Check out my introduction to this new Real Food Series and Part 1 if you haven't already.
By the middle of the 20th century farming was transforming in ways it never had. Private family farms were quickly diminishing and being replaced with large, corporate, mono-cultural farms. As farms continued to increase in size farmers were eliminating hay and meadows from the planting rotation cycle that had been used in the past. Animals where no longer used as a part of the farming process and instead were separated out and put on to farms of their own. Chemical fertilizers were also becoming widely available and understandably so because they allowed farmers to increase their crop yield and better meet the demand for inexpensive food.
1950's - 1990's
By the middle of the 20th century farming was transforming in ways it never had. Private family farms were quickly diminishing and being replaced with large, corporate, mono-cultural farms. As farms continued to increase in size farmers were eliminating hay and meadows from the planting rotation cycle that had been used in the past. Animals where no longer used as a part of the farming process and instead were separated out and put on to farms of their own. Chemical fertilizers were also becoming widely available and understandably so because they allowed farmers to increase their crop yield and better meet the demand for inexpensive food.
The use of supplemental nutrients to increase crop yield started as trial and error in the form of wood ashes, ground bones, salt peter, and gypsum. Justus von Liebig (1803–1873), a German chemist, laid the foundation for the use of chemical fertilizers as a source of plant nutrients starting in 1840. He recognized the importance of various mineral elements derived from the soil in plant nutrition and the necessity of replacing those elements in order to maintain soil fertility. Two British scientists, J.B. Lawes and J.H. Gilbert, in turn established the agricultural experiment station at Rothamsted, in the United Kingdom. They built on the work of Liebig and experimentally demonstrated the importance of chemical fertilizers in improving and maintaining soil fertility. In fact, the application of synthetic fertilizers was the basis of the global increase in agricultural production after World War II.
~Pollution Issues: Agriculture