The government's ambitious farm modernization program has been imposed on tradition-bound peasants averse to rapid change. A large part of the land improvement and irrigation work has been accomplished through mass mobilization of peasants and of the urban population for so-called voluntary work on the model of the Chinese coolie system. Socialization of the land has had a deleterious effect on work incentives, with a consequent lag in the planned growth of agricultural production. Measures adopted by the government to ensure better work performance on the collective farms did not prove sufficiently effective, and a scaling down of the five-year plan target for agricultural production could therefore not be avoided. To provide the additional acreage needed for crop expansion, large-scale programs of land reclamation and melioration have been executed. At the same time, heavy stress has been laid on the improvement of farm techniques and on mechanization as means for increasing yields and production. A planned expansion of livestock herds and of the output of livestock products has been hampered by inadequate incentives for peasants and by a shortage of fodder. The agricultural potential is limited by the predominance of rugged mountain terrain and by frequent spring droughts that cause extensive damage to crops. To minimize the adverse effects of the droughts, an extensive irrigation system is being developed. In 1967 the area of land in agricultural use, excluding forests, roads, and homesites, amounted to about 3.0 million acres, or 43 percent of the country's total area. More than half of the agricultural land was in unimproved natural pastures, with an additional small acreage in natural meadows. Cultivated land bearing field and tree crops totaled about 1.4 million acres, of which about 1.1 million acres were arable land, equivalent to about two-thirds of an acre per capita. Almost half of the cultivated land was located in hilly and mountainous zones, which are less productive than the coastal plains. The agricultural acreage was expanded by 3 percent between 1950 and 1967, but a significant further expansion is precluded by the country's rugged terrain.