Substitutability of Freshwater and Non‐Freshwater Sources in Irrigation: an Econometric Analysis
研究了农民在递增阶梯水价下，用处理过的废水和微咸水替代淡水灌溉的决策，发现两种水源的边际替代率等于1，且以色列的配额交换政策提高了农业产值和利润。
Population growth is increasing the scarcity of freshwater for irrigation and accelerating its replacement with non‐freshwater sources such as treated wastewater and brackish water. Although these substitutes may be less productive agronomically, their supply is usually more stable. We develop a structural econometric framework to assess the substitution between fresh‐ and non‐fresh water as it is inferred from water‐use decisions of farmers under increasing block‐rate water pricing. We employ the model to village‐level panel data from Israel, in which 50% of the freshwater allotments were replaced during the 1990–2010 period by treated‐wastewater quotas, using a non‐freshwater/freshwater volumetric exchange rate of 1.2. Based on our estimation results, the hypothesis that the marginal rate of substitution between the two water sources is equal to one cannot be rejected. Simulations suggest that the Israeli quota‐exchange policy has increased both agricultural production value and farming profits.