Cambodia was a farming area in the first and second millennia BCE. States in the area engaged in trade in the Indian Ocean and exported rice surpluses. Complex irrigation systems were built in the 9th century. The French colonial period left the large feudal landholdings intact. Roads and a railway were built, and rubber, rice and corn grown. After independence Sihanouk pursued a policy of economic independence, securing aid and investment from a number of countries. Bombing during the Vietnam War damaged rice production. Lon Nol had a policy of liberalising the economy. This was followed by the victory of the Khmer Rouge and the emptying of the cities. After the defeat of the Khmer Rouge, a Five Year Plan was adopted, aiming to improve agriculture, industry and distribution, with a slogan of "export and thrift". Today, Cambodia remains a largely agricultural economy and industrial development is slow.
Wartime economy, 1970-75
The war that engulfed the rest of Indochina spread to Cambodia in April 1970, shortly after the coup that deposed Prince Sihanouk. Wartime conditions had a major impact on the country's economy, especially on the export sector. Production and export of virtually all commodities dropped sharply, as insecurity spread throughout the countryside. Intense combat in the nation's most densely populated farming areas caused a large segment of the peasant population to flee to cities and to towns. By 1975 the population of Phnom Penh had swollen to 2 million, from just 50,000 in 1955. Moreover, the war seriously dislocated the economic system. Food shortages arose as insurgents interrupted the transportation of crops from the countryside to the main marketing centers. Increasing budgetary expenditures, skyrocketing inflation, shrinking export earnings, and a rising balance-of-payments deficit plagued the war-torn economy.
The war's most damaging effect was on rice production. In 1972 Cambodia needed to import rice