Editing Agriculture (section)

=== Energy dependence ===
[[File:Baumwoll-Erntemaschine auf Feld.jpeg|thumb|left|[[Mechanised agriculture|Mechanized agriculture]]: from the first models in the 1940s, tools like a [[cotton picker]] could replace 50 farm workers, at the price of increased use of [[fossil fuel]].]]

Since the 1940s, agricultural productivity has increased dramatically, due largely to the increased use of energy-intensive mechanization, fertilizers and pesticides. The vast majority of this energy input comes from [[fossil fuel]] sources.<ref>{{cite news |url=https://www.independent.co.uk/news/science/world-oil-supplies-are-set-to-run-out-faster-than-expected-warn-scientists-453068.html |title=World oil supplies are set to run out faster than expected, warn scientists |archive-url=https://web.archive.org/web/20101021233714/http://www.independent.co.uk/news/science/world-oil-supplies-are-set-to-run-out-faster-than-expected-warn-scientists-453068.html |archive-date=21 October 2010 |work=[[The Independent]] |date=14 June 2007 |access-date=14 July 2016}}</ref> Between the 1960s and the 1980s, the Green Revolution transformed agriculture around the globe, with world grain production increasing significantly (between 70% and 390% for wheat and 60% to 150% for rice, depending on geographic area)<ref>{{cite web |title=The Future of the Green Revolution: Implications for International Grain Markets |last=Herdt |first=Robert W. |url=http://www.rockefellerfoundation.org/uploads/files/06132caf-3d72-49e4-817d-ae89e0249d18.pdf |publisher=The Rockefeller Foundation |date=30 May 1997 |access-date=16 April 2013 |page=2 |url-status=live |archive-url=https://web.archive.org/web/20121019153636/http://www.rockefellerfoundation.org/uploads/files/06132caf-3d72-49e4-817d-ae89e0249d18.pdf |archive-date=19 October 2012}}</ref> as [[world population]] doubled. Heavy reliance on [[petrochemical]]s has raised concerns that oil shortages could increase costs and reduce agricultural output.<ref name="ncseonline.org" />

Industrialized agriculture depends on [[fossil fuels]] in two fundamental ways: direct consumption on the farm and manufacture of inputs used on the farm. Direct consumption includes the use of lubricants and fuels to operate farm vehicles and machinery.<ref name="ncseonline.org">{{cite web |last=Schnepf |first=Randy |date=19 November 2004 |title=Energy use in Agriculture: Background and Issues |website=CRS Report for Congress |url=http://www.nationalaglawcenter.org/wp-content/uploads/assets/crs/RL32677.pdf |publisher=[[Congressional Research Service]] |access-date=26 September 2013 |url-status=live |archive-url=https://web.archive.org/web/20130927190908/http://www.nationalaglawcenter.org/wp-content/uploads/assets/crs/RL32677.pdf |archive-date=27 September 2013}}</ref>

Indirect consumption includes the manufacture of fertilizers, pesticides, and farm machinery.<ref name="ncseonline.org" /> In particular, the production of [[nitrogen fertilizer]] can account for over half of agricultural energy usage.<ref>{{cite journal |title=Energy and the food system |last1=Woods |first1=Jeremy |last2=Williams |first2=Adrian |last3=Hughes |first3=John K. |last4=Black |first4=Mairi |last5=Murphy |first5=Richard |date=August 2010 |doi=10.1098/rstb.2010.0172 |pmid=20713398 |pmc=2935130 |journal=[[Philosophical Transactions of the Royal Society]] |volume=365 |pages=2991–3006 |issue=1554 |doi-access=free}}</ref> Together, direct and indirect consumption by US farms accounts for about 2% of the nation's energy use. Direct and indirect energy consumption by U.S. farms peaked in 1979, and has since gradually declined.<ref name="ncseonline.org" /> [[Food systems]] encompass not just agriculture but off-farm processing, packaging, transporting, marketing, consumption, and disposal of food and food-related items. Agriculture accounts for less than one-fifth of food system energy use in the US.<ref name="ers.usda.gov">{{cite web |author1=Canning, Patrick |author2=Charles, Ainsley |author3=Huang, Sonya |author4=Polenske, Karen R. |author5=Waters, Arnold |year=2010 |title=Energy Use in the U.S. Food System |website=USDA Economic Research Service Report No. ERR-94 |publisher=United States Department of Agriculture |url=http://www.ers.usda.gov/Publications/ERR94/ |url-status=dead |archive-url=https://web.archive.org/web/20100918182458/http://www.ers.usda.gov/publications/err94/ |archive-date=18 September 2010}}</ref><ref name="css.snre.umich.edu">{{cite web |last1=Heller |first1=Martin |last2=Keoleian |first2=Gregory |year=2000 |title=Life Cycle-Based Sustainability Indicators for Assessment of the U.S. Food System |publisher=University of Michigan Center for Sustainable Food Systems |url=http://css.snre.umich.edu/css_doc/CSS00-04.pdf |access-date=17 March 2016 |url-status=dead |archive-url=https://web.archive.org/web/20160314094203/http://css.snre.umich.edu/css_doc/CSS00-04.pdf |archive-date=14 March 2016}}</ref>