Agricultural Irrigation & Water Quality

Agricultural Irrigation & Water Quality

Research has shown that concentrations of nitrate - nitrogen have accumulated in the groundwater beneath areas where irrigation is intense and where the soils are permeable allowing for leaching of nitrogen fertilizer. Leaching is most severe for surface irrigation systems used to irrigate sandy soils. The Platte River Valley and Eastern Sandhills have been most severely affected.

Preventing further water quality degradation or improving water quality requires careful irrigation management along with proper fertilizer management. Go to the Crop Production: Nutrient Management and the Animal Manure Management sections of this website for further information on fertilizers and nutrients.

Nitrate-Nitrogen Concentrations in Groundwater

The concentration of nitrate-nitrogen is shown in the following figure. The concentration expressed as milligrams/liter (mg/L) is the same as parts per million (ppm). The safe drinking water standard for public water supplies is 10 ppm (or 10 mg/L) of nitrate-nitrogen. Water quality is most severely affected in the Platte River Valley and in the Eastern Sandhills region. Preventing further water quality degradation or improving water quality requires careful irrigation management along with proper fertilizer management.

Average Nitrate-Nitrogen Concentration after 1989

Nebraska Extension & Regional Publications

Agricultural Nitrogen Management for Water Quality Protection in the Midwest: a Heartland Regional Water Coordination Publication, RP189
An overview of factors influencing nitrogen loss to ground and surface waters in the four-state Heartland region of Iowa, Kansas, Missouri and Nebraska, including nitrogen in the environment and the implications of agricultural nitrogen management practices for nitrogen loss to ground and surface water.

Agricultural Phosphorus Management and Water Quality Protection in the Midwest: A Heartland Regional Water Coordination Publication, RP187
A resource for nutrient management planners on the risk of phosphorus delivery to surface waters, assessment of this risk, and management options to reduce this risk; targeted to U.S. EPA Region 7 comprised of Iowa, Kansas, Missouri and Nebraska.

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