Despite the fact that by 1980 Brazil's external debt approached US$100 billion and the effects of economic crisis were strongly felt, the government attempted to continue with previously launched integrated regional development projects including the "Polonoroeste" program. 3 phases were foreseen for the project, in Rondonia, Mato Grosso, and in new colonization zones. The goals of the Rondonia and Mato Grosso phases were to establish agriculture in the Amazon basin zone covered by the Polonoroeste, where the soils were reported to be of good or average quality although extremely heterogeneous over small areas. To avoid danger of rapid and complete deforestation, each colonist was to receive 100 hectares, 5 of which would be cleared and planted each year, allowing the forest to regenerate over 20 years. Colonists were expected to preserve 50 hectares of forest in their 100 hectare lots, but with increasing numbers of colonists the tendency has been to cut back the forest. Colonists were to receive credits and low interest loans repayable beginning 5 years after settlement over a period of 15 years. Since loans were not indexed, the amounts due would be a very small proportion of their initial worth in Brazil's inflationary economy. Boundary disputes sometimes resulting in armed conflict or murder have occurred in both Rondonia and especially in Mato Grosso between legal settlers and squatters, and between different categories of settlers. More serious has been the settlers' resentment and contesting of the large reserves set aside for the indigenous population, which has declined precipitously in recent years, probably as the result of massacres. In Mato Grosso, inequality in land holdings is demonstrated by the control over 55% of the land exercised by 1% of landholders. The demographic response to the colonization schemes was overwhelming. The populations of Rondonia and Mato Grosso respectively were estimated at 36,935 and 522,044 in 1950, 69,792 and 889,539 in 1960, 111,064 and 1,597,090 in 1970, and 490,153 and 2,506,063 in 1980. Since 1980, the rate of population growth has been 8%/year in Mato Grosso and over 16% in Rondonia, due primarily to immigration. Estimates of the rate of abandonment range from 10%-30%, with ill heath the main reason for departing. Malaria is rampant, especially in Rondonia, and other diseases also take their toll, while health services are inadequate. The extreme poverty of many settlers, exacerbated by economic problems, difficulty of clearing the forest and transporting goods, hard work, psychological and social difficulties brought on by isolation and loneliness and the lack of conveniences, and feelings of insecurity due to frequent clashes with Indians may be other reasons for leaving. It is too early for a definitive assessment of the successes and failures of the Polonoroeste project, but it is at least clear that Amazon settlement cannot be a permanent solution for Brazil's rapid population growth and related problems.