U.S. and global trade are greatly affected by the growth and stability of world markets, including changes in world population, economic growth, and income. Other factors affecting agricultural trade are global supplies and prices, changes in exchange rates, government support for agriculture, and trade protection policies.

With the productivity of U.S. agriculture growing faster than domestic food and fiber demand, U.S. farmers and agricultural firms rely heavily on export markets to sustain prices and revenues. Historically, U.S. imports have increased steadily, as demand for diversification in food expands. U.S. consumers benefit from imports because imports expand food variety, stabilize year-round supplies of fresh fruits and vegetables, and temper increases in food prices.

U.S. agricultural exports have been larger than U.S. agricultural imports since 1960, generating a surplus in U.S. agricultural trade. This surplus helps counter the persistent deficit in nonagricultural U.S. merchandise trade (see data on U.S. trade-agricultural trade ). Even if there were a trade deficit in agricultural products, this does not imply a lack of competitiveness on the part of U.S. agriculture. Rather, it reflects increasing diversity in consumers' food choices and changing relative exchange rates, which make U.S. goods relatively more/less expensive in international markets and import goods relatively less/more expensive.

ERS provides research and analysis on factors influencing U.S. agricultural exports and imports.