The 'territory' concept is addressed at a scale rarely envisaged—that of the plot —through the study of a large rice irrigation perimeter in the heart of the Lake Alaotra region in Madagascar. The methodology fol-lowed in this study relies on the processing of landholding inventories. These inventories are remarquable, first for their quality, as they are at the same time quantitative and mapped (GIS-based inventories). They also allow long-term trend analyses inasmuch as they take place for a long period of time, from 1970 to 2012. Results of this study consist in two different conclusions: first, an obvious trend for the fragmen-tation (division) of plots and the decrease in the size of holdings is identified, though this fragmentation is not equal everywhere. These results confirm the general trend observed in lake Alaotra region and in Madagascar regarding land pressure and fragmentation due to demographic and other socio-cultural fac-tors. Second, fragmentation dynamics hides other less perceptible landholding phenomena. Specifically, it masks land grabbing by new and enterprising rice growers who increase their holdings by profiting from the problems experienced by the smallest farm owners whose fragmented land is no longer viable.