Since the 1990s, ecological footprint (EF) analysis has been employed to discuss two important dimensions of sustainable development, intra- and inter-generational equity, from the perspective of ecosystem appropriation. When examining the equality of resource use among generations in the EF analysis, sustainable yield plays a crucial role; however, its value is assumed to be the same as that of average industrial yield, which does not reflect differential productivity and its value can be much higher than the sustainable one through over-exploitation practices. The estimated EF, as well as ecological deficits, would be underestimated, from which false policy implications could be drawn. Through a review of the literature on the relationships between yield, soil quality, and fanning practices, this paper suggests adopting a yield potential ranking system that was established by the government in Taiwan in 1991 through an 8-year field study. This ranking system served as a proxy for local sustainable yield in estimating the required paddy fields in Taiwan in 1996 under two scenarios. Scenario (1) concerned the required paddy fields for supporting the direct and indirect consumption of rice by Taiwan residents; Scenario (11) explored the additional area of paddy fields that would be needed when the food energy from cereals is provided exclusively by rice and the importing of rice is not possible. The results were then compared with the estimates when the average industrial yield of 1996 was used. A hybrid-units input-output modeling method was used to estimate the rice contained in manufactured products. The results of the scenario analysis shed light on the importance of preserving Taiwan's existing paddy fields for the sake of maintaining stable long-term food supply. (c) 2005 Elsevier B.V. All rights reserved.
