Outdoor animal lots and rain
Be sure rain is not washing manure from outdoor lots to any surface waters.
Outdoor lots are common on all types of livestock farms – all receive manure deposits and all are collecting plenty of spring rainfall.
The direct movement of lot runoff to surface water either across the surface or through basins and tiles is a problem that should be addressed promptly. Be sure to observe if the runoff travels to areas near well casings, tile inlets, drainage ditches, and other less obvious direct links to ground and surface water and immediately stop this flow and correct future problems. Movement of manure to surface waters that violates water quality standards is unacceptable and any such discharge may result in regulatory action.
There are numerous options to reduce or eliminate the risk of lot runoff. Solutions should be tailored to each farm’s location, existing facilities, financial position, and management style.
While the immediate concern is to take steps to reduce risks associated with excessive spring rainfall, planning to reduce or completely eliminate runoff may hold more opportunity to improve the situation in a profitable manner. Think about the following questions regarding the lot being addressed.
Is the lot needed? Sometimes the use of an outdoor lot is more of a tradition or a perceived need than an actual necessity for profitable animal housing.
Can the lot be reduced in size? Eliminating the lot may not be an option, but can it be made smaller? Often lots are much larger than what is necessary for maintaining profitable animal performance and well-being. For example, many older facilities have 50 to 100 feet between the barn and a fence-line feed manger. Meanwhile, Midwest Plan Service (MWPS-7) indicates the minimum space required for a mature cow feed alley is only 12 to 14 feet. In this instance, there is opportunity to significantly reduce the lot area exposed to runoff potential.
Can it be covered? Rarely is this a viable option; however, it is worth considering whether or not a roof could be constructed over the lot. Economics and practical implications such as ventilation usually reduce the likelihood of implementing this alternative.
Is clean water unnecessarily contacting the lot surface? Precipitation landing on barn roofs, driveways, and areas adjacent to animal lots is normally “clean” water. By diverting this water before it contacts the animal lot, it becomes unnecessary to treat it. Properly sized, installed, and maintained industrial roof gutters can redirect clean roof water to an appropriate alternative location. With properly installed industrial guttering, the common concern of ice slide damage can be avoided. It is equally valuable to ensure that water from adjacent driveways and other clean areas is not passing through the animal lot. Grading and diverting this water away from manure areas can prevent the need for treating this water as well.
Can lot management reduce the concentration of nutrients and pathogens in the runoff? Keep lots, whether concrete or earthen, scraped so there is less manure available for transport via runoff. A practical implication would be to scrape the lot frequently, but especially in advance of a forecasted precipitation event.
For earthen lots and high use areas of pastures, can conservation practices be implemented to reduce environmental risk? For instance, can stocking densities be reduced with either fewer animals or more area? Can rotational management of paddocks be utilized to maintain adequate vegetation? Can high use areas such as watering and feeding areas be frequently relocated and the previous site revegetated? Can a cover crop be grown in corn stalk stubble that is to be grazed?
Can the integrity of the lot surface be improved and demonstrated to minimize risk to ground water? Since soil and subsurface characteristics of earthen lots influence risk to ground water, can this risk be managed? Is an engineered, compacted clay earthen lot appropriate? Are cracks, holes, or other indications of poor integrity evident in concrete or paved lot surfaces?
For more information on this topic, read the complete article.