Source: Alberta Agriculture and Forestry
“Short-term in-field manure storage and seasonal feeding and bedding sites. What do they have in common? Surface water and the potential for nutrient accumulation in the soil, that’s what,” says Deanne Madsen, sustainable agriculture resource specialist with the Alberta government.
“When was the last time you observed surface water flow in and around your fields where manure is stored, or livestock are fed? Taking the time to note where nutrients accumulate, and surface water runs and pools on a field can be a huge benefit when determining where to locate short-term manure storages or seasonal feeding and bedding sites.”
One risk associated with storing manure temporarily in fields, or managing a seasonal feeding and bedding site, is the potential for manure constituents, such as nitrogen and phosphorus, to leave a site during runoff events. Runoff events occur because of snowmelt or heavy rains. Frozen soil increases the loss, as infiltration does not occur.
“This risk and potential impact are greater when runoff can potentially enter nearby water bodies, including lakes, irrigation canals and ditches,” says Madsen. “Too much phosphorus can degrade surface water quality by promoting algae growth, rendering the water unfit for consumption or recreational activities.”
A second risk associated with managing temporary storage sites or seasonal feeding sites is nutrient accumulation. Repeated use of a site can result in significant deposition of nutrients. This can be made worse if there are no management or cropping options for nutrient removal from the site.
High soil nutrient levels can lead to loss of valuable nutrients in runoff and result in increased downward movement of water-soluble nutrients like nitrate-nitrogen. Elevated levels of nitrate leaching into groundwater can make the groundwater unfit for consumption by animals and humans.
To prevent this, manure should be located away from places where water pools and runs off via channels leading to ditches, irrigation canals and water bodies. To prevent accumulation, rotate your temporary manure storage and feeding sites.
“Taking the time or dedicating someone to conduct a field or site environmental risk assessment can help reduce these risks and save you headaches, time and money. Benefits of assessing sites can result in operational efficiencies, as well as improve herd health, riparian function, water quality and public perception while minimizing nuisances like odours and flies.”
Completing a thorough site risk assessment will identify if any changes need to be made to management practices at the existing site or relocation of the site itself is needed. By adopting beneficial management practices (BMPs), it may be possible to mitigate or eliminate the risks to the extent that relocation may not be necessary.
Factors to consider when evaluating a site should include:
- site location – proximity to water bodies, riparian areas, water wells, springs, neighbours and recreational properties
- slope of land
- snow load
- flood potential (amount of run-on, frequency and severity)
- water erosion potential (amount of runoff, ground cover and soil texture)
- presence of and effectiveness of surface water controls (for example, ditches, berms and retention ponds)
- soil properties (soil nutrient levels, soil texture, organic matter levels and rate of water infiltration)
- crop type and production – current and future
- fertilizer and manure management history and plans
“Walking around and evaluating the site during spring melt is a great way to observe firsthand what is happening. Tools to help with the assessment such as aerial photos provide excellent visuals to help identify distances between your temporary manure storage or wintering site and sensitive areas. They can also help show how water flows through the field and if or where runoff leaves field boundaries.”
The Alberta Soil Information Viewer is a great resource that provides topographical maps and soil survey information to help identify any risks associated with land slope and soil characteristics. The Alberta Water Well Information Database provides water well reports to help identify subsurface conditions and proximity to groundwater supplies. Infrared satellite imagery or drone technology can also help you determine where the water runs or flows on your land to help you site your manure storages or seasonal feeding and bedding sites in optimal locations.
“Consider reaching out to provincial specialists and/or private consultants to help you make land management decisions. They can also help you determine if your site and management practices meet or even exceed technical or regulatory requirements,” says Madsen.
The Agricultural Operation Practices Act (AOPA) includes standards for constructing surface water control systems, short-term manure storages and seasonal feeding and bedding sites to protect water quality. See Wintering Sites and Livestock Corrals.
If you want to tackle the site assessment yourself, check out the Wintering Site Assessment and Design Tool. This tool identifies the level of environmental risk, outlines potential causes for concern and provides recommendations on BMPs to help manage the risk and protect the environment when selecting and managing a site. Alternatively, the Alberta Phosphorus Management Tool is a risk assessment tool to help producers make livestock and nutrient management decisions to minimize phosphorus losses.
“There are a variety of resources and tools available to help you identify which BMPs to implement to manage and site your temporary manure storages or seasonal feeding and bedding sites to minimize environmental risks. Taking the time this spring to observe what’s happening in your fields is a great way to support and supplement the risk assessment tools,” says Madsen.