Green Revolution

The Green Revolution began in the 1940s when the Rockefeller Foundation launched a research project to help improve agricultural yields in Mexico. Plant breeder Norman Borlaug (who won a Nobel Prize for his work) led the effort to develop a high-yield dwarf wheat crop that was resistant to pests and diseases and could yield more grain than traditional varieties.
By the 1960s, concern grew over potential famine in Southeast Asia, particularly India and Pakistan. Hunger and malnutrition was also a significant problem in both Asia and Latin America, a situation that was exacerbated by drought conditions. An outgrowth of the original Green Revolution was a joint effort by developed nations to help millions of people in India and other countries by developing hybrid seeds, fertilizers, and pesticides. In addition to high-yield wheat, other major food crop varieties, including semi-dwarf rice plants, sorghum, millet, maize, cassava, and beans, were developed to be pest resistant and grow quickly year round so farmers could use land more intensively.
According to the International Food Policy Research Institute, yields of both wheat and rice doubled in the countries where the high-yield varieties were introduced. However, not all countries have benefited. High-yield varieties depend on irrigation and the application of fertilizers and pesticides. In arid areas, such as sub-Saharan Africa, they were less successful as many farmers did not have access to fertilizers and pesticides. The Consultative Group on International Agricultural Research and other institutions are working to develop new breeds of food crops that are better suited to dry land farming.
High-yield farming methods have been criticized for their environmental impacts; a heavy reliance on fertilizers and pesticides, if improperly managed, can have significant effects on rivers and streams. Irrigation can also deplete groundwater supplies and contribute to salinization of soil. On the other hand, increasing yields reduces the amount of land needed for agriculture, permitting more land to remain intact or be utilized for an alternative purpose. Despite many issues, the evidence is substantial that green revolution farming methods have considerably improved agricultural productivity in many parts of the world.

Recommended Resources

Consultative Group on International Agriculture Research (CGIAR) 
CGIAR is an association, sponsored by the World Bank, FAO, and the United Nations Development Programme, that supports international agricultural research. Their site includes wide ranging publications on research efforts.
Agriculture and World Development 
This World Bank site provides articles and case studies on innovations in sustainable agriculture, including zero tilling.