"New/February 1991/10M.""Water Quality.""Focus area : nutrients and bacterial wastes.""Nitrogen in the environment.""The initial draft was written by Karen DeFelice, former associate extension agronomist; Nyle Wollenhaupt, former state extension agronomist; and Daryl Buchholz, state extension agronomist. This material is based upon work supported by the United States Department of Agriculture, Extension Service, under special project number 89-EWQI-1-9203.""Published by University Extension. University of Missouri-Columbia.

Buchholz, Daryl

DeFelice, Karen

Killpack, Scott

Wollenhaupt, Nyle

University of Missouri: MOspace

Focus Area NutrientsWater Bacterialn Quality and Wastes PUBLISHED BY UNIVERSITY EXTENSION, UNIVERSITY OF MISSOURI-COLUMBIA - Nitrogen in the'Environment ­Nitrification Scott Killpack and Daryl Buchholz, Extension Agronomy Many organisms live in the soil. Some of these are able to change ammonium nitro­gen (NH4+) to nitr~te nitrogen (N03-). This process is called nitrification. Nitrification has two steps, ,both are carried out by bacteria that live in the soil. Common sources of ammo­nium in the soil result from decaying plants and organic matter, or ammonium can come from the application of manures or nitrogen fertilizers. The Nitrification Process Step 1 Step 2 Soilrrrlcroorganisms called nitrosom.onas SoilrrrlcroorganisIns called nitrobacter amm.onia to nitrite nitrite to nitrate When Does This Happen? Nitrification depends on microorganisms. Factors such as organic matter, water content, oxygen supply, temperature and pH of the soil can affect how much, or how little, ammo­nium (NH4+) is converted to nitrate (N03-). Warm moist soils, with good oxygen supply, provide favorable conditions for nitrification to take place. Practically speaking, nitrificatiol is very active during the spring and summer months, slows in the fall and is essentially nonexistent during the winter. Impact to Water Quality The process of nitrification can have a direct impact on water quality. The end result of nitrification, nitrate (N03-), is a form a nitrogen that is highly mobile and easily moves with water. When rainfall is heavy, nitrates can move downward in the soil. Whether nitrates continue to move downward, and into groundwater, depends on underlying soil and/or bedrock conditions, as well, as the depth to the groundwater itself. If the depth to ground­water is shallow and the underlying soil is sandy, the potential for nitrates to ,enter ground­water is relatively high. However, if the depth to the groundwater is deep, and the underly­ing soil is heavy clay, groundwater contaminati?n from nitrates is not likely. $0.25 WQ254 Printed with Soy Ink on Recycled Paper Archive versio --See xtenion.missouri.eduNitrates that do enter groundwater can originate from a variety of sources. Good manage­ment practices can reduce the potential of nitrates from animal manures and nitrogen fertil- . izers getting into the groundwater. Applying manures and nitrogen fertilizers when crops are actively growing and using nitrates for growth and development, will reduce the amount of nitrate in the soil system. That reduces the amount that could potentially be moved into groundwater. However, little can be done to minimize the movement of nitrates into groundwater that result from the ongoing decay of organic matter in the soil. The presence of nitrates in the soil can simply be the result of natural bacterial-decay of organic J matter. Once nitrates get into the groundwater, the greatest concerns are for infants, less than one_ year old, and for young and pregnant animals. High levels of nitrates can be toxic to new­borns causing anoxia, or internal suffocation. Seek alternative water sources if nitrate levels exceed the health standard of 10 ppm nitrate-N. Do not boil water to eliminate nitrates. It increases nitrate levels, rather than decreases them. The most common symptom of nitrate poisoning in babies ts a bluish color to the sJ<in, particularly around the baby's eyes and mouth. These symptoms of nitrate toxicity are commonly referred to as the "blue-baby" syndrome. The initial draft was written by Karen DeFelice, former asso~iate extension agronomist; Nyle Wollenhaupt, former state extension agronomist; and Daryl Buchholz, state extension agronomist. This material is based upon work supported by the United States Department of Agriculture, Exten­sion Service, under special project number 89-EWQI~1-9203. • Issued in furtherance of Cooperative Extension Work Acts of May 8 and June 30, 1914 ~)lUniversity in cooperation with the United States Department of Agriculture. Gail L. Imig, Director, ~Extension Cooperative Extension Service, University of Missouri and Lincoln University, Columbia, UNIVERSITY OF MISSOURI Missouri 65211.• An equal opportunity institution. COLUMBIA WQ254 NewIFebruary 1991110M 

Nitrification (1991)

"New/February 1991/10M.""Water Quality."" Focus area : nutrients and bacterial wastes.""Nitrogen in the environment.""This publication was written by Karen DeFelice, former associate extension agronomist; Nyle Wollenhaupt, former state extension agronomist; and Daryl Buchholz, state extension agronomist. This material is based upon work supported by the United States Department of Agriculture, Extension Service, under special project number 89-EWQI-1-9203.""Published by University Extension. University of Missouri-Columbia.

Focus Area NutrientsWater Bacterial Wastesn Quality and PUBLISHED BY UNIVERSITY EXTENSION, UNIVERSITY OF MISSOURI-COLUMBIA - Nitrogen in the Environment ­Denitrification Scott Killpack and Daryl Buchholz, Extension Agronomy Soil microorganisms need oxygen for fuel. When the soil is very wet, water fills in the spaces between soil particles. This leaves very little room for oxygen. Some soil microorgan­isms can get the oxygen they need from the oxygen portion of the nitrite (N02-) and nitrate (N03-) forms of nitrogen. When this happens, nitrogen (N2) and nitrous oxide (N20) gas are formed. These gases return to the atmosphere and there is a net loss of nitrogen from the nitrogen cycle in the soil (see WQ252). This is called denitrifi~ation. Two main factors influence denitrification: 1) the oxygen supply in the soil 2) the soil microorganisms D oxygen particlesoxygenoo JSoil Graphics by Karen DeFelice Anything that changes these two factors will change how much nitrogen is lost and how fast this happens. These factors include the amount of organic matter, soil water content, soil oxygen supply, soil temperature, soil nitrate levels, and soil pH. A small amount of denitrification can be found taking place in soils all the time. Denitrifica­tion becomes significant when the soil is waterlogged for 36 hours or more. The longer the soil is waterlogged the greater the potential loss of nitrogen from the soil system. Impact to Water Quality The conditions which cause denitrification can have positive as well as negative implications to water quality. The positive implication is that denitrifi<;ation converts nitrates (N03-) to nitrogen gas, resulting in a net loss of nitrate from the soil system. The negative aspect of denitrification is that it takes place in soils that are waterlogged. In this situation water will move downward in the soil. Because nitrate can move easily with water, nitrate can move below the root zone of plants and potentially on down into groundwater. $0.25 WQ255 Printed with Soy Ink on Recycled Paper Archive version -- Se extenson.missouri.eduWhether nitrates continue to move downward, and into groundwater, depends on underly­ing soil and/or bedrock conditions, as well as depth to groundwater. If depth to groundwa­ter is shallow, and the underlying soil is sandy, nitrates will likely enter groundwater. How­ever, if depth to groundwater is deep and the underlying soil is heavy clay, groundwater contamination from nitrates is not likely. In some soils dense hardpans may be present, in which case nitrate movement will not progress beyond the depth of the hardpan. In these kind of soils, nitrate is more likely to undergo denitrification than move into groundwater. Once nitrates get into the groundwater, ~he greatest concerns are for infants, less than one year old, and for young and pregnant animals. High levels of nitrates can be toxic to new­borns causing anoxia, or internal suffocation. Seek alternative water sources if nitrate levels exceed the health standard of 10 ppm nitrate-N. Do not boil water to eliminate nitrates. It increases nitrate levels, rather than decreases them. The most commoJ.1 symptom of nitrate poisoning in babies is a bluish color to the skin, particularly around the baby's eyes and mouth. These symptoms of nitrate toxicity are commonly referred to as the '1Jlue-baby" syndrome. The initial draft was written by Karen DeFelice, former associate extension agronomist; Nyle Wollenhaupt, former state extension agronomist; and Daryl Buchholz, state extension agronomist. This material is based upon work supported by the United States Department of Agriculture, Exten­sion Service, under special project number 89-EWQI-1-9203. -U-n-iv-e-,-s-it-y--.-Is-SU-e-d-in-fu-rt-h-er-a-nc-e-o-f-C-oo-p-e-ra-ti-v-e-Ex-t-en-s-io-n-w-o-r-k-A-c-ts-o-f-M-a-y-8-a-nd-Ju-n-e-30-,-1-91-4~ in cooperation with the United States Department of Agriculture. Gail L. Imig, Director, Extension Cooperative Extension Service, University of Missouri and Lincoln University, Columbia, ~ UNIVERSITY OF MISSOURI Missouri 65211.• An equal opportunity institution. COLUMBIA WQ255 New/February 1991/10M 

Nitrification (1991)

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