E. Böserup’s (1965) view that increases in population size stimulate agricultural change. ‘Pre-industrial farmers, according to the Boserup model, were almost always technically capable of increasing the productivity of their land by applying methods (soil tillage, additional weeding, application of organic fertilisers and irrigation) which allowed it to be cropped more frequently and fallowed for shorter periods. But because such methods typically demanded higher labour inputs per unit of production, they tended to be adopted only when population pressure and the resulting land scarcity forced farmers to work harder in order to maintain existing levels of subsistence’ (Henley (2005) Asia Pac. Viewpt 46, 2). Brookfield (2001) Asia Pac. Viewpt 42 has doubts, observing that agricultural intensification has more often been inspired by price incentives to surplus production, rather than though population pressure.