Nitrate in Nebraska

Nitrate

What is Nitrate and where does it come from?

Katie Pekarek, Water Quality Extension Educator, University of Nebraska & Crystal Powers, Research and Extension Communications Specialist, Nebraska Water Center

Nitrogen is a valuable fertilizer source that keeps Nebraska growing abundant landscapes and crops. Nitrogen that does not get used by the crop ends up in our streams, lakes and groundwater. Nitrate is the most common form of nitrogen found in water.

Impacts (Health, Economic, and Recreation)

Nitrate in Nebraska waters has economic, recreation, and health impacts for all of our citizens.

  • Farmers recognize the economic and opportunity loss of nitrogen that is not utilized for growing crops.
  • Millions of tax dollars are managed by Natural Resources Districts, Cities, and conservation agencies to prevent and treat nitrate contamination of water annually.
  • Nearly 1 in 5 Public Water Supplies and private wells in Nebraska consitantly tests high for nitrate-nitrogen.  This number is growing. (NDEE Groundwater Report, Risk and Cost Assessment of Nitrate Contamination in domestic wells).
  • Nitrate is a significant contributor to the presence of Harmful Algal Blooms (HABs). Public beaches in Nebraska are monitored for HABs and closed if the level gets to high.  
  • Long term exposure of high nitrate levels can harm fish and their habitats as the result of excessive aquatic plant growth, modified pH, and lowered dissolved oxygen levels.
  • Research has long shown that nitrate exposure is a hazard for infants.  Emerging research has demonstrated strong links with high nitrate concentrations in drinking water and lifetime risk of negative birth outcomes, thyroid disease, and certain cancers (Reference). The drinking water standard for nitrate in water is 10 mg/L.

Rust-stained irrigation pipes hint at lack of nitrate in groundwater

rusty irrigation piping
According to study from Department of Natural Resources researchers, irrigation pivots stained with rust may indicate the absence of nitrate in the groundwater supplying the pivots. This information can potentially be used to help screen for areas for the potential absence of nitrate and, in an ideal world, could indicate areas at higher- or lower-risk for nitrate contamination before it becomes a problem.

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Rural Nebraskans Voice Water Quality Concerns

Photo Credit: Craig Chandler | University Communication and Marketing

A majority of respondents to the 2022 Nebraska Rural Poll indicated they were at least somewhat concerned about contaminants in their water supply that could impact their own or their family’s health. About 45% reported they had had their water tested for nitrates, E. coli, lead, pesticides or other contaminants.

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Using Broadcast Interseeding of Cover Crops as a Tool for Water Quality Improvements

Cover crops are a proven method for increasing soil health by reducing soil erosion, increasing soil organic matter, and improving soil structure. Cover crops also have the potential to positively impact water quality by reducing nitrate leaching and nutrient runoff. While cover crops are growing in popularity in Nebraska, there are significant planting challenges. To address these challenges, interseeding has been proposed as an alternative planting method to increase cover crop success.

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Using a Cornstalk Nitrate Test to Evaluate Nitrogen Management Decisions

cornstalk sample cutting
At the end of the season, a nitrate test can help determine whether the crop was under-, adequately or over-fertilized with nitrogen, resulting in the potential to significantly reduce input costs.

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Another Dry Year: What to Know About Leftover Nitrogen in Soil Following Dry Conditions

departure from normal precipitation 2022
With the two consecutive dry seasons in 2021 and 2022, there is likely a considerable amount of unused nitrogen left in the soil, which could be used for the 2023 crop. With the higher fertilizer prices, such fertility adjustments for next crop can be profitable as well as environment friendly. So, it is recommended to test your soil and account for all sources of nutrients for the next crop.

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