BBC Nature: http://www.bbc.co.uk/nature/humanplanetexplorer/survival_skills/agriculture
ThinkQuest.org: http://library.thinkquest.org/TQ0312380/crop.htm
BBC Bitesize – Intensive Farming: http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway_pre_2011/greenworld/farmingrev1.shtml
National Geographic – Crops: http://education.nationalgeographic.com/education/encyclopedia/crop/?ar_a=1
Young People’s Trust for the Environment (YPTE) – GM Crops: http://www.ypte.org.uk/environmental/genetically-modified-foods/6
Page under development – more links shortly (24th February 2014)