Agricultural impacts on water quality and implications for virtual water trading decisions

Research on the flow of virtual water associated with agricultural crop production and trade has focussed almost entirely on water quantity. It is pertinent to consider and quantify the opportunity costs in terms of reduced water quality associated with crop production. This paper investigates the impacts of water quality on virtual water trading by creating a proxy for water quality impacts by calculating the amount of water required to dilute nonpoint-source agrochemical inputs to relevant water quality guideline values. The quantity of water required for dilution of five agrochemicals (two nutrients; nitrogen and phosphorus and three insecticides; azinphos-methyl, chlorpyrifos and endosulfan) was estimated for five crops in South Africa (maize, wheat, sugar cane, citrus and cotton) and compared to consumption of irrigation water (blue water) and rainfall (green water) for the same crops. Results indicate that the volume of water required for dilution is similar to the total sum of green and blue water required for crop production, but significantly greater than blue water use (irrigation use). For all crops phosphorus losses require greater amounts of water for dilution than for nitrogen, while pesticides result in the greatest water quality use. Estimates of water quality use are based on assumptions for a number of input variables (i.e. fertilizer application rates, percentage loss of agrochemicals from cropped areas). A Monte Carlo analysis (5000 iterations) was run to randomly select input variables from within defined ranges. Water quality use was calculated and expressed as a factor of blue water use. For all crops the average factor indicated that the volume of water required for dilution of all agrochemicals was greater than that required for irrigation. The results of this study clearly indicate that the impacts of agriculture on water quality need to be considered in virtual water trading scenarios. The incorporation of a method to predict impacts on water quality provides a comparative tool which generates a more holistic frame of reference for decision making with regard to impacts on the water resource and virtual water trading.     

Adoption of safer irrigation technologies and cropping patterns: Evidence from Southern Ghana

The new irrigation technologies introduced in sub-Saharan Africa aim at ensuring safer vegetable production when untreated waste water is used as irrigation water. This paper examines the adoption of safer irrigation technologies and crop choices among vegetable farmers, using cross-section data from urban Kumasi in Ghana. The study employed a two-stage conditional maximum likelihood approach to examine the impact of crop choices and farm-level characteristics on the adoption of safer irrigation technologies. The empirical results indicate that apart from household and farm characteristics such as access to extension agents, belonging to a farmer's organization and education, cropping patterns tend to influence adoption of irrigation technologies for safer vegetable production.     

Local irrigation response to ethanol expansion in the High Plains Aquifer

Global ethanol production has grown rapidly due to national renewable fuel programs. Concern has grown over impacts that land conversion and crop displacement driven by ethanol feedstock production might have on water resources. In this paper, we examine irrigation decisions of agricultural producers in the Kansas portion of the High Plains Aquifer in response to local ethanol market expansion. To identify the effects of ethanol expansion on irrigation decisions, we examine field-level data on irrigation water use, irrigated acreage, and crop decisions for the years 2003–2017 for nearly 23,000 fields in Kansas. We measure the response of three irrigation decisions, (i) irrigated acreage, (ii) irrigation per acre, and (iii) total water use to the introduction and capacity expansion of an ethanol plant. We find that ethanol market expansion did lead to increases in irrigation water use. Specifically, a 10 % increase in ethanol capacity within 50KM increases annual water use by 0.22 % per field (4.8 acre-inches/field). We predict that ethanol markets accounted for about 4% of total irrigated water use in 2017.     

黑龙江省农业水资源利用研究

水是地球上一切生命赖以生存、也是人类生活和生产中不可缺少的基本物质之一。20世纪以来,由于世界各国工农业的迅速发展,城市人口的剧增,缺水已是当今世界许多国家面临的重大问题,尤其是城市缺水状况,越来越加剧。黑龙江省水资源属于中国北方较多地区,但降水分布不均,春旱和夏涝对农业生产影响较大。农业水资源丰富的地区,应优先发展水稻。农业水资源较少的地区发展旱田节水灌溉,应优先选择菜瓜果类高效益作物和对生产影响较大的种子苗木等。其次是扩大玉米催芽坐水种面积。第三是附加值较高的经济作物。     

Basin impacts of irrigation water conservation policy

Climate change, uncertain future water supplies, growing population, and increased water demands continue to raise the importance of finding cost-effective water conservation measures. Irrigated agriculture is the world's largest water user, so governments, donor organizations, water suppliers, and farmers continue to look for measures that would produce more crop per drop. Despite the importance of promoting water conservation in agriculture, little work has been done that integrates hydrologic, economic, institutional, and policy dimensions of water conservation. This paper presents an integrated basin scale analysis of water conservation subsidies for irrigated agriculture. A dynamic, nonlinear programming model is developed and applied for the Upper Rio Grande Basin of Colorado, New Mexico, and Texas, USA. Several potential public subsidies of drip irrigation are analyzed for their economic and hydrologic impacts at both the farm and basin levels. Results indicate that water conservation subsidies for drip irrigation produce several effects. These include greater on-farm implementation of water-conserving technology, less water applied to crops, more water consumed by crops, increased farm income, greater crop production, more land irrigated, and increased total water-related economic benefits for the basin. Findings provide a framework for designing and implementing water conservation policies for irrigated agriculture.     

Substitution between water and other agricultural inputs: Implications for water conservation in a River Basin context

Substitution of irrigation water with other agricultural inputs could be an important means to conserve water in the face of growing pressures on water resources from both nonagricultural water demands and environmental water requirements. This paper discusses the potential of such substitution through an empirical analysis based on a multiple-input crop production function at the field and farm scales complemented with a numerical modeling exercise at the basin scale. Results from the crop production function analysis show that under both crop yield and net profit maximization, water is a substitute to other crop inputs for high-value crops, and is a complement to water for low-valued crops. At the basin scale, an integrated economic-hydrologic river basin model is used to analyze the role of other factors in crop input substitution, including the spatial connections among water sources and demands, hydro-agronomic conditions, and institutional settings for water allocation. Results show that in the case study area, the Maipo River basin in Chile, where water is very scarce, moving from the current, input-constrained, situation to full optimization of water resources leads to an increase in all crop inputs, including water. In that case, 301 million m³ of additional water use results in additional net profits of USD 11 million. However, if the water fee is raised by a factor of eight while overall basin irrigation profits are maintained at the original, baseline level, a reduction of water withdrawals by 326 million m³ is traded off with costs of USD 43.2 million for other inputs. Irrigation districts with a high share of low-value crops have a low potential for substituting water with other crop inputs. Therefore, investments for water substitution should also be kept low in these areas.     

A dynamic analysis of water footprint of Jinghe River basin

Water footprint in a region is defined as the volume of water needed for the production of goods and services consumed by the local people, Ecosystem services are a kind of important services, so ecological water use is one necessary component in water footprint. Water footprint is divided into green water footprint and blue water footprint but the former one is often ignored.In this paper waterJootprint includes blue water needed by agricultural irrigation, industrial and domestic water demand, and green water needed by crops, economic forests, livestock prochtcts, forestlalands and grasslands. The study calculates the footprint of the Jinghe River basin in 1990, 1995, 2000 and 2005 with quarto methods. Results of research show that water footprints reached 164.1 ×10^8m3, 175. 69 ×10^8m3 and 178. 45 ×10^8m3 respectively in 1990, 1995 and 2000 including that of ecological water use, but reached 77.68×10^8m3, 94.24×10^8m3, 92.92×10^8m3 and 111.36 ×10^8m3 respectively excluding that of ecological water use. Green water.footprint is much more than blue water footprint; thereby, green water plays an important role in economic development and ecological construction The dynamic change of water footprints shows that blue water use increases rapidly and that the ecological water use is occupied by economie and domestic water use. The change also shows that water use is transferred from primary industry to secondary industry In primary industry, it is transferred from crops farming to forestry, and animal agriculture. The factors impelling the change include development anticipation on econonomy; government policies, readjustment of the industrial structure, population growth, the raise of urbanization level, and structurul change of consumption, low level of waler-saving and poor ability of waste water treatment.With blue water use per unit, green water use per unit, blue water use structure and green water use structure, we analyzed the difference of the six ecologieal function districts of the Jinghe River     

社会资本视角下农民用水户满意度研究——基于陕西省宝鸡峡灌区农民用水户的调查

以社会资本为研究视角,对社会资本维度进行划分,并运用有序Logistic模型,基于陕西省宝鸡峡灌区农民用水户的调查,研究农民用水户对农民用水户协会的满意度及影响因素。研究结果表明,结构维度和认知维度社会资本是影响用水户对协会满意度的重要因素,家庭收入水平、农业收入占家庭收入比重、渠系完好率、协会专业化程度以及用水户参与积极性对用水户满意度有显著影响;关系维度社会资本、用水户性别、年龄、文化程度对用水户满意度没有显著影响。这表明农民用水户协会主要承担着灌溉管理和农业发展的职能,而其承担的社会功能相对较弱。     

Modeling economic and agro-environmental dynamics of potato production systems

Crop rotation and other input management practices are of particular interest for their potential impacts on economic and agro-environmental components of potato production. Although crop yield and experimental impacts of rotations of grains, oilseed and legume crops have been published for several experimental studies in Canada there are few models related to the economic and environmental dynamics of potato production. We describe a dynamic model which integrates environmental and economic processes in potato production. The potato rotation model consists of interconnected modules of irrigation and precipitation, soil characteristics, soil erosion, soil water, phosphorus, nitrogen, soil organic matter, farming operations, crop yield and the related calculation of economic return. While not all aspects of crop production have been interlinked, including nitrogen carry-over, this model is the first step in the analysis of experimental data for irrigated potato rotations conducted in southern Manitoba.      

An economic model of waterlogging and salinization in arid regions

Waterlogging and salinization arise in arid areas largely because two essential resources, irrigation water and the assimilative capacity of unconfined aquifers, are not priced or allocated correctly to reflect scarcity values and opportunity costs. Farm-level and project-level models of crop production are examined to identify policies that will encourage farmers to consider opportunity costs and the effects of irrigation and leaching on depth to regional water tables. Appropriate policies include volumetric water pricing, water markets, tradable water allotments, adjustments in area-based cost recovery programs, and incentives for farmers to use irrigation methods that reduce deep percolation. Implementing appropriate versions of these policies may reduce the rate of increase in waterlogged and saline areas.     

Complementarity between water pricing, water rights and local water governance: A Bayesian analysis of choice behaviour of farmers in the Krishna river basin, India

To ensure efficient water allocation and use, policy designers have adopted various strategies, including price setting, decentralising irrigation water management or improving water rights. Most of these strategies have been applied individually, without considering the complementary relationships between them. This paper uses a discrete choice model to analyse the scope for combinations of tools for irrigation water demand management and farmers' acceptance of these. In terms of local irrigation water governance, the presence or absence of collective irrigation water management, in the form of a Water Users Association, is considered. Water rights are specified in terms of the duration and quality of the entitlement and its transferability. Finally, four types of water pricing methods (area, crop, block and volumetric pricing) are considered. Using a choice experiment, we elicit the most preferred water pricing method, under different water rights situations, at different price levels and under various contexts for local irrigation water governance. Our results indicated that under conditions of improved water rights, preference for volumetric pricing increases, whilst the presence of a Water Users Association reduces this preference. Furthermore, it was found that using an appropriate combination of water demand management tools considerably increases the willingness to pay for a change in scenario.     

An integrated analysis of the effects of local water institutions on irrigated agriculture outcomes in the arid western United States

Irrigation water rights and their governance structures constitute the foundation of local water institutions and profoundly influence water resource allocations, irrigated agricultural productivity and other consumptive water uses in the arid climate zones. This article explores the regional structures of irrigation water rights and water governance and empirically analyses the priority effects of water rights on irrigated agriculture at the micro level in Idaho, an arid and semiarid state in the western United States. We integrate a unique data set of water rights and water supplies with agricultural features and environmental characteristics into our empirical analysis. Results indicate that seniority in water resources allocation has significant, positive effects on both the average crop revenue and crop water use efficiency. Local water rights structures differ significantly in seniority and water sources from region to region. In response to the heterogeneity in local water rights structures, the aforementioned effect of allocative priority of water rights on average crop revenue per hectare and crop water productivity varies significantly, reaching up to an 87% difference, when measured across regions. In addition, the priority effects of water rights are nonlinear, which reflects the influence of historical patterns of water rights establishment on water institutions to date.     

干旱区绿洲农业发展节水灌溉合作经济组织的特征与作用

干旱区农业节水灌溉合作经济组织是节水灌溉技术应用过程中一种新的生产经营管理经济组织形式。运用组织理论对节水灌溉合作经济组织的内涵作了具体的定义,从组织目标、组织结构、组织方式等角度对合作经济组织的特征进行了分析,对其组织发展的作用也进行了分析,并在此基础上,对继续发展节水灌溉合作经济组织建设提出了一定的建议。     

宁夏平原天然状态下作物水分亏缺研究

本文以宁夏平原为案例,对天然状态下的农田水分平衡状况进行了深入的定量研究,采用长系列(1961～2001年)、短时段(月)和多种作物类型(8种)相匹配的操作方法,建立农田水量平衡模型,计算得到了宁夏平原各个县域单元、各种作物、逐年、逐月的有效降水、盈水量、亏水量值。结果表明:自然降水不能满足作物生长发育的需求,水分亏缺是宁夏平原天然状态下农田水分平衡的主要特征;不同作物水分亏缺程度差异较大;宁夏平原未来农业发展必须推行"以水定产"战略。     

江苏省水稻生产投入要素及影响因素实证研究

以江苏省最主要的粮食作物水稻为例,按照2004年分县纯收入水平,以该省22个县的354户水稻种植户2005年横截面数据为样本,运用扩展的C—D生产函数,就投入要素及品种认知、农业生产决策者个人特征等影响因素对水稻生产的作用进行了研究。估计结果显示：目前土地仍是影响江苏省水稻产出的最主要因素,化肥在水稻生产上仍发挥着重要作用。随着水稻良种良法配套栽培的推广,农户水稻品种认知对水稻生产的重要性得到显现。鉴于耕地灌溉条件对水稻生产的影响非常明显,政府应加大对农田水利设施的建设投入。     

Adoption of improved irrigation and drainage reduction technologies under limiting environmental conditions

Modern irrigation technologies have been suggested as a means of conserving scarce water and reducing environmental pollution caused by irrigated agriculture. This paper applies an economic model of technology selection that provides a general framework to analyzing adoption of irrigation technologies under various environmental conditions. Data from the San Joaquin Valley of California is used to verify the theoretical relationships. Results suggest key variables to be considered by policy makers concerned with adoption of modern irrigation technologies. Among these variables are crop prices, water technology costs, farm organization characteristics, and the environmental conditions of the farm or the field. Policy implications were discussed and analyzed.This research was conducted while the first author was a visiting scholar with the Dept. of Agricultural Economics, University of California, Davis, and USDA-ERS, USA.     

A study on the bioenergy crop production function of land use in China

Based on the analysis of the bioenergy crop production function of land use,combined with the status quo of Chinese land use,the cultivation of energy plants and the bioenergy crop production function of land use had been analyzes and discusses in this paper.Results show that there were a lot of unused lands and marginal lands which can be planted bioenergy crops to perform the bioenergy crop production function of land use with great potentials; and currently there were no food production problems.Therefore,it was very important for China to emphasize bioenergy crops planting in order to fully use land resources in our country,moderate the energy crisis and increase peasants＇ income.     

Sources of Mistrust: An Experimental Case Study of a Central Asian Water Conflict

With the disintegration of the USSR a conflict arose between Kyrgyzstan, Uzbekistan and Kazakhstan over the transboundary Syr Darya river. Upstream Kyrgyzstan controls the Toktogul reservoir which generates hydropower demanded mainly in winter for heating. Downstream Uzbekistan and Kazakhstan need irrigation water in summer, primarily to grow an export crop (cotton). Regional agreements obliging Kyrgyzstan to higher summer discharges in exchange for fossil fuel transfers from downstream riparians in winter have been unsuccessful, due to lack of trust between the parties. Striving for self-sufficiency in irrigation water, Uzbekistan initiated new reservoir construction. This paper examines their economic impact. We report a laboratory experiment modelling the Syr Darya scenario as a multi-round, three-player trust game with non-binding contracts. Payoff schemes are estimated using real-life data. While basinwide efficiency maximisation requires regional cooperation, our results demonstrate that cooperation in the laboratory is hard to achieve. Uzbek reservoirs improve cooperation only weakly and their positive impact is limited to low-water years.     

Modeling the short-run costs of changes in water availability in a desert city: a modified input-output approach

This paper investigates the impact of change in sectoral water supply on employment, value-added output, and indirect business tax, in Maricopa County, Arizona using input–output model. We developed extended modified input–output approach that incorporates each source of water as a separate sector, and that allows for substitution between water sources, and estimated the economic impact of a change in surface water supplies under two scenarios. Scenario I assumes that total water supply/use decreases by 1%, but the reduction comes only from surface water use, holding groundwater use constant. Scenario II assumes that surface water supply/use in all industries decreases by 1%, and the reduction in surface water use is replaced by the exact amount of more expensive groundwater. We found that the magnitude of economic impact depends on consumer’s responsiveness to water price change. When price elasticity of water demand is relatively low (≤0.2), the economic impact of a 1% reduction in surface water supplies was smaller than under the first scenario. However, the more water users in all industries are responsive to a change in water price, the bigger are economic impacts in terms of reductions in jobs, value added, and indirect business taxes.     

Fresh surface water resource allocation between Bulgaria and Greece

This paper addresses the important issue of transboundary sharing of fresh surface water resources, including quantity and quality dimensions. It carves a simple economic model of the benefits which can be generated by maximizing the joint profits earned, when the resource is shared efficiently between two countries. The appropriate policy instrument towards this end is a bilateral agreement to charge the same water price to all water users in a given sector. Market clearance will then follow to determine the optimal water price. The case of the Nestos river flowing through Bulgaria and Greece, but overexploited by Bulgaria, in the Balkans is used as a case study. The empirical estimation of a fixed proportions production function for corn derives a marginal water value of the Nestos water for Greece. This value, which applies under the current non-cooperative solution, is higher than the optimal water price in the cooperative solution.