低效的水定价与节水激励

中文摘要

农民购买水时往往支付固定费用，而不是面对边际价格。我们利用在孟加拉国开展的两项随机对照试验，研究边际价格、节水技术采纳与用水量之间的关系。第一项试验表明，只有当农民面对边际价格时，该技术才能节约用水。第二项试验发现，鼓励农民自愿转为按小时抽水计费并不能节约用水。综合来看，当农民面对边际价格时，节水措施效果最佳；然而，仅仅提供采用边际定价的选项，并不足以促使农民进行节水投资和减少灌溉用水需求。（JEL O13、Q12、Q15、Q16、Q25）

Abstract

Farmers often buy water using fixed fees—rather than with marginal prices. We use two randomized controlled trials in Bangladesh to study the relationship between marginal prices, adoption of a water-saving technology, and water usage. Our first experiment shows that the technology only saves water when farmers face marginal prices. Our second experiment finds that an encouragement to voluntarily convert to hourly pumping charges does not save water. Taken together, efforts to conserve water work best when farmers face marginal prices, but simply giving an option for marginal pricing is insufficient to trigger water-saving investments and reduce irrigation demands. (JEL O13, Q12, Q15, Q16, Q25)