 Mechanisation of arable farming started during the First World War, in an attempt to increase efficiency due to the scarcity of labour, and continued during the depression of the interwar period, when low food prices sharply reduced farmers' profits.It accelerated with the outbreak of the Second World War, and continued since then.A total of of pasture were ploughed during the Second World War to increase the production of wheat, potatoes and root vegetables, with the Women's Land Army, school children, refugees and prisoners of war all contributing labour.