## Abstract

This article questions the processes of agro-ecological adaptation and the mobility of peasant communities in the face of hydro-morphological hazards and land constraints imposed by the State in the Brahmaputra alluvial plain in Assam (India). Indeed, the states which successively ruled the alluvial plain of the Brahmaputra (Ahom kingdom, British, independent India) have built dikes in order to control the river and ensure the intensification of rice production. However, these developments are disrupting river dynamics. Farmers are adapting their agricultural practices, notably by developing different types of rice crops. However, they also have to deal with flooding following unforeseen dike failures. Their land disappears eroded by the river or buried under sand deposits. As a result, they relocate their villages to dykes, alluvial ridges and appropriate agricultural land often without rights or titles. The land constraints imposed by the state limit these practices and the mobility of young people to urban spaces appears as a new alternative for the rural communities of this densely populated plain.