Phases of irrigation development in Asian tropics: A case study of the Philippines and Sri Lanka

Using data for the Philippines and Sri Lanka during the last five decades, we examine three phases of agricultural development experienced by the rice sector in insular countries in tropical monsoon Asia; the first was based on land opening, the second on new irrigation construction and the third on increasing the efficiency of the existing irrigated land base. We show that these sequential shifts were induced by changes in the relative profitability of the three major means of land development for increasing food production. Rehabilitation, water management improvement and better maintenance, which are important means of irrigation development in the latest phase, are under-invested, despite their high rates of return.