Manure Storage on Horse Farms

Pennsylvania Regulations
Most states including Pennsylvania have manure storage rules and regulations. In Pennsylvania any farm that produces or accepts manure within the state must abide by these rules. The rules are in place to protect water quality since manure contains nutrients like nitrogen and phosphorus that can contaminate surface and groundwater and cause environmental harm. There are also regulations for spreading manure and managing Animal Concentration Areas like dry lots. Below we will summarize the requirements for manure storage.

A horse manure pile is usually solid material that can be stacked which is referred to as a stockpile or stack. Manure that is stacked on the farmstead i e. near the barn must be either on an improved surface meaning impermeable to water such as concrete or compacted stonedust or covered with a roof or tarp. These rules reduce the risk of rainwater picking up nutrients in the manure pile and leaching into the ground or over the ground into a waterway.
Manure that is stacked in areas other than on the farmstead must follow these guidelines
Be at least 100 feet away from sensitive areas like streams lakes ponds wetlands drinking water wells and sinkholes.
Cannot be placed in an area of concentrated water flow like a swale ditch or waterway.
Be placed on the top of a hill if possible with upslope stormwater diverted away from the pile using structures like berms ditches French drains etc..
Be placed on areas with less than 8 slope.
On an improved surface if possible.
For temporary piles that will be removed and are not on an improved surface do not place them in the same location each year. If the pile will be in place for more than 120 days the pile should be covered with a tarp.
Each of these requirements are in place to avoid nutrients leaving the

manure pile via stormwater runoff and traveling either to groundwater or surface water.
Sizing the Manure Storage
Farm managers should determine the size of the area they will need for manure storage before building to make sure storage areas will meet their needs. The size of the manure storage will depend on several factors
The number and weights of horses on the farm used to determine the total manure production
How much manure is collected and stored vs how much is left in the pasture
The amount of bedding discarded
How long between manure removals
This section will walk you through how to calculate an estimate of the waste produced on an example horse farm that has one 1000lb horse which is stalled for 16 hours and turned out for 8 hours per day. We will look at both the weight and volume of waste produced weight can be helpful if you will be applying manure to a field and need to know how much you are applying and volume is helpful for sizing the manure storage.
Manure Production
An averagesized 1000pound horse produces approximately 51 pounds or 0 8 cubic feet of manure urine feces per day. This results in about 9 tons or 290 cubic feet of manure to deal with yearly. Larger horses will produce more and smaller horses and ponies will produce less. You can estimate how much more or less by multiplying the known amounts of manure production by a factor of your horses weight when compared to the standard 1000pound horse. For example
If your horse weighs 1300 pounds
1300 lbs1000 lbs 1 3
Weight 51 pounds of manure daily x 1 3 66 pounds daily
Volume 0 8 cubic feet daily x 1 3 1 04 cubic feet daily
If your pony weighs 700 pounds
700 lbs1000 lbs 0 7
Weight 51 pounds daily x 0 7 35 7