Economics of nutrient management in Asian rice systems: Towards increasing knowledge intensity

Although the increase in rice production during the Green Revolution era of the past three decades was based on increased irrigation and fertilizer use, technologies and policies to enhance fertilizer-use efficiency will be needed in most of the intensive rice production areas in the coming decades. In less intensive areas, opportunities exist for further increasing fertilizer use by reducing risk through cultivar improvement and better management. As opposed to simple 'blanket' recommendations, improved efficiency requires conditional 'if-then' types of rules. Such recommendations, to be acceptable to farmers, should not only be cost-efficient, but must also fit into the farmers' knowledge systems and provide them with enough flexibility for experimentation and learning. In addition to technologies, policy reforms such as the removal of fertilizer subsidies are needed to make nutrient-efficient practices economically profitable to farmers. (C) 1998 Elsevier Science B.V.