manure and soiled bedding might vary based on the horse or bedding type.
It’s always best to err on the side of having too much space for manure, rather than cutting it close. That way, if you change bedding or add animals, you won’t need to expand your storage size.
Chryseis Modderman is a Crops Extension Educator with a focus on manure nutrient management at the University of Minnesota. Read her previous Manure Minute columns online at www.manuremanager.com.
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