Winter 2001
Manure management assistance for open feedlots
by Paul Miller, USDA-Natural Resources Conservation Service, Des Moines
Many open feedlot operators across Iowa have registered their feedlots with the Iowa Department of Natural Resources (IDNR) and will be working with them to determine what, if any, manure runoff controls are needed for the facilities. If structures are needed a producer can receive engineering assistance from private consultants, Iowa State University Extension, or Natural Resources Conservation Service (NRCS) personnel.
The NRCS provides technical assistance in the planning, design, and construction of manure management systems by concentrating on collection, storage, treatment, and use of manure and by incorporating these components into an overall conservation system for the farm. Financial assistance may be available through state and federal cost-sharing programs to help producers implement components and practices of a manure management system. Currently, in Iowa, Environmental Quality Incentive Program (EQIP) cost-share dollars are available to feedlot owners with less than 1,000 animal units (a.u.). Current proposals in the Farm Bill discuss eliminating the feedlot size factor for cost-share eligibility requirements.
When providing technical and financial assistance, NRCS must follow their conservation practice standards and specifications. It is important to note that NRCS’s standards may be different than the requirements of IDNR.
When NRCS provides assistance on an open feedlot, they conduct an open lot system evaluation by assigning points to five categories. The point total assists the planner in determining what level of manure control or treatment is needed for the facility. The first category evaluated is the size of the operation. The larger the operation the more points that are assigned.
The second and third categories are evaluated together with the points summed. The second category is the distance to a water of the state or a tile surface intake that would receive at least part of the storm runoff from the feedlot. The distance is measured along the flow path from the feedlot to the surface water or surface intake. In this instance, the shorter distances receive the greater point values. The water use designation or surface water classification as shown in the Iowa Administrative Code is used as the third evaluation category. The higher quality water use designations will have higher points. If multiple water uses are evaluated for one feedlot site, the points for the distance and water use for each different water source are evaluated and the greatest point total is used in the overall site evaluation.
The fourth category is the distance from a feedlot to a town or city. Points are assigned only if the flow from the feedlot runs toward an urban area with more points for closer distances. The fifth category is the flow distance to a drainage well, water supply well, or sinkhole that is located such that runoff from the feedlot could directly enter or infiltrate within 25 feet of the well or sinkhole.
After the five categories are computed and added together, the point total is finalized with an adjustment factor. The adjustment factor considers the dilution effect of the drainage area adjacent to the feedlot. It is determined by dividing the watershed area, including the feedlot, above the point where the runoff reaches the water of the state by the area of the feedlot. The lower the ratio of drainage area-to-feedlot area, the higher the points that are added to the other factors.
The final point total assists the planner in determining the minimum level of manure treatment. The treatment levels include solids settling only, solids settling plus filter strip or other additional treatment, and total containment of all manure and runoff from the 25-year, 24-hour storm. NRCS uses this evaluation process to ensure adequate controls are planned to minimize manure and runoff effects on the environment and that the plan meets NRCS standards. It is important to note that the NRCS minimum standards may be different than IDNR requirements. For assistance in planning a manure management system for your open feedlot, please contact your local NRCS office. The NRCS staff can inform you of the minimum standards and let you, the producer, decide what level of assistance you need.
