Because agriculture is so important to a nation's well-being, governments have always been concerned with it. For example, the United States and Canada have long produced surpluses that complicate their economies. Surpluses tend to lower prices to farmers and seriously endanger the agriculture industry. Governments have instituted systems of price supports to maintain a fair price when surpluses cause prices to drop. The system in the United States is a good example. A government program supports the prices paid to farmers for grains, and other agricultural products. Support prices are based on parity, which is the ratio between the prices farmers receive for their crops and the prices they must pay for things they need. The government selected the period from 1910 to 1914 as a time when farm prices were in a fair ratio with farming costs. This is the base period now used to determine parity prices. The idea is to assure farmers that what they get for a bushel of wheat will buy the same amount of, say, seed as it did in the years of the base period; if prices drop too far below this ideal the government can help in a number of ways. For example, it may buy much of a surplus at parity prices. Governments have instituted a wide variety of other controls for prices and, also, for farm output, mainly at the request of the farmers themselves. Farm prices tend to fluctuate more than other prices do, and the incomes of farmers fluctuate along with farm prices. Various measures for maintaining farm prices and incomes include tariff or import levies, import quotas, export subsidies, direct payment to farmers, and limitations on production. All of these measures are useful and are used to some extent by most developed countries. An important example of such a program is the soil-bank plan, which aimed at limiting production while improving farmland. The European Economic Community (EEC) established a common agricultural policy (CAP) for its member nations, called the Common Market countries. The aim is to create free trade for individual commodities within the community. When production of a commodity exceeds EEC consumption, the EEC may buy the excess for storage, pay to have it reprocessed, or export it to countries outside the Common Market. In this way the EEC can maintain its members' farm prices at levels equal to or even higher than those in such market-competitive nations as the United States and Canada. By saying that a country's agricultural surpluses often 'complicate' its economy, the author means ______.