Methodologies for In-situ Characterization of the Impact of Equine Manure Management Practices on Water Quality

Nutrient loading of nitrogen and phosphorus in runoff and water leachate threatens Florida’s environmental and water resources. Of those nutrients, nitrate (NO3) nitrogen is highly soluble and not strongly bound to soils. Consequently, nitrate is highly mobile and subject to leaching losses when both nitrate content and water movement are high.

Field Technology & Water Quality Outreach

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In 2015, Washington State Department of Agriculture (WSDA) partnered with local and state agencies to help identify potential sources of fecal coliform bacteria that were impacting shellfish beds in northwest Washington.  WSDA and Pollution Identification and Correction (PIC) program partners began collecting ambient, as well as rain-driven, source identification water samples.…

Preliminary Technical Evaluation of Three Reports by U.S. Environmental Protection Agency Region 10 on Nitrate in Water Wells, Yakima River Basin, Yakima County, Washington

The Yakima Valley is a large agricultural area where there are multiple potential sources of nitrate in groundwater.  Potential sources are intermingled, i.e., homes with septic systems are on the same properties as the dairies or adjacent to farms and/or dairies.  In 2012, Region 10 of the US Environmental Protection Agency undertook a study to source track and identify nitrogen sources in the Yakima River Basin as part of an enforcement effort focusing on dairies.…

Fate of Manure Nitrogen Applied for Grass Silage Production


Previous research conducted in western Washington State has demonstrated that when manure N is applied at rates greater than needed for grass uptake, excess N in soil in the form of nitrate-N can leach to shallow groundwater during the months of high rainfall. In a prior study, it was evident that tillage and reseeding of the cropland was a contributor to loss of nitrate–N from soil to underlying groundwater.…

Swine Manure & Aqua-ammonia Nitrogen Application Timing on Subsurface Drainage Water

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In Iowa and many other Midwestern states, excess water is removed artificially through subsurface drainage systems.  While these drainage systems are vital for crop production, nitrogen (N) added as manure or commercial fertilizer, or derived from soil organic matter, can be carried as nitrate-nitrogen (NO3-N) to downstream water bodies. …

How can I prevent leaching of nitrate into groundwater from manure applications?

Nitrate contamination of groundwater occurs when excess nitrate in the soil profile moves along with water that is moving down past the root zone of the crop. In most cases, it is not possible to keep water from moving past the roots, so the only other option for preventing nitrate leaching is to avoid having excess nitrate present in the root zone during times when leaching events are likely to occur.…