Editing Fertilizer (section)

==== Acidification ====
Soil acidification refers to the process by which the pH level of soil becomes more acidic over time. Soil pH is a measure of the soil's acidity or alkalinity and is determined on a scale from 0 to 14, with [[Seven (1995 film)|7]] being neutral. A pH value below 7 indicates acidic soil, while a pH value above 7 indicates alkaline or basic soil.

Soil acidification is a significant concern in agriculture and horticulture. It refers to the process of the soil becoming more acidic over time. {{See also|Soil pH|Soil acidification}}
Nitrogen-containing fertilizers can cause [[soil acidification]] when added.<ref>{{cite journal|doi= 10.1126/science.324_721b |pmid = 19423798 |bibcode = 2009Sci...324..721S | volume=324 |issue = 5928 | title=Eutrophication: More Nitrogen Data Needed |journal=Science |pages=721–722|year = 2009 |last1 = Schindler |first1 = D. W. |last2 = Hecky |first2 = R. E. }}</ref><ref>{{cite journal|doi=10.2136/sssaj2007.0071N | volume=72 | issue=1 | title=Phosphorus Solubility in Response to Acidification of Dairy Manure Amended Soils | journal=Soil Science Society of America Journal | pages=238| bibcode=2008SSASJ..72..238P | year=2008 | last1=Penn | first1=C. J. | last2=Bryant | first2=R. B. }}</ref> This may lead to decrease in nutrient availability which may be offset by [[liming (soil)|liming]]. These fertilizers release ammonium or nitrate ions, which can acidify the soil as they undergo chemical reactions.

When these nitrogen-containing fertilizers are added to the soil, they increase the concentration of hydrogen ions (H+) in the soil solution, which lowers the pH of the soil.