A distinctive feature of the country's labor scene is the practice of mobilizing large numbers of the population for so-called voluntary work on various types of construction and agricultural projects, including the building of railroads, housing, and irrigation canals; land improvement; harvesting; and the planting of trees. Thousands and, at times, tens of thousands of individuals from all walks of life, including members of the armed forces, are assembled by the government to carry out specific jobs with simple tools or with their bare hands. Party dogma holds that these projects, which use vast numbers of people, reflect the Party's strength, the might of the masses, and the great reserves to be found in their midst. The projects are considered to be not only of great economic and social importance but also of great ideological, political, and educational significance because, among other things, they reflect the determination and readiness of the broad working masses to implement the Party's line. Official complaints about flagging enthusiasm for housing construction in 1968 suggest a less favorable public acceptance of this practice than that proclaimed by the Party dogma. AGRICULTURE Agriculture is organized on the Stalinist Soviet model: all activity is centrally planned, and farm operations are carried out by state and collective farms. Government policy has accorded a high priority to the expansion and modernization of agricultural production as a means of attaining self-sufficiency in foods. In an effort to obviate the historical dependence on grain imports, the government has placed special emphasis on increasing the output of bread grains, which furnish the bulk of the people's diet, and on a rapid rise in the production of potatoes as a substitute for bread. Great importance is attached to the expansion of industrial crops, such as cotton, tobacco, sugar beets, and sunflowers, in order to provide raw materials for the growing domestic industries, in addition to maintaining traditional exports. Expansion of grape vineyards, olive groves, and other fruit and vegetable growing has also been promoted to develop larger exportable surpluses. According to official data, farm output increased half again as fast as the population between 1950 and 1967, but it is still inadequate to supply the country's minimum needs for bread and livestock products.