Figure 1. Small livestock yard runoff management system.

An open lot typically has an earthen surface compacted by animal traffic. This surface needs to be shaped to a uniform grade for water drainage, so it remains relatively dry except during and immediately after rainfall. Manure typically accumulates on the surface, and decaying or decomposing manure is mixed into the soil by animal traffic, sealing the surface and reducing infiltration.

Water running off concrete pads and clean water from roofs and upslope areas can cause problems if it washes manure from the open lot surface. Contaminants in runoff water can enter ground or surface water. This risk is greatest with soils having high infiltration and percolation rates. To prevent this problem, runoff controls are essential.

Producers should collect and store runoff from holding pens for later land application. Runoff control systems collect feedlot runoff, settle out manure solids, and direct the remaining runoff water to detention ponds. Figure 1 shows a livestock feedlot runoff control system for an open lot surface. All operations with more than 300 head of beef cattle or 200 head of dairy cattle will need to put in a no-discharge system (holding pond and irrigation system), and all producers are advised to do so regardless of the operation’s size.

Feedlot Cleaning

Livestock feedlot surfaces should be cleaned regularly. The amount of manure on a livestock feedlot surface depends on the animal spacing (square feet per head), hours per day animals spend on the open lot, animal size, and type of feed ration. Cleaning and scraping once per week is preferable for dairy cattle, or once every month or two for beef cattle. Concrete surfaces are easier to clean than earthen lots. Earthen yards are usually cleaned when dry, so solids may be removed less frequently. Leave an undisturbed, compacted manure layer (1 to 2 inches thick) over the soil to provide good surface sealing. A tractor-drawn box scraper collects manure while leaving a well-graded, uniform manure surface that sheds water and dries out rapidly. Earthen yards can be cleaned only once or twice per year.

Type of Yard Surface

The area needed per animal to minimize the risk of ground water contamination depends on the type of lot surface. The area needed for a concrete surface is much less than that required for an earthen lot. The concrete area needed is a balance between traffic on the lot and the resting area provided for animals. Too small an area will make it difficult for animals to move about pens during wet conditions, while too large an area is an extra expense and generates more runoff. For dairy operations, the best protection for ground water is to confine animals to a freestall barn or roofed feeding barn.

A compacted manure layer should be maintained on an earthen open lot surface to retard infiltration and denitrify nitrate. Any adjacent concrete areas should be curbed to keep runoff from flowing off the edges of the concrete onto the earthen area.

If porous soil or fractured bedrock are close to the surface where your livestock yard is located, the surface should be paved.

Manure Storage and Utilization

In addition to the condition of livestock yards, your animal waste management plan should consider storing waste for use as fertilizer. For more information on this subject see B-6030, Reducing the Risk of Ground Water Contamination by Improving Livestock Manure Storage and Treatment Facilities, in the TEX*A*Syst publication series.

Using manure as fertilizer on improved pastures removes accumulated nutrients through the cropping system. Animal waste is a valuable fertilizer and soil conditioner. When managed properly, the nutrients in manure can be substituted for commercial fertilizers while saving money and protecting ground and surface water. Matching nutrient applications to crop nutrient needs is critical. Do not over-apply manure to land. Have your soil, manure and effluent tested so you can determine the proper amount to apply.

Abandoned Livestock Yards

In active feedlots or yards, the layer of organic matter and soil at the surface lies over compacted soil, forming a layer through which water moves very slowly. Therefore, leaching of nitrate and bacteria through the surface seal and compacted layers is not likely. However, if this manure/soil layer is removed, leaching may occur.

Abandoned yards can pose a significant ground water contamination risk. As the manure pack breaks up from lack of use, water can leach through to the ground water. If you have a permanently abandoned feedlot or corral, collect all the manure, spread the manure and soil mixture on fields, and refill the former feedlot surface with other soil material. Then, till and plant the area with a crop that uses lots of nitrogen to make use of the nitrogen released as the manure decomposes. Also remove manure from a feedlot that will not be used for an extended period. Otherwise, cracks developing in the surface may allow leaching of nitrates and salts.

Evaluation Table

The following table can be used to help agricultural producers and rural homeowners determine the risk that drinking water on a given property will become contaminated as a result of the management practices being used. For each category listed on the left that is appropriate, read across to the right and circle the statement that best describes conditions on your land. Allow 15 to 30 minutes to complete the table, and skip any categories that do not apply. Note any high risk ratings and take appropriate actions to remedy them. Strive for all low or low-moderate risk ratings.

Livestock Waste Storage: Assessing Drinking Water Contamination Risk

Glossary

Filter strip: A gently sloping grass strip planted between the livestock yard and drainage ways to streams and managed to filter runoff from the livestock yard. Influent waste is distributed uniformly across the high end of the strip and allowed to flow through the strip. Nutrients and suspended material remaining in the runoff water are filtered through the grass, absorbed by the soil and ultimately taken up by the plants. Filter strips must be designed and sized to match the characteristics of the livestock yard. A typical practice is to make the filter strip area about equal to the livestock yard area.

Infiltration: The entry of water through the soil surface.

Percolation: The downward movement of water through the soil.

Runoff control system: A combination of management practices that can be used together to prevent water pollution from livestock yard runoff. Practices may include diverting runoff from the yard or roofs, using roof runoff systems, shaping yards, using settling basins, and planting filter strips or buffer areas.

Soil drainage class: A description of the frequency and duration of periods of saturation or partial saturation that exist in soils, as opposed to human-altered drainage. Different classes are described by such terms as ‘excessively drained’, ‘well-drained’, and ‘poorly drained’.

Soil permeability: The quality that enables a soil to transmit water or air. Slowly permeable soils may have fine-textured materials, such as clays, that permit only slow water movement. Moderately or highly permeable soils commonly have coarse-textured materials, such as sands, that permit rapid water movement.

Soil texture: The relative proportions of the various soil separates (clay, sand and silt) in a soil. Described by such terms as sandy loam and silty clay.

Contacts and References

For additional information contact your county Extension agent or Natural Resources Conservation Service office.