Introduction: Agriculture has changed dramatically, especially since the end of World War II. Food and fibre productivity rose due to new technologies, mechanization, increased chemical use, specialization and government policies that favoured maximizing production. These changes allowed fewer farmers with reduced labour demands to produce the majority of the food and fibre.
Humans, like all other species, exploit their surroundings for the resources they need to survive. Our current exploitation of the world, however, is greater than those of most species. There are many reasons for this exploitation but we will focus on one and that is our technology, which is used for various purposes. Like a few other species, we use tools, but the hand-held tools that we originally used could only adjust extremely local conditions. Today we are able to shape entire regions and our technology has progressed to the point where we can level mountains and control the flow of rivers, something that was simply impossible a relatively short while ago. We can now modify our world relatively easily and quickly.
Agriculture is the major farming activity. Agriculture's scale means not only that large area is directly affected, but that local and even regional climates can be affected. The draining of water from rivers and watersheds for irrigation leads to drier natural habitats. Those rivers that receive runoff from farmland are often poisoned by excessive nutrients and pesticides.
As agriculture has become more intensive, farmers have become capable of producing higher yields using less labour and less land. Growth of the agriculture has not, however, been an unmixed blessing. It, like every other thing, has its pros and cons. Topsoil depletion, groundwater contamination, the decline of family farms, continued neglect of the living and working conditions for farm labourers, increasing costs of production, and the disintegration of economic