Editing Fertilizer (section)

===Water===
{{Main|Eutrophication}}
[[File:Aquatic Dead Zones.jpg|thumb|Red circles show the location and size of many [[Dead zone (ecology)|dead zones]].]]
Phosphorus and nitrogen fertilizers can affect soil, surface water, and groundwater due to the dispersion of minerals<ref name=":03" /> into waterways due to high rainfall,<ref name=":0">{{Cite journal |last1=McKay Fletcher |first1=D. M. |last2=Ruiz |first2=S. A. |last3=Dias |first3=T. |last4=Chadwick |first4=D. R. |last5=Jones |first5=D. L. |last6=Roose |first6=T. |date=2021-02-20 |title=Precipitation-optimised targeting of nitrogen fertilisers in a model maize cropping system |url=https://www.sciencedirect.com/science/article/pii/S0048969720375823 |journal=Science of the Total Environment |language=en |volume=756 |pages=144051 |doi=10.1016/j.scitotenv.2020.144051 |pmid=33280884 |bibcode=2021ScTEn.75644051M |s2cid=227522409 |issn=0048-9697}}</ref><ref>{{Cite web|url=https://www.agric.wa.gov.au/high-rainfall-pastures/environmental-impact-nitrogen-and-phosphorus-fertilisers-high-rainfall-areas|title=Environmental impact of nitrogen and phosphorus fertilisers in high rainfall areas|website=Agriculture and Food {{!}} Department of Primary Industries and Regional Development |language=en|access-date=2018-04-09}}</ref> snowmelt and can leaching into groundwater over time.<ref>{{Cite web |title=The Sources and Solutions: Agriculture |url=https://www.epa.gov/nutrientpollution/sources-and-solutions-agriculture |archive-url=https://web.archive.org/web/20230405023648/https://www.epa.gov/nutrientpollution/sources-and-solutions-agriculture |archive-date=5 April 2023 |access-date=2023-05-04 |website=US Environmental Protection Agency |date=12 March 2013 |language=en}}</ref> Agricultural run-off is a major contributor to the eutrophication of freshwater bodies. For example, in the US, about half of all the lakes are [[eutrophic]]. The main contributor to eutrophication is phosphate, which is normally a limiting nutrient; high concentrations promote the growth of cyanobacteria and algae, the demise of which consumes oxygen.<ref name=UllmannEnv/> Cyanobacteria blooms ('[[algal blooms]]') can also produce harmful [[Eutrophication#Toxicity|toxins]] that can accumulate in the food chain, and can be harmful to humans.<ref name="toledo">{{Cite web |url=http://www.toledofreepress.com/2014/08/02/do-not-drink-water-advisory-issued-for-city-of-toledo/ |title=UPDATE (9:30 a.m.): Do-not-drink water advisory lifted for City of Toledo &#124; Toledo Free Press |access-date=5 August 2014 |archive-url=https://web.archive.org/web/20140805005647/http://www.toledofreepress.com/2014/08/02/do-not-drink-water-advisory-issued-for-city-of-toledo/ |archive-date=5 August 2014 |url-status=dead }}</ref><ref>{{cite journal |pmc=3709275|doi=10.3390/toxins5050992 | pmid=23676698 | volume=5 |issue=5 |title=Variations in the microcystin content of different fish species collected from a eutrophic lake |year=2013 |journal=Toxins |pages=992–1009 | last1 = Schmidt | first1 = JR | last2 = Shaskus | first2 = M | last3 = Estenik | first3 = JF | last4 = Oesch | first4 = C | last5 = Khidekel | first5 = R | last6 = Boyer | first6 = GL|doi-access=free }}</ref> Fertilizer run-off can be reduced by using weather-optimized fertilization strategies.<ref name=":0" />

The nitrogen-rich compounds found in fertilizer runoff are the primary cause of serious oxygen depletion in many parts of [[ocean]]s, especially in coastal zones, [[lake]]s and [[river]]s. The resulting lack of dissolved oxygen greatly reduces the ability of these areas to sustain oceanic [[fauna]].<ref>[https://www.nytimes.com/2008/08/15/us/15oceans.html "Rapid Growth Found in Oxygen-Starved Ocean 'Dead Zones'"], NY Times, 14 August 2008</ref> The number of oceanic [[Dead zone (ecology)|dead zones]] near inhabited coastlines is increasing.<ref>{{cite web |author=John Heilprin, Associated Press |url=http://dsc.discovery.com/news/2006/10/20/deadzone_pla.html |title=Discovery Channel :: News&nbsp;– Animals :: U.N.: Ocean 'Dead Zones' Growing |publisher=Dsc.discovery.com |access-date=25 August 2010 |url-status=dead |archive-url=https://web.archive.org/web/20100618192917/http://dsc.discovery.com/news/2006/10/20/deadzone_pla.html |archive-date=18 June 2010 }}</ref>

As of 2006, the application of nitrogen fertilizer is being increasingly controlled in northwestern Europe<ref name=VanGrinsven2012>{{cite journal|last1=Van Grinsven|first1=H. J. M.|last2=Ten Berge|first2=H. F. M.|last3=Dalgaard|first3=T.|last4=Fraters|first4=B.|last5=Durand|first5=P.|last6=Hart|first6=A.|last7=Willems|first7=W. J.|title=Management, regulation and environmental impacts of nitrogen fertilization in northwestern Europe under the Nitrates Directive; a benchmark study |journal=Biogeosciences |date=2012 |volume=9 |issue=12 |pages=5143–5160 |doi=10.5194/bg-9-5143-2012 |bibcode = 2012BGeo....9.5143V |doi-access=free|hdl=1854/LU-3072131 |hdl-access=free }}</ref> and the United States.<ref>{{cite web|title=A Farmer's Guide To Agriculture and Water Quality Issues: 3. Environmental Requirements & Incentive Programs For Nutrient Management|url=http://www.cals.ncsu.edu/wq/wqp/wqpollutants/nutrients/incentives.html|website=cals.ncsu.edu|access-date=3 July 2014|url-status=dead|archive-url=https://web.archive.org/web/20150923200107/http://www.cals.ncsu.edu/wq/wqp/wqpollutants/nutrients/incentives.html|archive-date=23 September 2015}}</ref><ref>{{cite web|last1=State-EPA Nutrient Innovations Task Group|title=An Urgent Call to Action – Report of the State-EPA Nutrient Innovations Task Group|url=https://www.epa.gov/sites/production/files/documents/nitgreport.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.epa.gov/sites/production/files/documents/nitgreport.pdf |archive-date=2022-10-09 |url-status=live|website=epa.gov|access-date=3 July 2014|date=2009}}</ref> In cases where eutrophication can be reversed, it may nevertheless take decades<ref>{{Cite web |title=Study shows eutrophic lakes may not recover for a millennium |url=https://news.wisc.edu/study-shows-eutrophic-lakes-may-not-recover-for-a-millennium/ |access-date=2022-11-03 |website=news.wisc.edu|date=13 June 2005 }}</ref> and significant soil management<ref>{{Citation |last=Wilkinson |first=Grace M. |title=Eutrophication of Freshwater and Coastal Ecosystems |date=2017-01-01 |url=https://www.sciencedirect.com/science/article/pii/B9780124095489101605 |encyclopedia=Encyclopedia of Sustainable Technologies |pages=145–152 |editor-last=Abraham |editor-first=Martin A. |place=Oxford |publisher=Elsevier |language=en |doi=10.1016/b978-0-12-409548-9.10160-5 |isbn=978-0-12-804792-7 |access-date=2022-11-03}}</ref> before the accumulated nitrates in [[groundwater]] can be broken down by natural processes.

====Nitrate pollution====
Only a fraction of the nitrogen-based fertilizers is converted to plant matter. The remainder accumulates in the soil or is lost as run-off.<ref name=Nasir>{{cite book|doi=10.1007/978-94-007-7814-6_5 | pages=55–71| year=2014 | last1=Callisto | first1=Marcos | last2=Molozzi | first2=Joseline | last3=Barbosa | first3=José Lucena Etham | title=Eutrophication: Causes, Consequences and Control | chapter=Eutrophication of Lakes | isbn=978-94-007-7813-9 }}</ref> High application rates of nitrogen-containing fertilizers combined with the high [[water solubility]] of nitrate leads to increased [[Surface runoff#Agricultural issues|runoff]] into [[surface water]] as well as [[Leaching (agriculture)|leaching]] into groundwater, thereby causing [[groundwater pollution]].<ref>{{cite web |author1=C. J. Rosen |author2=B. P. Horgan |url=https://www.extension.umn.edu/garden/yard-garden/lawns/preventing-pollution-problems/ |title=Preventing Pollution Problems from Lawn and Garden Fertilizers |publisher=Extension.umn.edu |date=9 January 2009 |access-date=25 August 2010 |archive-url=https://web.archive.org/web/20140310024038/http://www.extension.umn.edu/garden/yard-garden/lawns/preventing-pollution-problems/ |archive-date=10 March 2014 |url-status=dead }}</ref><ref>{{cite journal |title=Fertilizer-N use efficiency and nitrate pollution of groundwater in developing countries |journal=Journal of Contaminant Hydrology |doi=10.1016/0169-7722(95)00067-4 |volume=20 |issue=3–4 |pages=167–184|bibcode=1995JCHyd..20..167S|year=1995 |last1=Bijay-Singh |last2=Yadvinder-Singh |last3=Sekhon |first3=G.S. }}</ref><ref>{{cite web |url=http://www.nofa.org/tnf/nitrogen.php |title=NOFA Interstate Council: The Natural Farmer. Ecologically Sound Nitrogen Management. Mark Schonbeck |publisher=Nofa.org |date=25 February 2004 |access-date=25 August 2010 |url-status=dead |archive-url=https://web.archive.org/web/20040324090920/http://www.nofa.org/tnf/nitrogen.php |archive-date=24 March 2004 }}</ref> The excessive use of nitrogen-containing fertilizers (be they synthetic or natural) is particularly damaging, as much of the nitrogen that is not taken up by plants is transformed into nitrate which is easily leached.<ref>{{cite journal | year = 2008| title = Roots, Nitrogen Transformations, and Ecosystem Services | journal = Annual Review of Plant Biology | volume = 59 | pages = 341–363 | doi=10.1146/annurev.arplant.59.032607.092932| pmid = 18444903 | last1 = Jackson | first1 = Louise E. | last2 = Burger | first2 = Martin | last3 = Cavagnaro | first3 = Timothy R. | issue = 1 | bibcode = 2008AnRPB..59..341J }}</ref>

Nitrate levels above 10&nbsp;mg/L (10 ppm) in groundwater can cause '[[blue baby syndrome]]' (acquired [[methemoglobinemia]]).<ref>{{cite journal |pmc=1638204 |title = Blue Babies and Nitrate-Contaminated Well Water | pmid=10903623 | volume=108 |issue = 7 |year=2000 |journal=Environ. Health Perspect. |pages=675–8 | last1 = Knobeloch | first1 = L | last2 = Salna | first2 = B | last3 = Hogan | first3 = A | last4 = Postle | first4 = J | last5 = Anderson | first5 = H | doi=10.1289/ehp.00108675|bibcode = 2000EnvHP.108..675K }}</ref> The nutrients, especially nitrates, in fertilizers can cause problems for natural habitats and for human health if they are washed off soil into watercourses or leached through soil into groundwater.<ref>[https://www.usgs.gov/special-topics/water-science-school/science/nitrogen-and-water Nitrogen and Water]</ref> Run-off can lead to fertilizing blooms of algae that use up all the oxygen and leave huge "dead zones" behind where other fish and aquatic life can not live.<ref>{{Cite web |last=Biello |first=David |language= en |date = March 14, 2008|title= Fertilizer Runoff Overwhelms Streams and Rivers--Creating Vast "Dead Zones" |url=https://www.scientificamerican.com/article/fertilizer-runoff-overwhelms-streams/ |access-date= |website= Scientific American}}</ref>