It is also clear that further gains in production are still to come, thanks both to expansion of the agricultural frontier and higher yields.

Cochrane et al.(1985) describe these two regions as; 'undoubtedly the most rapidly expanding agricultural frontiers in the Americas'.

The agricultural frontier in the Amazon is pushed along by a multi-billion dollar per year economy.

However, the expansion of the agricultural frontier is a perennial threat to the natural bounty of the department.

But in the 1950's Brazil's agricultural frontier was marching across Parana.

The Chaco is one of South America's last agricultural frontiers.

Some Minnesota farmers regard such statements from the state's most powerful company and the expansion of Brazil's agricultural frontier as a very bad omen.

Already swollen by the great wave of migrants on this agricultural frontier, Porto Velho's population has doubled to 320,000 in just four years.

In this way, they believe, the agricultural frontier advanced.

Overpopulation, open agricultural frontiers, and rising industrial centers attracted voluntary migrants.