フィリピン公共灌漑投資の規定要因

グレンジャー因果性による検証

抄録

Using the time-series data on irrigation investments in the Philippines compiled for the last half-century since independence, the determinants of government's decision to invest in irrigation infrastructure are examined. Granger regression gives a strong support for the hypothesis that changes in the world rice price and the level of rice self-sufficiency induce the government to invest in irrigation infrastructure. In the sense that the decision to invest in irrigation infrastructure depends on the world rice price or the relative profitability of the investment that the world rice price determines, the decision making by the government in the allocation of public funds is said to be rational. Since independence, the goal of agricultural policy in the Philippines has been to supply sufficient amount of rice to urban consumers at reasonably low and stable prices, while saving foreign exchange as much as possible, in order to avoid urban unrest due to food shortage and to promote industrialization by maintaining low rice price and thereby low wage rates. It is observed that the consideration for food security and agricultural protection has been emerging as important policy concerns, as the vulnerability of the rice sector has swollen in the post-Green Revolution era since the mid-1980. The need to attain these policy goals has been behind the government rationality in investing in irrigation infrastructure. However, our study shows that this short-run rationality of the government does not insure the longrun efficiency in the resource allocation. Indeed, the irrigation sector in the Philippines has been underinvested in the last decade and half, and this shortrun rationality without long-run perspective in the allocation of public funds to irrigation infrastructure seems to be preparing food crisis in near future.