Since the mid-1990s extensive agriculture using irrigation has grown rapidly in Argentina. Where farming on dry land was traditionally carried out, technological change has created a new waterscape: "irrigated land." To understand the creation of this conceptual category and how it is anchored in a specific production model, in this paper I contextualize the spread of mechanized irrigation in the north of the province of Buenos Aires by examining the main public policies that intervene in this territorial transformation: the Competitive Improvement Plan of the Seed Cluster, the National Irrigation Plan, and the management of groundwater for productive irrigation. Integrating contributions from Political Ecology and Science and Technology Studies, I argue that the exploitation of groundwater for irrigation implies the privatization of a resource that remains invisible. "Irrigated land" contains two of the fundamental resources for food production that, jointly, resignify each other. Water acquires productive meaning as a commodity to which it is feasible to assign a monetary value, and becomes privatized de facto at the moment of its productive consumption; while the land - thanks to water - is valorized economically by allowing for new exploitation alternatives with higher profit margins. Thus, water acts as the "lubricant" that reinforces the accumulation process.