Using Drylots to Conserve Pastures and Reduce Pollution Potential

Managing horses can be a rewarding experience, but it can also be challenging. Improper pasture management of horses during the winter and early spring can adversely affect pasture quality and the environment.

Horse owners can elect to use drylots during increased rain or drought periods, when pastures need protection. Drylots are designed as permanent heavy traffic/use areas and are often used on cattle farms. They keep animals in a confined area to prevent them from damaging the entire pasture. A typical drylot would contain water sources, feeders, and mineral supplements. The area can be used for wintering animals, handling animals for medical treatments, reducing calorie intake for obese horses, and more.

Justification for a Drylot

Congregating horses around feeding and watering areas can create mud, increase soil compaction, eliminate desired vegetation, and lead to weed infestations. Simply put, overgrazing and wintering horses on pastures can be problematic in Kentucky because of the weather.

One reason is the relationship between precipitation and evapotranspiration (ET), the process of losing water from wet surfaces and vegetation due to evaporation and transpiration (water movement through plants). In early summer, plants survive by using their roots to remove water and nutrients from the soil. An intense rainfall event can produce runoff when the amount of rain exceeds the infiltration rate (speed at which water enters the soil), but this can be filtered by the existing vegetation. In late fall, precipitation begins to exceed ET, and the soil water becomes recharged.

By winter, ET has diminished, but precipitation is still occurring. The soil’s surface remains wet for longer periods, preventing it from storing more water and increasing the potential for runoff. These wet conditions reduce soil strength and allow mud to develop if the vegetation is severely grazed, trampled, or removed. Grazing too many horses on a limited area over long periods during these wet seasons creates muddy conditions for farm owners.

More important, increased traffic during wet periods increases the bulk density and reduces soil aeration, making root growth and water infiltration even more difficult.

While wintertime water movement is occurring and mud is accumulating, caretakers should supplement horses in pastures with additional feed to make up for the decrease in actively growing vegetation.

However, horses don’t stop feeding on the remaining forage. There is limited vegetation to reduce surface runoff, allowing sediment, manure, pathogens, and nutrients to flow off the soil surface and travel off-site. At this point, increased soil compaction is probably preventing absorption of water and nutrients into the soil. Meanwhile, streams are reaching the tops of their banks and removing water and contaminants from the watershed. Soil erosion, if allowed to go unchecked, can lead to environmental impacts such as the removal of soil and nutrients.

By spring, the once-green pasture is mostly bare with compacted soil. Weeds, which are very efficient at converting nutrients and sunlight into vegetative mass, now propagate in the bare areas. In the spaces used for feeding hay, a thick mat of uneaten material may have smothered the soil and vegetation. The area now holds moisture and has kept the soil temperatures cooler, preventing desired vegetative cover from re-establishing. The end results are fields with soil and nutrient losses that will require more management and money to eliminate weeds and re-establish grass.

How to Construct a Drylot

You can set up a drylot in a larger pasture area using a fenced boundary, or you can create a drylot as a hub for a series of paddocks. In either situation, horses are allowed access to the drylot through one or two gates that lead from the existing pasture or pastures. They use the area year-round to access water and supplements, as well as during the winter and early spring as a confined feeding area.

Make sure the drylot is large enough to space out gates, feed, and water and limit overcrowding that may expose horses and handlers to risk. Use farm gates to allow horses the freedom to move from the drylot to the pasture or as a means of limiting access to the larger pasture area.

Using Drylots to Conserve Pastures and Reduce Pollution Potential

Location

You can easily determine the location of your drylot depending on your paddock’s layout. Consider topography and environmentally sensitive areas when planning the location. It should be a well-drained area that is relatively flat and does not have a drainage swale or ditch running through or across it.

The logical location of the drylot would be around an area with a water source. An ideal location is on a summit or flat area on top of a hill, as long as it has some protection (structure, trees, etc.) from the wind. A summit location usually provides a long distance for any runoff to travel before it reaches a stream or waterway. Don’t place a drylot near a stream or where the drainage to a stream or sinkhole is less than 150 feet away. If a stream is nearby, consider installing a riparian area (dense vegetation along a body of water) to protect water quality.

Place the drylot away from environmentally sensitive areas but close to the horse operation. Areas near barns might already suffer from high traffic and could have heavy traffic areas installed to reduce mud. Ideally, the drylot would be placed on a summit and not adjacent to a barn, because roof runoff can have an adverse effect if allowed to flow through any part of the drylot. However, having the drylot close to the farm operations can help save time on chores. Drainage water should move off the area as sheet flow and drain into a buffer strip. Clean water should be diverted from the dry lot.

Size

When determining drylot size, make sure you’re providing adequate space for the planned number of animals to move around freely to eat, drink, and socialize. An area of at least 900 to 1,500 square feet per horse is recommended. The size depends on the age, type, size, number, and temperament of the horses as well as the area available for enclosure. Keep in mind that most horse operations that have constructed pads regret not making the sites bigger. If you have other uses planned for the pad, adjust the size of the area accordingly.

Using Drylots to Conserve Pastures and Reduce Pollution Potential

Construction

Individuals skeptical of the benefits of having horses on gravel instead of mud can opt to create an area that is only partially graveled. Construction can begin once the drylot has been justified, located, and sized. You’ll need to excavate the topsoil to construct the heavy-use traffic pad. Remove the topsoil down to a soil horizon with a higher clay content and more stable surface. Producers have used track and skidsteer loaders to excavate the soil down to a clay layer. Some producers have used plows to till the soil and make it easier for skidsteer loaders to remove it. Producers installing these areas should strongly consider where to place the spoils. They might even consider selling the topsoil removed from these areas.

After excavation, lay geotextile fabric down over the exposed soil to prevent rock from sinking into the ground and soil from moving up through the matrix. The National Resources Conservation Service (NRCS) recommends placing a nonwoven, nonheat-bonded, and needle-punched geotextile fabric under all treatment areas unless the foundation is rock or the surface treatment is concrete. The fabric should have the minimum material requirements as specified in Table 1.

A weight for the geotextile fabric is usually not specified, because the specific material features differ from one manufacturer to another. The fabric should be at least a 6 ounces/square yard weight fabric to meet the requirements listed above. Your local agriculture and natural resources extension agent, NRCS district conservationist, agricultural supply store, concrete supply store, etc., might be able to advise you on where to buy geotextile fabric.

Lay a base layer of large rock (i.e., #2 or #4) on top of the fabric, to a depth of at least 6 inches. Take caution when spreading the base layer so as not to disturb the geotextile fabric. After the base layer, spread a top layer of at least 3 inches of dense grade aggregate (DGA) over the area. This will provide a solid, stable surface for feeding in the winter. You might also want to extend the geotextile fabric and rock out past the gates into the pasture, as these areas will see heavy traffic, especially if only one entrance to the pad exists.

Fences and Gates

A wide range of fencing options exists, depending on your desires and needs. However, drylots are permanent structures and should not be constructed using temporary or electric tape materials. In a situation where the animals are crowded, it is very important to think of horse and handler safety. Avoid corners and metal T-posts. Ideally, the drylot will have a gated access from a farm road or farmstead. Gates and fences should be designed to accommodate truck and tractor access to facilitate feeding and cleaning. There should also be at least one gated access from the drylot to the remaining pasture.

Costs

The cost of installing a high-traffic area pad for a drylot will be approximately $0.80/square foot; a concrete pad would cost about $4.00/square foot.

You can reduce project costs by excavating the site yourself and possibly selling the topsoil. You can justify the costs of the project because you’re saving the money you’d typically spend renovating lost pasture and replacing lost forage. You can reduce forage losses by 25 to 50% when feeding on a drylot surface or from hay feeders placed on a drylot surface rather than from muddy surfaces. Horses placed on drylots might also lose fewer shoes in the mud, which is another savings.

Table 2. High traffic area pad costs.

ItemCost/sq. ft
Geotextile Filter Fabric$0.06
Rock Base (No. 4 Crushed Limestone)$0.25
Densely Graded Aggregate$0.14
Total Materials$0.45
Labor/Grading Work$0.35
Total Cost$0.80
Using Drylots to Conserve Pastures and Reduce Pollution Potential

Drylot Management

A drylot is typically designed to keep horses off a pasture to prevent them from harming the vegetation. When managed in this manner, the animals receive supplemental feed (hay) on the drylot until the conditions change. However, more management is required to prevent the animals from eating too much grass after being fed hay, because it could lead to colic, founder, and possibly death. Horses don’t need to spend all their time in the drylot during the winter. A good time to allow the horses to have pasture access is when the field is frozen, because they might still be able to graze without harming the paddock’s surface. Getting the horses off a gravel surface is also a good management practice when the gravel is frozen. During these times, the gravel can act as an abrasive surface that could wear and damage hooves. The chances of this occurring depend on the amount of manure and forage residue cushioning the gravel surface as well as whether the horses’ are wearing shoes. Drylots have been used as locations to provide lighting for open mares. Usually the horses are brought up from a pasture and placed under the lights before evening. This method has been used as an alternative to housing the mares in stalls through the night.

You can also use drylots to prevent or restrict horses that are overweight or susceptible to founder from eating grass pastures during certain times. On average, in Kentucky, these animals would be held off pasture from the time grass begins to grow vigorously (April) until the time it begins to slow (June) and then again when the forage begins growing again in the fall. During the remaining times, the horses can be on pasture without a significant chance that they will overeat. Another approach to managing a drylot is to allow the horses to move freely from the drylot area to a pasture through an open gate year-round. Ideally, the drylot would be set up as a hub for several pastures to provide a rotational grazing system. In this case, the drylot is used more as a heavy-traffic area pad for feeding and watering the horses. Although not considered a normal drylot, it is a useful area for managing horses and controlling mud.

Maintaining the Drylot

Drylot maintenance should include scraping up manure and unused hay on an “as needed” basis. Clean the pad periodically to prevent manure buildup and the possible mixing of manure with the rock surface. How often you need to clean the pad depends on several factors, including the number of horses, the size of the pad, how long the horses are on the pad, the amount of feeding and wasted hay, etc. When removing manure and wasted forage, try to remove as little rock from the surface as possible. Clean the areas with the highest concentration of manure and wasted forage on a regular basis. Typically, this does not involve cleaning the entire pad. If possible, store the manure in a covered structure until you can dispose of it properly. One of the best methods is land application to cropland or pasture based on crop removal rates and soil test fertility levels. Manure applications should be preceded by soil test results. All manure applications should follow the NRCS Code 590 Nutrient Management Recommendations. You can also compost the manure prior to land application. Through proper operation and maintenance, your drylot can provide a stable and secure area for winter feeding and year-round watering for many years without the need for significant repairs or additions. Maintenance may include periodically top dressing with DGA, applying moisture, and compacting the area.

Steve Higgins, PhD, Director of Environmental Compliance for the Agricultural Experiment Station with UK’s Department of Biosystems and Agricultural Engineering, and Roberta Dwyer, Roberta Dwyer, DVM, MS, DACVPM, Director of the UK Preveterinary Advising Program in UK’s Animal and Food Sciences Department, provided this information.  


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