The Dish on Dirt

by Matt

What you put your equestrian barn or riding arena ON is as important as where you decide to put it.

The variables involved in evaluating the appropriateness of the site you’ve chosen are well understood and it’s mostly a matter of going through the process.

Structure of the soil

It may seem odd to talk about the structure of soil but what we mean, put very simplistically, is how much space there is between the granules that make up the soil and how those granules clump together. We want to know this because it affects whether or not the soil will adequately support the structure you want to build. It also determines the size of the concrete footing that will bear the weight of the walls of your structure.

The US Department of Agriculture Soil Survey provides us with a starting point. The “Web Soil Survey (WSS) provides soil data and information produced by the National Cooperative Soil Survey. It is operated by the USDA Natural Resources Conservation Service (NRCS) and provides access to the largest natural resource information system in the world. NRCS has soil maps and data available online for more than 95 percent of the nation’s counties and anticipates having 100 percent in the near future.”

The Survey tells us about the underlying formation. We can engage a geotechnical engineer to do a bearing-capacity study of the site if necessary, which may include submitting a sample of the site’s soil for analysis. All of this helps ensure a safe structure for your equine inhabitants.

Site drainage

There is more than one reason for a thorough analysis of the drainage capacity of your building site. Let’s discuss three:

  • Pasture management
  • Water infiltration rate
  • Septic systems

You’re building your barn or arena for your horses, after all. It’s their health and welfare that is most important in all aspects of equestrian building. Presumably the structure will be built adjacent to good pasturing. Will you be able to turn your horses out in the winter? Will the site drain properly after a heavy rain or snow or would your horses be standing fetlock-deep in water. Not good.

The water infiltration rate is a measurement of how quickly soil absorbs water from rainfall or irrigation. If the rate at which water is poured on the soil exceeds the soil’s infiltration rate, you get runoff or standing water.

If your barn or arena have need of a septic system, you’ll need to conduct a percolation test, or perc test. Depending on where you are building, different locales have different regulations about the installation of the septic system. But the test is conducted the same everywhere. One or more holes is drilled and filled with water. We then measure how much time it takes for the water to percolate down into the soil. In general you get a better perc in sandy soil than in soil with high concentrations of clay or where the water table is close to the surface.

How green is my pasture

Or how fertile. You pasture your horses so they can graze, among other reasons, and you’ll want to fertilze. Most fertilizer recommendations for pastures are based on the requirements for hayfields. When you harvest hay for feeding elsewhere, you carry some of the soil’s nutrients away with you. Depending on where you are, your soil may or not be able to support unfertilized hay production for very long.

Pasture fertilization must factor in other elements, such as manure and the decomposition of trampled grasses. You’re not taking the grass away; your horses are eating it where it grows.

A typical horse, weighing about 1,000 pounds, produces between 45 and 55 pounds of manure per day, or around nine tons per year. Proper manure management is essential to equine health, in and out of the stall. While spreading manure on the land can be good as fertilzer, you have to rotationally pasture your horses so that they’re not feeding where you’re fertilizing.

You can also overuse manure as a fertilizer, causing nitrogen in the form of nitrates to seep into the soil and possibly the groundwater. Many owners avoid this by having the manure taken away and then using artificial fertilizers during the time their horses are not in the pasture.

As the horses graze the pasture, they trample plant litter into the soil. This litter decomposes and feeds the soil as well.

So you can see that there are many issues with the dirt upon which your dream barn or riding arena stand. Please contact us with any questions you might have about the dish on dirt, and we’ll be happy to answer them.

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