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Use of primitive agricultural techniques was the historical standard. The vast majority of the world population engaged in subsistence agriculture and yields remained low. Between the 16th century and the mid-19th century, Great Britain saw a massive increase in agricultural productivity and net output. New agricultural practices like enclosure, mechanization, four-field crop rotation and selective breeding enabled an unprecedented population growth, freeing up a significant percentage of the workforce, and thereby helped drive the Industrial Revolution. By the early 19th century, agricultural practices, particularly careful selection of hardy strains and cultivars, had so improved that yield per land unit was many times that seen in the Middle Ages and before. It is estimated that the productivity of wheat went up from about 19 bushels per acre in 1720 to 21–22 bushels by the middle of the century and finally stabilised at around 30 bushels by 1840.[76] The Agricultural Revolution was a major turning point in history. The population of England in 1750 reached the level of 5.7 million, just as it had done in the past in around 1350 and again in 1650. This time, instead of a Malthusian catastrophe occurring from plague or famine, the population growth remained sustained. One of the keys to the British Agricultural Revolution was the development of ways of keeping and improving the arable land in Great Britain to counteract the loss of the soil's plant nutrients in cropping a given area. Higher yielding land was added to higher yielding crops with more yield/acre. Farm workers using more productive tools and machinery produced more crops with fewer workers. The Agricultural Revolution picked up speed as the Industrial Revolution and the advances in chemistry produced the scientific knowledge, wealth and technology for a more systematic development of commercial fertilizers and new and more productive agricultural machinery. Advice on more productive techniques for farming began to appear in England in the mid-17th century, from writers such as Samuel Hartlib, Walter Blith and others.[77] The main problem in sustaining agriculture in one place for a long time was the depletion of nutrients, most importantly nitrogen levels, in the soil. To allow the soil to regenerate, productive land was often let fallow and in some places crop rotation was used. A four-field rotation was popularised by the British agriculturist Charles Townshend in the 18th century. The system (wheat, turnips, barley and clover), opened up a fodder crop and grazing crop allowing livestock to be bred year-round. The use of turnip was especially important as the legume roots were an important source of nutrients for the soil. Another catalyst for improvement came from the Enclosure movement. Prior to the 18th century, agriculture across Europe used the feudal open field system with subsistence farmers cropping strips of land in fields held in common and splitting up the produce; this was very inefficient and reduced incentive to improve the productivity. Many farms began to be enclosed by Yeomen who improved the use of their land. This process accelerated in the 15th and 16th centuries with special acts of Parliament to expedite the legal process. This culminated in the General Enclosure Act of 1801, which sanctioned large-scale land reform. The mechanisation and rationalisation of agriculture was another important factor. Robert Bakewell and Thomas Coke introduced selective breeding, and initiated a process of inbreeding to maximise desirable traits from the mid 18th century, such as the New Leicester sheep. Machines were invented to improve the efficiency of various agricultural operation, such as Jethro Tull's seed drill of 1701 that mechanised seeding at the correct depth and spacing and Andrew Meikle's threshing machine of 1784. Ploughs were steadily improved, from Joseph Foljambe's Rotherham iron plough in 1730[78] to James Small's improved "Scots Plough" metal in 1763. In 1789 Ransomes, Sims & Jefferies was producing 86 plough models for different soils.[79] Traction machines also began to replace horsepower on the farms in the 19th century. The scientific investigation of fertilization began at the Rothamsted Experimental Station in 1843 by John Bennet Lawes. He investigated the impact of inorganic and organic fertilizers on crop yield and founded one of the first artificial fertilizer manufacturing factories in 1842. Fertilizer, in the shape of sodium nitrate deposits in Chile, was imported to Britain by John Thomas North as well as guano (birds droppings). The first commercial process for fertilizer production was the obtaining of phosphate from the dissolution of coprolites in sulphuric acid.[80] The repeal of the Corn Laws in 1846 that removed tariffs on food imports, and the development of steamships and railways, which revolutionised the transportation of food, allowed a truly global market for food to emerge. This reduced volatility in food prices as scarcity in one area could be offset by cheap imports from another area. The work of Charles Darwin and Gregor Mendel created the scientific foundation for plant breeding that led to its explosive impact over the past 150 years.[81] Firms, such as Gartons Agricultural Plant Breeders began to market hybrid crops in the 1890s. |
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