From Geertz's ecological viewpoint, the essential difference between the two lies in how each system responds to a rising population. The response of the swidden system to population growth is dispersive and inelastic, absorbing additional people by outwardly enlarging the area under cultivation, while that of the sawah system is concentrative and inflatable, absorbing more people by intensifying cultivation on a fixed land base. Crucial to the latter is the improvement of the supply and control of water There is a special kind of dynamic at work here, such that improvements in cultivation methods allow more labor to be employed per unit of land, leading to an increase in production[11, pp. 28-371.