Climate change, characterized by rising temperatures and limited precipitation, has intensified the demand for irrigation water while simultaneously restricting its availability. This challenge poses significant risks to agricultural and food production, particularly in the Mediterranean regions where, recently, water deficits have led to substantial production losses and quality issues. Water is a critical determinant of crops' economic viability, especially for water-intensive crops, making it essential to estimate its economic relevance, especially in the absence of reliable water market prices. This study has two primary objectives: first, to evaluate the shadow price of irrigation water for maize grain at the farm level, which is defined as the value generated by the marginal unit of water consumed; and second, to analyse its heterogeneity. Leveraging a Farm Accountancy Data Network (FADN) panel of 1625 Italian farms over a decade (2010–2020), an econometric production function approach is employed. Moreover, quantile regressions reveal variations in the shadow price linked to geographical, managerial, and structural farm characteristics. Our findings underscore water’s key role in economically viable maize grain production, significantly enhancing the productivity of other inputs like fertilizers and pesticides. The average shadow price is 0.29 €/m³, with a median of 0.20 €/m³ and water total productivity accounts for one-third of maize’s average gross output. Quantile regressions uncover how factors like geographic location, altitude, farm management, irrigation water source, and farm size influence the distribution of water productivity, reflecting either efficient use or scarcity of this resource. Our estimation provides valuable insights for policymakers by offering accurate shadow price estimates for irrigation water in Italian maize grain production. Furthermore, it enhances our understanding of irrigation water’s role in the economic viability of this crop, while contributing to support evidence-based water management strategies, identifying vulnerable areas and farms and allowing for future methodological developments.

中文翻译：

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灌溉水经济价值和生产力：意大利玉米粮食产量的计量经济学估算

以气温上升和降水有限为特征的气候变化加剧了对灌溉用水的需求，同时限制了灌溉用水的供应。这一挑战给农业和粮食生产带来了重大风险，特别是在地中海地区，最近，该地区的缺水导致了严重的生产损失和质量问题。水是作物经济活力的关键决定因素，特别是对于水密集型作物而言，因此有必要估计其经济相关性，特别是在缺乏可靠的水市场价格的情况下。本研究有两个主要目标：第一，评估农场层面玉米籽粒灌溉水的影子价格，其定义为消耗边际单位水所产生的价值；其次，分析其异质性。利用十多年来（2010-2020 年）1625 个意大利农场的农场会计数据网络 (FADN) 小组，采用计量经济生产函数方法。此外，分位数回归揭示了与地理、管理和结构农场特征相关的影子价格的变化。我们的研究结果强调了水在经济上可行的玉米粮食生产中的关键作用，显着提高了化肥和农药等其他投入品的生产力。平均影子价格为 0.29 欧元/立方米，中位数为 0.20 欧元/立方米，水总生产力占玉米平均总产量的三分之一。分位数回归揭示了地理位置、海拔、农场管理、灌溉水源和农场规模等因素如何影响水生产力的分布，反映了这种资源的有效利用或稀缺性。我们的估算通过提供意大利玉米粮食生产中灌溉水的准确影子价格估算，为政策制定者提供了宝贵的见解。此外，它增强了我们对灌溉水在该作物经济可行性中的作用的理解，同时有助于支持基于证据的水管理战略，确定脆弱地区和农场，并为未来的方法发展做好准备。