Coping with drought with innovative pricing systems: the case of two irrigation water management companies in France

In recent years, France has been facing particularly severe drought periods especially in summer. In a country where agriculture is the largest water user, some irrigation management companies have implemented innovative pricing systems to handle this situation. The objective of this article is to analyze the impact of these new management systems on farmers’ incomes, the revenue of the management companies, and the amount of water used. To do that, we develop a methodology using a stochastic model that simulates the representative farmer's optimal behavior in a context of climatic variability. An empirical application is made with a crop growth model and data collected from the Midi‐Pyrenees region. The results show that using these specific nonlinear pricing systems allow irrigation water managers to reduce the impact of drought on production. Moreover, the type of pricing implemented depends on the characteristics and capabilities of the water company. More particularly, these pricing systems can be used to anticipate agricultural water demand in order to avoid imbalance with water availability.     

An empirical assessment of the value of irrigation water: the case study of Murrumbidgee catchment*

Evaluation of value of irrigation water is essential for supporting policy decision making relating to investments in the irrigation sector, efficient allocation of irrigation water and water pricing and for crafting policies to compare the variable impacts of water reform within and across sectors of the economy. This paper asks the question of how much an established irrigator would pay for water and at what price farmers planning to expand the area they have under irrigation would consider paying for the right to access water. An analytical framework is developed to estimate the net present value of both annual and perennial agricultural activities in the Murrumbidgee catchment. Using these estimates the total value of water used in Murrumbidgee catchment is estimated. An aggregate water supply curve is derived for the catchment from where water may be acquired from irrigators for environmental flows.     

Agricultural Landscape Value and Irrigation Water Policy

Water is a limiting factor of agricultural production in an increasing number of regions. There is also ample empirical evidence to suggest that the economic value of agricultural landscape is substantial, which has been used to justify agricultural support programs in developed economies. We investigate the link between the environmental amenity of agricultural landscape and the value of water in crop production. We find that the environmental externality gives rise to a social derived demand for water which differs from the market‐based (private) derived demand for water. Policy implications regarding irrigation water allocation and pricing are drawn. An empirical example illustrates the methodology and main findings.     

Assessing the Impact of Alternative Water Pricing Schemes on Income Distribution

The reform of water pricing policies may represent an effective instrument for enhancing the efficient use of water resource. However, policy makers fear that a change in the pricing methods may cause income loss for some farmers, and that this income inequality may generate public discontent and policy inertia. The aim of this paper was to compare some pricing methods in order to measure their effects on income distribution. The analysis focuses on the income distribution among different types of farms, and the income distribution between different social groups (landowners, capitalists and workers) in the short term. A linear programing model based on expected utility theory is used to take into account the effect of commodity prices and rainfall variability, which are among the most relevant factors affecting farmers’ income. According to the findings, water pricing schemes do not affect the income distribution among farm types, although a significant impact emerges on the distribution among social groups, and in particular on the wages of temporary workers.     

Water pricing policies,public decision making and farmers' response: implications for water policy

The problems caused by water scarcity demand important changes in the criteria and objectives of water policies. The agricultural sector in Spain consumes up to 80% of all available hydric resources and the need to increase the efficiency of current uses of water in the agricultural sector is at the core of the country's national water policy. One alternative would be to resort to water pricing policies with the aim of providing incentives to save water consumption although it would inflict a certain degree of income losses to the farmers and raise the revenue collected by the water authorities. The objective of this research is to analyze the effect caused by the application of different water pricing policies on water demand, farmers' income and the revenue collected by the government agency. To undertake this analysis a dynamic mathematical programming model has been built that simulates farmers' behavior and their response to different water pricing scenarios. Empirical application of the model has been carried out in several irrigation districts in Spain covering varied farm regions and river basins. Results show that the effects of alternative pricing policies for irrigation water are strongly dependent on regional, structural and institutional conditions and that changing policies produce distinct consequences within the same region and water district. Thus, equivalent water charges would create widespread effects on water savings, farm income and collected government revenue across regions and districts.     

辽宁农业灌溉用水影响因素时空差异性研究

目的 文章基于2000—2019年辽宁农业灌溉用水相关数据，将农业灌溉用水压力、效率、用水价格、种植结构等因素纳入农业灌溉用水需求模型，估计各影响因素对农业灌溉用水需求的影响，更好地保障粮食和水资源安全。方法 利用时空地理加权回归模型研究辽宁各地级市农业灌溉用水影响因素作用的时空差异性。结果 （1）不考虑影响因素作用的时空差异性，用水价格和农村居民人均收入变动对辽宁农业灌溉用水需求的影响特别小。（2）考虑到影响因素作用的时空差异性，除了朝阳和大连，其余各地级市农业灌溉用水需求的价格弹性在2014年前后呈现出负向增大的态势，水价改革还有较大的效力空间。（3）辽宁农业灌溉用水效率和种植结构的回归系数在空间上呈现出中部低，四周高的特点。（4）城镇化程度对农业灌溉用水需求的影响呈现出由东北向西南逐渐递减，由正向较强逐渐向负向较强的演变。结论 依据辽宁农业灌溉用水的各影响因素的作用强度，种植结构、用水效率和城镇化程度是影响辽宁农业灌溉用水需求的主要因素，合理制定城镇化规划对该因素回归系数呈显著上升趋势的地级市尤为重要。     

Macro–micro feedback links of water management in South Africa: CGE analyses of selected policy regimes

The pressure on an already stressed water situation in South Africa is predicted to increase significantly under climate change, plans for large industrial expansion, ongoing rapid urbanization, and government programs to provide access to water to millions of previously excluded populations. This article employs a general equilibrium approach to examine the economy‐wide impacts of selected macro and water‐related policy reforms on water use and allocation, rural livelihoods, and economy at large. The analyses reveal that implicit crop‐level water quotas reduce the amount of irrigated land allocated to higher‐value horticultural crops and create higher shadow rents for production of lower‐value water‐intensive field crops, such as sugarcane and fodder. Accordingly, liberalizing local water allocation within irrigation agriculture is found to work in favor of higher‐value crops, and expand agricultural production and exports and farm employment. Allowing for water trade between irrigation and nonagricultural uses fuelled by higher competition for water from urbanization leads to greater water shadow prices for irrigation water with reduced income and employment benefits to rural households and higher gains for nonagricultural households. The analyses show difficult trade‐offs between general economic gains and higher water prices, which place serious questions on subsidizing water supply to irrigated agriculture, i.e., making irrigation subsidies much harder to justify.     

GOVERNMENT POLICIES AND AGRICULTURAL SUPPLY RESPONSE: PADDY IN SRI LANKA

An aggregate analysis of supply response in the paddy (rice) sector of Sri Lanka during 1952-87 is conducted to identify the impact of pricing policy, irrigation programmes, institutional credit and concessional sales on area, yield and overall supply. The focus of the estimation procedure is the selection of an appropriate functional form for regressions and on the price variable that best represents the price to which producers respond in making area and yield decisions. In the case of both area and yield, the econometric criteria favour the acceptance of log-linear equations with the ratio of the guaranteed price of paddy to fertiliser price. On the basis of overall supply elasticity estimates, it is concluded that while pricing policy, irrigation programmes and institutional credit provide incentives to the expansion of paddy production, concessional sales of rice act as a disincentive.     

Agriculture’s Inter‐industry Linkages,Aggregation Bias and Rural Policy Reforms

As agricultural policy reform and its effects have become increasingly territorialised, analyses that attempt to explain or predict impacts need to be both more localised and to identify spill‐over effects. Local and regional general equilibrium approaches have become increasingly popular because they can extend predictions of policy shocks obtainable from partial equilibrium sectoral models to identify the wider effects. However, agriculture is usually described as a single sector in input–output accounts, whereas policy shocks that affect constituent commodities with differential impacts will have inter‐industry effects that are different to those implied by average input–output coefficients. Regionalisation of aggregated input–output tables adds further to these difficulties. The objective of this study is to develop a practical method for dealing with these problems. It describes the theoretical basis of aggregation bias and shows how it can be measured, in two contrasting case study regions in the UK and Sweden. Having established that this is a significant issue, a simple but effective procedure is demonstrated, based on additional information on variable costs, which transforms policy shocks from a direct change in agricultural output to that transmitted to the suppliers of inputs. This method provides an impact close to that which could be calculated if the general equilibrium system had indeed been disaggregated, and supports use of this approach in impact studies where insufficient time or funding are available for complete disaggregation of an agricultural sector’s regional accounts.     

Water scarcity and the impact of improved irrigation management: a computable general equilibrium analysis

Increasing water scarcity combined with an increasing demand for food and water for irrigation call for a careful revision of water use in agriculture. Currently, less than 60% of all the water used for irrigation is effectively used by crops. Based on the new version of the GTAP‐W model we analyze the effect of potential water savings and the welfare implications of improvements in irrigation efficiency worldwide. The results show that a water policy directed to improve irrigation efficiency led to global and regional water savings, but it is not beneficial for all regions. The final effect on regional welfare will depend on the interaction of several different causes. For instance, higher irrigation efficiency changes opportunity costs and reverses comparative advantages, modifying regional trade patterns and welfare. For water‐stressed regions the effects on welfare are mostly positive. For nonwater scarce regions the results are more mixed and mostly negative. The results show that exports of virtual water are not exclusive of water abundant regions.     

Block-Rate versus Uniform Water Pricing in Agriculture: An Empirical Analysis

In this article we adapt Burtless and Hausman's (1978) methodology in order to estimate farmers' demand for irrigation water under increasing block-rate tariffs and empirically assess its effect on aggregate demand and inter-farm allocation efficiency. This methodology overcomes the technical challenges raised by increasing block-rate pricing and accounts for both observed and unobserved technological heterogeneity among farmers. Employing micro panel data documenting irrigation levels and prices in 185 Israeli agricultural communities in the period 1992–1997, we estimate water demand elasticity at −0.3 in the short run (the effect of a price change on demand within a year of implementation) and −0.46 in the long run. We also find that, in accordance with common belief, switching from a single to a block-price regime, yields a 7% reduction in average water use while maintaining the same average price. However, based on our simulations we estimate that the switch to block prices will result in a loss of approximately 1% of agricultural output due to inter-farm allocation inefficiencies.     

Evaluation of drought management in irrigated areas

This paper focuses on the economic consequences of droughts for the irrigation sector. We develop a dynamic‐recursive mathematical programming farm model that assumes imperfect mobility of capital and labour as well as rational expectations about future water availability. The model is calibrated to 12 representative farms belonging to three irrigation communities of the Guadalquivir Basin (south Spain) and used to simulate the 1991–1997 period, which included 3 years of intense drought. Results indicate that the drought imposed significant costs on farmers, but show also that water managers partly exacerbated these costs by allocating excessive amounts of water to irrigators in the abundant years. The model is also used to evaluate the benefits of a perfect water supply forecast and to simulate the economic gains of a voluntary water banking scheme. Results show that the benefits resulting from the perfect forecast of water supply 1 year ahead would represent a relative gain of 5%. However, a voluntary banking system would allow farmers to increase their benefits by 32–82% depending on the supply system.     

The role of common pool problems in irrigation inefficiency: a case study in groundwater pumping in Mexico

Groundwater depletion is a serious problem in Mexico. Several policy alternatives are currently being considered in order to improve the efficiency of irrigation water use so that extraction of groundwater is diminished. An understanding and quantification of different sources of inefficiency in groundwater extraction is critical for policy design. Survey data from a geographically extensive sample of irrigators is used to gauge the importance of common pool problems on input‐specific irrigation inefficiency. Results show that mechanisms of electricity cost sharing implemented in many wells have a sizable impact on inefficiency of irrigation application. Moreover, irrigation is very inelastic to its own unitary cost. Therefore, results suggest that policies aimed at eliminating electricity cost‐sharing mechanisms would be significantly more effective than electricity price‐based policies in reducing irrigation application. Results also show that well sharing does not affect groundwater pumping significantly, suggesting either a limited effect of individual pumping on water level or absence of strategic pumping by farmers sharing the wells.     

鄂尔多斯市黄河南岸灌区农业水价改革实例分析

以内蒙古自治区鄂尔多斯市黄河南岸灌区农业水价改革为例,分析灌区农业水价改革的必要性和影响,并提出确定农业初始水权,构建农业水价形成机制,建立农业用水精准补贴和节水奖励机制以及健全完善灌区量水设施等改革措施。     

农业水价政策对农户种植结构的影响——以新疆地区为例

为了缓解用水危机,提高用水效率,中国正在推进农业水价综合改革,试图建立以水权交易为核心的水价制度。本文根据作物的亩均灌溉用水量将作物划分为高耗水作物和低耗水作物,利用新疆天山北麓5县(含2个团场和3个县)的农户调查数据,对比分析实施统一水价、阶梯水价、水权交易水价3种水价政策区域内农户的种植结构,探索农民在不同水价政策下的种植决策,并进一步验证价格信号对农户种植选择的影响。研究发现,由于水费收取方式和水价不同,实施不同的水价政策对农户的种植结构产生了不同的影响。与其他水价政策相比,水权交易水价更能促使农户选择更为节水的作物。不同水价政策下水的定价是影响农户选择种植结构的关键要素,当农户灌溉用水的机会成本增加时,他们会增加低耗水作物的种植比例。每亩低价水定额对农户选择种植低耗水作物有非线性的影响,当每亩低价水定额超过一定数量时,定额进一步增加会导致农户减少种植低耗水作物。     

目标价格补贴政策对棉花生产的影响分析基于PSM-DID的实证研究

目的 目标价格补贴政策是改革农产品价格形成机制的重要举措,对于优化我国农业供给结构具有重要的意义。方法 为了评估临时收储制改为目标价格补贴政策对新疆棉花生产的影响,文章基于2011—2018年新疆和其他棉花主产区县级棉花生产相关数据,运用双重差分倾向得分法（PSM-DID）分析了目标价格补贴政策对新疆棉花的种植面积和产量的总体影响、动态效应和区域效应。结果 目标价格补贴政策对调控国内棉花供给起着重要作用;该政策总体上促进了新疆棉花产业发展,棉花面积和产量显著提高;从政策的动态效应来看,目标价格政策调整为三年一定的方案对棉花生产的促进作用显著大于试点期一年一定的效应;此外,目标价格补贴政策对南疆和北疆的影响效应存在差异,对南疆棉花生产的促进效果更显著。结论 在此基础上,结合我国缺乏棉花定价权,目标价格补贴政策可能导致国家财政负担过重,且容易触及WTO黄箱补贴的限制等问题,该文提出了进一步完善目标价格补贴政策,逐步向脱钩的补贴方式过渡,并积极探索财政补贴与市场补偿相结合的补贴机制等相关建议。     

Effects on poverty and equity of the decline in collective tank irrigation management in Tamil Nadu, India

This paper investigates the factors influencing the decline in collective management of local commons and the impact of this decline on agricultural production and household consumption. The analysis is based on a village and household data set collected in 1999 in Tamil Nadu, India, where tank irrigation systems are managed collectively for rice cultivation by informal water users' organizations. Our statistical analyses find that one major reason for the decline in collective tank irrigation management is the dissemination of private well irrigation systems. Once the decline has occurred, our analyses predict that the gap in rice yields between farmers who have access to private wells and those who must rely solely on tanks will widen, with only the latter group suffering lower yields. Our analyses also find that the same pattern holds for levels of income and consumption because the affected farmers cannot sufficiently compensate for the loss of their rice income by diversifying their income sources to agricultural labor or nonagricultural work. In this way, the decline in collective management results in greater inequality and poverty.     

陕西省农业灌溉水资源保障程度及空间差异分析

[目的]文章选取2016年陕西省各市区农业灌溉水资源相关数据,分析其对粮食生产的影响,进而计算出陕西省及其各市区农业灌溉水资源对粮食生产保障程度,最终总结其存在的空间差异,并提出差异化的解决措施,以保障陕西省粮食安全。[方法]选用农业灌溉水资源保障度分析模型,针对陕西省各市区的水资源供需情况、粮食种植结构及产量和农作物灌溉情况,对陕西省及其各市区的农业灌溉水资源保障程度进行计算,研究其空间差异性。[结果]陕西省农业灌溉水资源保障度为101.84%,基本上能满足农业灌溉用水需求,但已迫近水资源供给紧张的边缘。陕西省农业灌溉水资源保障度呈显著的空间差异,关中地区农业灌溉水资源保障度P为82.20%,农业灌溉水资源轻度缺乏,属于资源型缺水现象;陕北地区农业灌溉水资源保障P为112.38%,影响该地区农业生产发展;陕南地区农业灌溉水资源保障P为145.92%,农业灌溉水资源丰富,灌溉耕地能够得到用水保障。[结论]农业灌溉水资源对粮食生产具有重要的作用,陕西省农业灌溉用水资源存在较大的空间差异性,需要参考不同地区的农业灌溉水资源保障度数值,采取不同的节水策略,以保障粮食安全生产。     

Do Differences in the Scale of Irrigation Projects Generate Different Impacts on Poverty and Production?

This article investigates differences in household production and consumption among small‐ and large‐scale irrigators to assess whether the scale of an irrigation project increases household welfare in Mali. Much of the evidence of the impact of irrigation does not use counterfactual analysis to estimate such impact or distinguish between the scale of the irrigation projects to be evaluated. In the dataset collected by the author, both a large‐scale irrigation project and small‐scale projects are used to construct counterfactual groups. Propensity score matching is used to estimate the average treatment effect on the treated for small and large irrigators relative to non‐irrigators on agricultural production, agricultural income and consumption per capita. Small‐scale irrigation has a larger effect on agricultural production and agricultural income than large‐scale irrigation, but large‐scale irrigation has a larger effect on consumption per capita. This suggests that market integration and non‐farm externalities are important in realising gains in agricultural surplus from irrigation.     

影响我国气候旱区粮食生产能力的灰色关联分析

文章根据投入产出分析的相关理论,结合其他学者的研究成果,确定了影响气候旱区粮食生产能力的主要因素。包括粮食作物播种面积、粮食作物种植结构、粮食单位面积产量、有效灌溉面积、农业从业人数、农用化肥施用折纯量、农业机械总动力及受灾面积、财政对粮食直接补贴资金额、年均降水量等。通过选取2000~2013年统计数据,运用灰色关联分析法,对这些因素与气候旱区粮食总产量进行相关性分析,表明财政对粮食直接补贴资金额、农用化肥施用折纯量、粮食单位面积产量、玉米播种面积占粮食作物播种面积比例及受灾面积与粮食产量高度相关,对提升粮食生产能力的影响较大;小麦播种面积占粮食作物播种面积比例、农业机械总动力、有效灌溉面积、农业从业人数、粮食作物播种面积、年均降水量都与粮食产量中度相关,对提升粮食生产能力的影响较小。因此应继续推行政府对粮食直接补贴政策、增加政府对粮食直补资金,同时,增加物质投入、提高农业科技水平、改善农业灌溉条件、调整粮食种植结构、提高粮食单位面积产量、减少受灾面积来提升粮食生产能力,增加粮食产量。