Editing Agriculture (section)

=== Crop cultivation systems ===
[[File:An example of slash and burn agriculture practice Thailand.jpg|thumb|left|[[Slash and burn]] shifting cultivation, Thailand]]

Cropping systems vary among farms depending on the available resources and constraints; geography and climate of the farm; government policy; economic, social and political pressures; and the philosophy and culture of the farmer.<ref name="FAO FS">{{cite web |publisher=Food and Agriculture Organization |url=http://www.fao.org/farmingsystems/description_en.htm |title=Analysis of farming systems |access-date=22 May 2013 |url-status=live |archive-url=https://web.archive.org/web/20130806063804/http://www.fao.org/farmingsystems/description_en.htm |archive-date=6 August 2013}}</ref><ref name="PCP APS">"Agricultural Production Systems". pp. 283–317 in [[#Acquaah|Acquaah]].</ref>

Shifting cultivation (or [[slash and burn]]) is a system in which forests are burnt, releasing nutrients to support cultivation of annual and then [[perennial plant|perennial]] crops for a period of several years.<ref name="CS">"Farming Systems: Development, Productivity, and Sustainability", pp. 25–57 in [[#Chrispeels|Chrispeels]]</ref> Then the plot is left [[fallow]] to regrow forest, and the farmer moves to a new plot, returning after many more years (10–20). This fallow period is shortened if population density grows, requiring the input of nutrients (fertilizer or [[manure]]) and some manual [[pest control]]. Annual cultivation is the next phase of intensity in which there is no fallow period. This requires even greater nutrient and pest control inputs.<ref name="CS" />

[[File:Intercropping coconut n Tagetes erecta.jpg|thumb|[[Intercropping]] of [[coconut]] and [[Tagetes erecta|Mexican marigold]]]]

Further industrialization led to the use of [[monoculture]]s, when one [[cultivar]] is planted on a large acreage. Because of the low [[biodiversity]], nutrient use is uniform and pests tend to build up, necessitating the greater use of [[pesticide]]s and fertilizers.<ref name="PCP APS" /> [[Multiple cropping]], in which several crops are grown sequentially in one year, and [[intercropping]], when several crops are grown at the same time, are other kinds of annual cropping systems known as [[polyculture]]s.<ref name="CS" />

In [[subtropics|subtropical]] and [[arid]] environments, the timing and extent of agriculture may be limited by rainfall, either not allowing multiple [[Annual plant|annual crops]] in a year, or requiring irrigation. In all of these environments perennial crops are grown (coffee, chocolate) and systems are practiced such as [[agroforestry]]. In [[Temperateness|temperate]] environments, where ecosystems were predominantly [[grassland]] or [[prairie]], highly productive annual farming is the dominant agricultural system.<ref name="CS" />

Important categories of food crops include cereals, legumes, forage, fruits and vegetables.<ref name="FAO" /> [[Natural fiber]]s include cotton, [[wool]], [[hemp]], silk and [[flax]].<ref>{{cite web |title=Profiles of 15 of the world's major plant and animal fibres |url=http://www.fao.org/natural-fibres-2009/about/15-natural-fibres/en/ |publisher=FAO |access-date=26 March 2018 |date=2009 |archive-date=3 December 2020 |archive-url=https://web.archive.org/web/20201203113011/http://www.fao.org/natural-fibres-2009/about/15-natural-fibres/en/ |url-status=live}}</ref> Specific crops are cultivated in distinct [[growing region]]s throughout the world. Production is listed in millions of metric tons, based on [[Food and Agriculture Organization|FAO]] estimates.<ref name="FAO" />
<div style=display:inline-table>
{|class="wikitable collapsible"
|-
! colspan=2|Top agricultural products, by crop types <br />(million tonnes) 2004 data
|-
|Cereals ||style="text-align:right;"|2,263
|-
|Vegetables and melons ||style="text-align:right;"|866
|-
|[[Root]]s and [[tuber]]s ||style="text-align:right;"|715
|-
|Milk ||style="text-align:right;"|619
|-
|Fruit ||style="text-align:right;"|503
|-
|Meat ||style="text-align:right;"|259
|-
|[[Vegetable oil|Oilcrops]] ||style="text-align:right;"|133
|-
|Fish (2001 estimate) ||style="text-align:right;"|130
|-
|[[Egg (food)|Eggs]] ||style="text-align:right;"|63
|-
|[[Pulse (legume)|Pulses]] ||style="text-align:right;"|60
|-
|[[Fiber crop|Vegetable fiber]] ||style="text-align:right;"|30
|-
|colspan=2|''Source: [[Food and Agriculture Organization]]''<ref name="FAO">{{cite web |url=http://faostat.fao.org/ |title=Food and Agriculture Organization of the United Nations (FAOSTAT) |access-date=2 February 2013 |archive-url=https://web.archive.org/web/20130118190636/http://faostat.fao.org/ |archive-date=18 January 2013}}</ref>
|}
</div>
<div style=display:inline-table>
{|class="wikitable collapsible"
|-
! colspan=2|Top agricultural products, by individual crops <br />(million tonnes) 2011 data
|-
|Sugar cane ||style="text-align:right;"|1794
|-
|Maize ||style="text-align:right;"|883
|-
|Rice ||style="text-align:right;"|722
|-
|Wheat ||style="text-align:right;"|704
|-
|Potatoes ||style="text-align:right;"|374
|-
|Sugar beet ||style="text-align:right;"|271
|-
|Soybeans ||style="text-align:right;"|260
|-
|Cassava ||style="text-align:right;"|252
|-
|Tomatoes ||style="text-align:right;"|159
|-
|Barley ||style="text-align:right;"|134
|-
|colspan=2|''Source: [[Food and Agriculture Organization]]''<ref name="FAO" />
|}
</div>