This article examines the dynamics of agricultural systems used by small farmers in the northeast of the State of Pará (Brazil). Its goal is to relate specific forms of shifting cultivation and extractive industry in Amazonia with endogenous processes of economic decision making. It has resonated on the system dynamics, and public policies, which as of the 70’s have focused on agricultural modernization and creation of permanent crops, thus contributing to the achievement of agro-ecologic and agro-economic barriers. Based on the new dynamics, small family enterprises in Amazonia have to cope with public and private actions, which undermine their stability.
