agricultural subsidies:
According to the USDA's website, in the 1930s about 25% of the U.S. population lived and worked on the nation's six million small farms and these subsidies protected the livelihood of farmers --- at that time about a quarter of the country's population. However, by 1997 about 157,000 large farms accounted for 72% of farm sales, with only two percent of the U.S. population residing on farms.
(...) This changing of the American farming landscape without a significant change in agricultural subsidies policy has created a system that encourages overproduction of crops. Farmers (mostly large scale farmers, or corporate farmers) produce as much of a product as they can. Since they are guaranteed a minimum price by the U.S. government, whatever cost of production the market value of their crops do not cover, the government makes up the difference.
(...) All the extra crops are dumped onto the international market which drives the prices of those goods lower than the cost to grow them. This is simply devastating to the many countries who base their wellfare on agriculture. Take the cotton industry. According to Oxfam America, a non-profit organization dedicated to ending world poverty, more than ten million people in West and Central African countries earn their livelihoods from cotton production. Oxfam says, "The United States is the world's largest exporter and subsidizer of cotton, spending nearly four billion a year on subsidies ... this is roughly three times the entire U.S. aid budget for Africa's 500 million people." The resultant overproduction and dumping of cotton on the world market, drives the price of cotton below what it takes to produce, even in small countries where the cost of production is lower than in the U.S.
(...) Even within the United States, agricultural subsides clearly benefit large scale corporate farms and not small family owned farms. According to a press release from Oxfam, the largest ten percent of cotton farms receive three quarters of total payment. In 2001, ten farms received $17 million between them. And this kind of statistic holds true across other kinds of crops that the U.S. government also subsidizes.