About 90% of the population depends on agriculture for a living. Most agriculture consists of subsistence farming, with only about 15% of the total production marketed. An estimated 1,100,000 hectares (2,718,000 acres), or about 43% of the total land area, is arable or under permanent crops; about 74,000 hectares (182,800 acres) are irrigated. The average farm family plot is 0.8 hectares (two acres). Agriculture accounted for 50% of the GDP in 2001. Coffee and tea exports comprise the majority of foreign earnings; coffee alone accounted for 54% of exports of goods in 2001. Principal crops for local consumption are manioc, beans, bananas, sweet potatoes, corn, and sorghum. Production in 1999 included bananas, 1,511,000 tons, mostly for wine; manioc, 617,000 tons; sweet potatoes, 734,000 tons; beans, 227,000 tons; sorghum, 60,000 tons; corn, 129,000 tons; peanuts, 10,000 tons; and potatoes, 24,000 tons.
The primary export crop is coffee, chiefly of the arabica variety. The government regulates the grading, pricing, and marketing of the coffee crop, and all coffee export contracts require approval. In 2001/2002, coffee production was 13,020 tons. Other export crops are cotton and tea. Seed cotton production was 3,000 tons, and cotton fiber production (after ginning) was about 1,000 tons in 1999. That year, tea production was 7,000 tons. Tea exports in 2001 of 8,706 tons represented 17% of total exports (up from only 4% during the 1980s); the government has been encouraging cotton and tea production in order to diversify exports. Palm oil is obtained from trees in plantations along the shore of Lake Tanganyika. Tobacco and wheat cultivated in the highland areas also yield some cash income.
Much of the land has suffered a loss of fertility because of soil erosion from poor agricultural practices, irregularity of rainfall, lack of fertilizer, and shortened fallow periods.