Farming has been revolutionized in the past hundred years. In the 1890s, wheat was sown by hand, weeded by the hoe and harvested with the sickle and scythe, and about a third of the population were employed in some activity related to the growing of food. In 1945, 1 million people worked in farming in the UK, but by 1960, regular farm jobs had fallen to half a million; in 1994, the number had declined further to only 120,000 people. The largest single factor contributing to this change has been mechanization, in particular the replacement of the horse by the tractor. Harry Ferguson's prototype tractor arrived in 1933; by the mid-1950s, tractors outnumbered horses in the UK and now there are about half a million of them. The power of the tractor has increased greatly from Ferguson's prototype: it is estimated that modern farming requires the equivalent of 25 million horses.

One of the consequences of this mechanization is the change in the size of the fields. If a farmer is working in a 2-hectare field with a 3-metre wide implement behind the tractor, one-third of the time is spent cultivating the ground whilst two-thirds is spent turning the machine around, going round the edges or going to another field. If the field is 40 hectares, however, two-thirds of the time is spent cultivating. For this reason, fields have been enlarged to accommodate the bigger machines and to increase productivity. The bigger fields are created by removing the hedges and fences. In the period between 1978 and 1984, 28,000 km of hedges were removed by farmers and only 3,500 km of new ones planted.