100 years of Nebraska nitrogen

100 years of Nebraska nitrogen

Nitrogen is an essential plant nutrient but increasingly found in our water. Here is a brief history:



Background levels of groundwater nitrate are <1 mg/L nitrate-N. Historically, nitrogen fertilizer only came from plant or animal sources.
1909 Haber Bosch process developed for turning atmospheric nitrogen into inorganic ammonia.
1921 - UNL Conservation and Survey established to study Nebraska water. 1920s

Nebr. corn: 26 bushels/acre

UNL Agricultural Experiment Station begins inorganic N research.

1940 - Nitrate identified by State of Nebr. Dept. of Health as a problem in poorly built wells.

1947 - Methemoglobinemia (blue baby) in infants investigated in Nebr. Medical Journal.

First nitrate compound carcinogen research.


Nebr. Corn: 26 bu/ac

1944 - UNL Extension’s first inorganic N fertilizer soil fertility recommendations.

1946 - UNL Soil Testing Lab opened.

1947 - UNL recommends minimizing leaching loss with in-season N and efficient irrigation.

1949 - Adding N through irrigation water begins.

1951 - Research review suggests 10-20 mg/L nitrate-N limit in water used for infant formula. 1950s

Nebr. irrigated corn: 60 bu/ac; 0.5 mill acres

1952 - Center pivot manufacturing begins.

1962 - U.S. Public Health Service adopts 10 mg/L nitrate-N drinking water standard.

1965 - Nebraska Water Quality Survey by UNL CSD finds pockets above 10 mg/L, attributed to coarse soils, irrigation, inorganic N fertilizer, shallow groundwater, and livestock manure.


Nebr. irrigated corn: 80 bu/ac; 1.5 mill acres

1964 - UNL cautions “mounting evidence that many farmers are using more fertilizer nitrogen than necessary for best economic return.”

Water meters and soil moisture sensors recommended for irrigation scheduling.

1971 -NE Dept of Environmental Control (now NDEE).

1972 - Nebr. Natural Resource Districts established and widespread nitrate testing begins.

1974 - Safe Drinking Water Act adopts 10 mg/L nitrate-N maximum contaminant level.


Nebr. irrigated corn: 110 bu/ac; 1.6 lb N/bu; 2.5 mill acres; about 10% irrigated by pivot

1979 - Inorganic N fertilizer identified as main nitrate source in Central Platte.

First NRD irrigation water allocations.

1981 - UNL Extension Nitrate Task Force.

1984 - First adverse birth outcomes research.

1985 - Nebraska Natural Resources Commission study identifies growing regions impacted.

Groundwater Foundation established.

1988 - Children’s Groundwater Festivals begin.


Nebr. irrigated corn: 125 bu/ac; 1.3 lb N/bu; 5 mill acres; about a third irrigated with center pivots.

1985 - Groundwater Management & Protection Act.

1987 - Central Platte NRD first quality policies.

1989 - Bazile Triangle established in Northeast NE.

1991 - Nitrate travel timing and amount estimated.

1993 - Public Water Supplies required to provide drinking water below 10mg/L nitrate-N.

Creighton builds first reverse osmosis filtration.

1996 - CDC Report on miscarriages from nitrate.


Nebr. irrigated corn: 145 bu/ac; 1.2 lb N/bu; 0.15 inches water/bu; 5 mill acres

1992 - On-Farm Research program started.

1994 - UNL Corn Nitrogen calculator first created.

1993 - crop nitrogen sensors recommended.

1999 - nitrate leaving corn rootzone 24-42 mg/L.

2004 - International workgroup review of nitrate and health (updated 2018). 2000s

Nebr. irrigated corn: 165 bu/ac; 71% pivot; 1.0 lb N/bu; 0.14" water/bu; 4.8 mill acres

2005 - Renewable Fuel Standard for ethanol.

2010 - Int. Agency for Research on Cancer determines nitrate is probably carcinogenic.

2013 - More than 1 out of 3 Nebr. irrigated acres have groundwater exceeding 10 mg/L.


Nebr. irrigated corn: 190 bu/ac; 86% pivot; 0.9 lb N/bu; 0.13" water/bu; 5.3 mill acres

2015 - Project SENSE, sensor-based N.

2017 - UNL TAPS competition for N & irrigation.

2023 - Nitrate shown to release uranium.

EPA reopens evaluation of chronic health effects.


Nebr. irrigated corn: 205 bu/ac; 91% pivot

2023 - nitrate leaving corn rootzone 17-22 mg/L.

For the full size graphic and list of references visit: https://water.unl.edu/100-years-nebraska-nitrogen

This article was reviewed by Dan Snow and Richard Ferguson

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