First Agricultural Revolution- Also known as the Neolithic Revolution was when human beings first domesticated plants and animals and no longer relied entirely on hunting and gathering. By growing plants and raising animals, human beings created larger and more stable sources of food, so more people could survive. Areas still remained in stage one of the demographic transition with the first agricultural revolution. The First Agricultural Revolution came about 10,000 years ago in Melanesia and around 2,500 BC in Subsaharan Africa. Geographer Carl Sauer, however, believes that plant domestication began in Southeast and South Asia more than 14,000 years ago with the planned cultivation of root crops-crops that are reproduced by cultivating either the roots or cuttings from the plants. A similar but later development may have taken place in northwestern South America. The First Agricultural Revolution changed the small, mobile groups of hunter-gatherers that were common into sedentary societies based in built-up villages and towns. These societies modified their natural environment by means of specialized cultivation and storage technologies (e.g. irrigation) that created surplus production. These changes were the beginnings of high population densities, complex labor diversification, trading economies, centralized administrations and political structures, ideologies and systems of knowledgelike writing. Note that seed agriculture is what really started widescale farming of this revolution.
The second agricultural revolution was the innovation, improvements and techniques developed in Great Britain and other neighboring countries between the 17th century and the end of the 19th century. This brought a massive increase in agricultural productivity and net output which in turn supported unprecedented population growth, freeing up a significant percentage of the workforce, and thereby helped drive the Industrial Revolution. The governments of Europe played a role in spurring on the Second Agricultural Revolution by passing laws such as the Enclosure Act of Great Britain that encouraged consolidation of fields into large, single-owner holdings. Farmers increased the size of their farms, fenced in their land, and started to rotate fields. Methods of soil fertilization, crop care and harvesting improved. New technologies improved production as well. These include: the seed drill that made planting in rows easier and advances in breeding livestock that made breeds better producers of food such as milk or beef. The Industrial Revolution helped sustain the second agricultural revolution through machines such as the railroad that helped build agriculture in the Great Plains of the United States as well as other machines such as the tractor and combine. By the 1830s, fertilizers and artificial feeds to livestock helped make it possible to feed larger urban populations which in turn led to the growth of an industrial economy. More efficient agriculture freed people to work in factories, producing other goods and generating enough food for the industrial workers.
Third Agricultural Revolution- also known as the Green Revolution involves two main practices: the introduction of new higher-yield seeds and the expanded use of fertilizers. The green revolution dates as far back as the 1930s, when agricultural scientists in the Midwest began manipulating seed varieties to increase crop yield. In the 1940s research on corn production in Mexico produced a hybrid seed that would grow better. By 1960 Mexico was no longer importing corn because production within the country was high enough to meet demand. Because of the green revolution, agricultural productivity at a global scale has increased faster than population growth. Today, most famines result from political instability rather than failure in production. India became self-sufficient in grain production by the 1980s, and Asia saw a 2/3 increase in rice production between 1970 and 1995. The geographical impact of the Green revolution is highly variable; as in Africa where it has had only a limited impact since agriculture is based on different crops and there is lower soil fertility. An entire field of biotechnology has sprung from the Third Agricultural Revolution and the development of genetically modified organisms, which is principally, genetically engineered crops.