Improved Irrigation Technologies Research Articles

The enduring nature of cranberry production in a changing climate: The interplay of extreme weather, knowledge networks, and adaptation

Anthropogenic climate change is causing critical issues in agriculture, including cranberry production; however, in a previous study the majority of Massachusetts cranberry growers were less likely to see global warming as a threat than the general US population, and more still reported to be little worried about such warming. This research aims to determine the influence of weather and professional information disseminated to cranberry growers on their climate change adaptation. The authors used a mixed-methods, interdisciplinary approach, including content analysis of around 300 issues of UMass Extension’s Cranberry Station monthly newsletter—a widely trusted source of information in the cranberry grower “network of knowledge”—along with historical weather data from 1974 to 2020, and interview and survey data. Despite infrequent usage of direct communication on climate change and adaptation, UMass Extension’s communication on weather challenges in general showed a small but significant increase when monthly temperature anomalies increased. Meanwhile, anomalous monthly precipitation was negatively associated with total chemical mentions (linked to chemical use behavior). Climate impacts such as increased weeds, water issues (e.g., heavy rainfall, water scarcity), and heat waves ruining harvests were important to growers, leading to the adoption of both conventional (e.g., increased strategic flooding, barge sanding due to lack of ice) and emerging (e.g., smart irrigation, solar panel installations for added income) adaptive strategies. Growers demonstrate climate and technological optimism, believing that other growers are hit worse by climate change than themselves and that cranberry plant resilience, better weather forecasting, and improved irrigation technology will allow them to handle future weather challenges. The prioritization of immediate needs over the more abstract, long-term challenge of climate change by growers and the supporting system underscores the imperative to explore the socio-environmental dynamics that shape their climate responses in cranberry production.

Climate change adaptation strategies for sustainable water management in the Indus basin of Pakistan

Pakistan's agriculture faces water security challenges owing to insecure water supply and bad governance. The increasing food demand of the growing population and climate change vulnerability are future key threats to water sustainability. In this study, the current and future water demands as well as management strategies are evaluated for two climate change Representative Concentration Pathways (RCP2.6 and RCP8.5) for the Punjab and Sindh provinces in the Indus basin of Pakistan. The RCPs are assessed for the regional climate model REMO2015, which was found to be the best-fitting model for the current situation in a preceding model comparison using Taylor diagrams. The status quo water consumption (CWRarea) is estimated to 184 km3 yr−1, consisting of 76 % blue water (freshwater from surface water and groundwater), 16 % green water (precipitation), and 8 % grey water (required to leach out the salts from the root zone). The results of the future CWRarea indicates that RCP2.6 is more vulnerable than RCP8.5 in view of water consumption as the vegetation period of crops is reduced under RCP8.5. For both pathways (RCP2.6 and RCP8.5), CWRarea increases gradually in the midterm (2031–2070) and becomes extreme at the end of the long term (2061–2090). The future CWRarea increases up to +73 % under the RCP2.6 and up to +68 % in the RCP8.5 compared to the status quo. However, the increase in CWRarea could be restrained up to −3 % compared to the status quo through the adaptation of alternative cropping patterns. The results further show that the future CWRarea under climate change could be even decreased by up to −19 % through the collective implementation of improved irrigation technologies and optimized cropping patterns.

Assessment of future water demand and supply using WEAP model in Dhasan River Basin, Madhya Pradesh, India.

Understanding the available resources and the needs of those who use them is necessary for the evaluation and allocation of water resources. The main sectors utilizing the basin water resources are agriculture, drinking water, animal husbandry, and industries, and the efficient and rational management of water resources to be distributed among those different sectors of activity is vital. This study attempts to develop an integrated water resource management system for the Dhasan River Basin (DRB) by employing a scenario analysis approach in conjunction with Water Evaluation and Planning Model(WEAP) to analyze trends in water use and anticipated demand between 2015 and 2050, simulating five possible scenarios (I, II, III, IV, and V) as for external driving factors. For the WEAP modeling framework, 2015 was chosen as a current (base) year for which all available information and input data were given to the model and the future demand situation was analyzed for the period 2016-2050 (forecasting period). From the findings, it was observed that for the forecasting period, total water demand, unmet demand, and streamflow were 185.29 Bm3, 117.35 Bm3, and 58.26 Bm3, respectively, in the case of scenario I; 232.34 Bm3, 162.17 Bm3, and 59.87 Bm3 in case of scenario II; 139.40 Bm3, 84.37 Bm3, and 58.15 Bm3 in case of scenario III; 186.15 Bm3, 118.76 Bm3, and 56.98 Bm3 in case of scenario IV; and 181.89 Bm3, 96.87 Bm3, and 53.11 Bm3 in case of scenario V. Results of the study indicated that by 2050, increasing population growth, industrial development, and an increase in the agricultural area will rise the water demand dramatically, posing threats to the environment and humans. Therefore, implementing improved irrigation technologies, advancing agricultural practices on farms, and constructing water conservation and retaining structures could significantly reduce the unmet demands and shortfalls in DRB. Overall findings reveal that the pressure on the Dhasan water resources would increase in the future, and thus several suggestions have been provided to assist decision-makers in sustainable planning and management of water resources to meet future demands.

Assessment of suitable land for surface irrigation using spatial information systems: Case of Bilate River Basin in the Rift Valley Lakes Basin, Ethiopia

Identifying the limited available resource, use of improved irrigation technology and better water resources management have been suggested as mechanisms for increased production. To optimize the agricultural production, knowing the available land for irrigation is mandatory. This study aimed to assess the suitable land for surface irrigation using different spatial parameters (normalized difference vegetation index, soil, slope, proximity, rainfall deficit, and land use). Land suitability was assessed by considering the individual parameters and then by overlaying. The overlay suitability analysis was performed by using weighted overlay tool within spatial analyst tool in ArcGIS. After excluding the irrigation constraints suitable land for surface irrigation was identified. Based on the individual parameters analysis the normalized difference vegetation index gives the largest land size which is 95 % of the total land as suitable. While the slope factor gives the lowest figure which is 57 % of the total land is suitable for irrigation. The weighted overlay analysis, gives only 28.46 % of the total land in the basin was suitable for surface irrigation. More than 93 % of this suitable land is grouped in to small scale while only about 7 % is used for medium to large scale irrigation.

Factors Influencing Water Saving Measures and Water-Use Efficiency of Wheat Growers in Sindh, Pakistan

As the food supplies will have to be increased according to the growing population, water demand will be on the rise in the future. Therefore, improved water consumption patterns must be followed to match future food demands. The paper analyzes the farmer’s adoption of improved irrigation technology to avoid excessive irrigation water use in cultivating crops. In addition, this paper also investigated the factors influencing the water-use efficiency of the farmers. A total of 390 farmers who grew wheat crops were selected from the Naushahro Feroz and Benazirabad districts of Sindh, Pakistan. Socio-economic variables and efficiency scores of the respondents were taken as variables, and both binomial logistic and Tobit regression models were applied. Results indicated that household head’s experience and formal education have a positive and significant impact on their decision to adopt improved irrigation and their efficiency scores. The elasticities reveal that a 1 % increase in experience of farming possesses the probability of lining the water courses by 23%. Whereas, with the change of 1% in the formal education of respondents, the tendency to laser land leveling changed by 0.1%. In comparison, the distance of the farm from the canal and the area of the farm bears a negative impact on water conserving measures opted by them and their water-use efficiency scores. It was found that proper lining of the water courses, usage of drought tolerant varieties of crops, irrigation technology adoption, and laser land leveling were the measures taken to avoid the excessive use of irrigation water. These measures were found to significantly impact the water-use efficiency scores of sampled farmers. These findings might be helpful for researchers and policymakers to realize such factors influencing the adoption of farmers and their farm efficiency.

Rebound Effects in Irrigated Agriculture in Uzbekistan: A Stakeholder-Based Assessment

There is wide consensus among scholars and practitioners that improved irrigation technologies increase farm productivity and improve resource use efficiency. However, there is also growing empirical evidence that efficiency improvements in irrigation water use may create rebound effects, i.e., they may trigger changes in farmers’ behavior that partly or fully offset the technical water savings expected under ceteris paribus conditions. In extreme cases, total water consumption may even increase. We studied the impacts of introducing water-saving irrigation technologies in Uzbekistan and used structured stakeholder interviews for an expert-based assessment of potential rebound effects. Our findings contribute to the understanding of impacts of technological and institutional responses to environmental and economic pressures in sustaining water resources. The study demonstrates that although the objective of increasing irrigation efficiency may be achieved, the actual water savings under Uzbek conditions are likely to be reduced due to rebound effects. Unless there are effective policy interventions, we expect rebound effects through an increase in water supply for crops that compensates for current shortages of irrigation water availability, an increase in irrigated area, a switch to more water-intensive crops, and overall economic growth. The findings of this paper provide a reference point for estimating the water-saving potential and for evaluating and adapting policies.

Why Have Economic Incentives Failed to Convince Farmers to Adopt Drip Irrigation in Southwestern Iran?

Sustainable water usage is an important global concern and an urgent priority, especially in dryland regions such as Iran. The Iranian government is actively addressing the challenge of water scarcity by encouraging farmers to adopt new water application technology. Its main element to decrease water consumption is to encourage new irrigation systems, in particular drip irrigation. However, despite the benefits of drip irrigation technologies and the availability of generous government subsidies, adoption rates of the improved irrigation technology remain critically low among Iranian farmers. Therefore, this study seeks to determine what is limiting the uptake of improved irrigation technology in Iran. While it is well known that acceptance of new technology ultimately depends on multiple and interrelated factors, we examine those factors affecting farmers’ adoption from three theoretical perspectives in the adoption literature: farmers’ socio-economic characteristics, social capital, and technology characteristics. A cross-sectional survey was undertaken in Behbahan district in Khuzestan province in southwest Iran. The sample comprises 174 farmers who adopted drip irrigation in that region and 100 non-adopters who were located in the same region. Discriminant analysis reveals that a socio-economic approach is the strongest model to predict adoption of drip irrigation technology in the study area, followed by models of technical characteristics, and social capital. These results can help agricultural extension agents and policy-makers design appropriate and effective strategies that facilitate the adoption of drip irrigation at an increasing rate.

Sources of spatial variability of soil salinity: the case of Beni Amir irrigated command areas in the Tadla Plain, Morocco

The origins and spatial variability of salinity within irrigated plots are a constraint to good long-term field management. Regional depletion of groundwater resources, as well as soil salinization, have been reported in the Tadla plain, a key production area in Morocco. In the northwestern part, water supply is provided only by the local water table, whose evolution in level and salinity over the last 24 years has been analyzed. A mapping of 17 plots was carried out by electromagnetic induction (ECa) after calibration of the measurements with salinity (R 2 = 0.94). These plots are cultivated with different crops (wheat, olive, sugar beet, alfalfa, carrots) with little or no crop rotation, or left fallow. The results highlight two main factors of salinization. On the one hand, the type of crop leads to salinization that increases according to water needs, which are rarely satisfied, thus favoring the accumulation of salts in the upper part of the soil profile. This first factor explained 80 to 85% of the variance in ECa measurements. On the other hand, the gravity irrigation method associated with numerous leaks is responsible for an unequal distribution of water within the plots, associated with 15–20% of the variance. These results confirm the current unsustainable management of this hydro cultural system and highlight the need for better access to quality water and improved irrigation technology. A development proposal is briefly presented.

Economic and environmental impact assessment of sustainable future irrigation practices in the Indus Basin of Pakistan

Pakistan’s agriculture is characterized by insecure water supply and poor irrigation practices. We investigate the economic and environmental feasibility of alternative improved irrigation technologies (IIT) by estimating the site-specific irrigation costs, groundwater anomalies, and CO2 emissions. IIT consider different energy sources including solar power in combination with changes in the irrigation method. The status quo irrigation costs are estimated to 1301 million US$ year−1, its groundwater depletion to 6.3 mm year−1 and CO2 emissions to 4.12 million t year−1, of which 96% originate from energy consumption and 4% via bicarbonate extraction from groundwater. Irrigation costs of IIT increase with all energy sources compared to the status quo, which is mainly based on diesel engine. This is because of additional variable and fixed costs for system’s operation. Of these, subsidized electricity induces lowest costs for farmers with 63% extra costs followed by solar energy with 77%. However, groundwater depletion can even be reversed with 35% rise in groundwater levels via IIT. Solar powered irrigation can break down CO2 emissions by 81% whilst other energy sources boost emissions by up to 410%. Results suggest that there is an extremely opposing development between economic and ecological preferences, requiring stakeholders to negotiate viable trade-offs.

Measuring the effect of improved irrigation technologies on irrigated agriculture. A study case in Central Chile

Irrigated agriculture is the primary sector demanding water resources in the world. Given that, improved irrigation technologies could play a crucial role in enhancing water use efficiency. This paper uses causal inference estimators to evaluate the effect of these technologies on irrigators at the farm level in two irrigated valleys in Central Chile. Doubly robust estimators were employed to address the selection bias of the adoption of improved irrigation technologies. The results show first a low level of technology adoption, with only 18% of irrigators adopting irrigation, where access to credits and education plays a crucial role in their adoption. Despite this low rate, the estimates show consistently positive and significant impacts on adopters in terms of annual margins and land use. As a result, our research calls for attention towards focusing programs and policy targeting on reducing entry barriers and broadening the adoption of irrigation technologies, allowing to reduce the gap in terms of economic wellbeing and the long-term sustainability and adaptation to climate change of irrigated areas.

Modeling irrigation technology adoption and crop choices: Gains from water trading with farmer heterogeneity in Southern Alberta, Canada

In this paper, we modeled water trading in southern Alberta by incorporating irrigation technologies and crop choices. We consider six irrigation technologies and twelve crops with a variation in land quality to examine the adoption gains from water trading. The results are summarized to account for the gains from water trading and the probability of farmers switching to efficient irrigation technologies to cultivate profitable crops. Simulation results suggest that famers are more likely to follow rational adoption approach in using the gain from water trading to adopt efficient irrigation technologies. This is more likely to occur when the net gain is higher than the cost of adopting an irrigation technology. However, sensitivity analysis shows that high crop price regimes and provision of subsidies on the impact of water trading on technology adoptions could encourage farmers to adopt improved irrigation technologies to produce profitable crops. Effective policies to provide incentives to farmers to adopt efficient irrigation technologies and to improve crop yields may be necessary for the study area.

A Decade of Irrigation Water use trends in Southwestern USA: The Role of Irrigation Technology, Best Management Practices, and Outreach Education Programs

Irrigation water is crucial for farm operations in the world, with irrigated lands contributing about 40% to food and fiber production. In semi-arid regions such as the Southwestern United States, the demand for irrigation water has increased due to population growth, rising temperatures, and severe drought events in the region. Irrigation plays a vital role in the economies of southwestern states and requires comparative studies to understand the current situation and to propose possible improvement strategies. This study investigated the trend of irrigated cropland, the quantity of irrigation water use, irrigation technology, scheduling decisions, and irrigation outreach using data from 2007 and 2017 United States Department of Agriculture (USDA) National Agriculture Statistics Service (NASS) census. Harvested cropland in the region remained the same with minimal increase in total irrigated land (1%) and the quantity of irrigated water used (2%). However, gravity irrigation methods reduced significantly by 12%, with a 71% increase in the use of drip irrigation systems. The increase in the adoption of soil moisture sensors (55%), plant sensors (107%), government schedules (29%), and supplier’s schedules (50%) for irrigation scheduling decisions, did not translate to a reduction in irrigation water use at the regional level. However, at the state level within the same period, Arizona recorded an increase in irrigated cropland by 10% and harvested cropland by 9%, with a reduction in the quantity of irrigation water used (-5%). The gains in Arizona could be associated with the combined effects of improved irrigation technologies and the use of best management decisions, which could serve as a model for prudent water use in the southwest. There is a need to increase the effort in science-based education and extension programming on integrated approaches that emphasize both irrigation technology and the best management practices, which include seed selection for drought-tolerant crops.

Irrigation infrastructure and farm productivity in the Philippines: A stochastic Meta-Frontier analysis

Abstract Irrigation is a lynchpin of rural development strategies and a key input to improving productivity and farm incomes, the key source of livelihood for the majority of the world's poor. Limited land and growing water scarcity mean that establishing systems to maximise the benefits from every drop is pivotal. In this paper, we analyse the impact of a canal irrigation project for smallholders in the Philippines, focusing on rice, one of the world's most water intensive crops. We contribute to two strands of literature by combining impact evaluation and efficiency analysis methods. Using a dataset for 714 treatment and 440 control farm parcels, we apply Propensity Score Matching and a selectivity-corrected Stochastic Production Frontier to handle biases from both observable and unobservable variables. We then analyse technical efficiency (TE) and frontier output using a shared Stochastic Meta-Frontier. We find that the project had a statistically significant impact on frontier output but not on TE, suggesting that improved irrigation technology increased beneficiaries' production potential, but it did not improve TE likely due to insufficient training and input access. Thus, beneficiaries were unable to take full advantage of their improved production potential, highlighting the need for suitable complementary support in future projects. Heterogeneity analysis reveals that the main beneficiaries were downstream parcels, smaller parcels, those located in the poorer project district, and farmers with lower education, all implying a pro-poor impact. Finally, we find that female-headed households benefitted less from the project, suggesting the need for additional support in future interventions.

Water Resources Management Strategies for Irrigated Agriculture in the Indus Basin of Pakistan

Agriculture of Pakistan relies on the Indus basin, which is facing severe water scarcity conditions. Poor irrigation practices and lack of policy reforms are major threats for water and food security of the country. In this research, alternative water-saving strategies are evaluated through a high spatio-temporal water footprint (WF) assessment (1997–2016) for the Punjab and Sindh provinces, which cover an irrigated area of 17 million hectares in the Indus basin of Pakistan. The SPARE:WATER model is used as a spatial decision support tool to calculate the WF and establish alternative management plans for more sustainable water use. The average water consumption (WFarea) is estimated to 182 km3 yr−1, composed of 75% blue water (irrigation water from surface water and groundwater sources), 17% green water (precipitation) and 8% grey water (water used to remove soil salinity or dilute saline irrigation water). Sugarcane, cotton, and rice are highly water-intensive crops, which consume 57% of the annual water use. However, WFarea can be reduced by up to 35% through optimized cropping patterns of the existing crops with the current irrigation settings and even by up to 50% through the combined implementation of optimal cropping patterns and improved irrigation technologies, i.e., sprinkler and drip irrigation. We recommend that the economic impact of these water-saving strategies should be investigated in future studies to inform stakeholders and policymakers to achieve a more sustainable water policy for Pakistan.

FACTORS INFLUENCING IRRIGATED CABBAGE (BRASSICA OLERACEAE) PRODUCTION IN TORO LOCAL GOVERNMENT AREA OF BAUCHI STATE, NIGERIA

The study was conducted to examine the factors influencing irrigated cabbage production in Toro Local Government Area of Bauchi State, Nigeria. Multistage sampling technique was used to select a total of 100 farmers for the study. The data collected was analyzed using descriptive and inferential statistics. The result shows that all (100%) of the farmers were male and 35.7% of cabbage farmers were youth with average age of 35.6 years. The result further reveals that all (100%) of the respondents were male and majority (69.4%) of the farmers were literate who obtained various form of formal education. The average farm land cultivated was 1.5 hectares and 74.5% of the farmers acquired their inputs from the market. Majority (80.6%) of the farmers sourced water from the river/stream and used pumping machine for the irrigation. The result also shows that most (93.9%) of the farmers adopted treated and improved seeds technology. The result revealed that quantity of seeds, labour, fertilizer and farm size had positive coefficients and significantly influenced cabbage output. The R2 was estimated at 0.398 which implies about 40% of the variation in output of cabbage production was explained by explanatory factors included in the model. The R2 was estimated at 0.398 which implies about 40% of the variation in output of cabbage production was explained by explanatory factors included in the model. This is not by chance as justify by F-value of 10.027 and significant at P<0.001, indicating combine effect of independent variables on the total output. The study recommends that farmers should be encouraged to form cooperative societies to obtain input resources collectively and enjoy group marketing of cabbage. The use of more improved irrigation technologies is also recommended in order to boast cabbage production for high income.

Managing climate risks through transformational adaptation: Economic and policy implications for key production regions in Australia

Transformational adaptations are expected to become more frequent and widespread in Australia, and globally, with a changing climate. However, any transformation adaptation will have complex and interconnected effects on rural communities, particularly income, employment and service provision, which will impact on regional sustainability. This paper investigates regional transformative adaptation options to manage climate risks for the rice and cotton industries of northern Queensland, Australia. More specifically, it seeks to identify when to move from incremental adaptation to transformative adaptation and, more importantly, to assess the potential regional economic consequences of such a transformative adaptation. The results indicate transformative adaptation could have large negative effects on regional economies. Relocation of rice or cotton in sugarcane production system will not compensate some negative regional impacts. More importantly, the increase in wheat production in Riverina will not compensate for the reduction in the higher value rice commodity. However, the cotton production system in Queensland is capable of transformational adaptation and incremental adaptation with little impact on regional communities. In contrast, the southern rice production region of the Riverina shows limited capacity for incremental adaptation, given the already high adoption of improved irrigation technologies and practices, and the limited scope to improve these further. The market incentives for the transformation adaptation of cotton and/or rice production in north Queensland are limited without government support. Alternatively, there may be interest from international investors, which would shift the focus from market opportunities to international food security.

Tree Shelterbelts as an Element to Improve Water Resource Management in Central Asia

In Central Asia, agriculture, notably irrigated agriculture, is the largest water consumer. Currently, flood and furrow irrigation are the dominant irrigation methods in Central Asia, in particular in the post-Soviet countries. Against the background of current and increasing competition for water—e.g., through reduced river runoffs in the course of climate change—water consumption of agriculture needs to be reduced. On the field plot level, improved irrigation technologies, like drip irrigation or plastic mulch, can reduce water consumption substantially. Alternatively, tree lines as wind breaks (shelterbelts) also can reduce crop water consumption, as shown by research from many drylands around the world. As previous research has concentrated on crop water consumption and not on tree water consumption, this paper brings the two together, in order to approach a more holistic picture, in how far shelterbelt systems, including the trees, may have the potential to save water or not. Crop water consumption was assessed through the Penman–Monteith approach for corn, wheat, potato, barley, and pear under open field conditions and under an assumed influence of a tree shelterbelt. Tree water consumption was investigated through sap flow measurements. Crop water consumption was reduced by 10–12% under influence of a shelterbelt compared to open field conditions. When water consumption of shelterbelts was added, a slight reduction of water consumption of the whole crop-shelterbelt system was found for corn, potato, and pear under the assumption 25 ha (500 × 500 m) field sizes. Under an assumption of 4 ha (200 × 200 m) field size, water consumption of the whole crop-shelterbelt system was higher for all crops investigated except for pear. The results suggest that shelterbelts may play a role in improving water resource management in Central Asia in the context of water demanding crops, like corn or cotton. In further research, other effects of shelterbelts, like increased crop yields and additional income from trees, need to be investigated.

Water use in agro-pastoral livelihood systems within the Bulgan River watershed of the Altay Mountains, Western Mongolia

Watersheds in the arid and semi-arid regions of Mongolia are especially vulnerable to the effects of climate and land cover change, which will likely exacerbate the disparity between water availability and demand. This study was conducted to analyse land cover changes between 1972 and 2013 and to characterize the currently prevailing livelihood strategies and farming practices in the river oasis Bulgan sum, Western Mongolia. The Soil and Water Assessment Tool (SWAT) was used to simulate the water-use efficiency for the concerned Bulgan River watershed.Comparison of the two land cover maps (1972 and 2013) of the Bulgan sum river oasis showed a major change from natural rangeland to mostly built-up areas (+288%) and river water receiving sites (+594%). The Bulgan River watershed covers an area of 7409km2 and the river itself has a long-term annual average discharge of 9.53m3s−1. Overall, an area of 769ha was actively irrigated (2013). A total withdrawal of 555460m3 irrigation water was estimated, 86% of which was applied to hay fields (2013). The irrigation water productivity ranged from 5.38 (fruits of fruit trees) to 0.43 (hay) m3 kg−1 fresh matter yield and a related average income of 0.58 € per kg dry matter per m3. The SWAT model simulated an average evapotranspiration of 100mm and potential evapotranspiration of 993mm per year. Water-use efficiency varied from 11 to 52kg dry matter ha−1mm−1 for rangeland and wetland. Auto-irrigation (whenever plant growth drops below this threshold, the model will automatically apply water until field capacity is reached) and fertilization management simulated by the SWAT model increased yields of irrigated crops, vegetable, hay and fruit trees by about 46 and 77% on average. To enhance biomass productivity per unit water transpired and income per unit water applied, improved irrigation technologies and management practices would be needed.

Improving irrigation efficiency will be insufficient to meet future water demand in the Nile Basin

The Nile River Basin covers an area of approximately 3.2 million km2 and is shared by 11 countries. Rapid population growth is expected in the region. The irrigation requirements of Nile riparian countries of existing (6.4 million ha) and additional planned (3.8 million ha, 2050) irrigation schemes were calculated, and the likely water savings through improved irrigation efficiency were evaluated. We applied SPARE:WATER to calculate irrigation demands on the basis of the well-known FAO56 Crop Irrigation Guidelines. Egypt (67km3yr−1) and Sudan (19km3yr−1) consume the highest share of the 84km3yr−1 total (2011). Assuming today’s poor irrigation infrastructure, the total consumption was predicted to increase to 123km3yr−1 (2050), an amount far exceeding the total annual yield of the Nile Basin. Therefore, a key challenge for water resources management in the Nile Basin is balancing the increasing irrigation water demand basin-wide with the available water supply. We found that water savings from improved irrigation technology will not be able to meet the additional needs of planned areas. Under a theoretical scenario of maximum possible efficiency, the deficit would still be 5km3yr−1. For more likely efficiency improvement scenarios, the deficit ranged between 23 and 29km3yr−1. Our results suggest that that improving irrigation efficiency may substantially contribute to decreasing water stress on the Nile system but would not completely meet the demand. Study RegionThe Nile River Basin covers an area of approximately 3.2 million km2 and is shared by 11 countries. Rapid population growth is expected in the region. Study FocusRecord population growth is expected for the study region. Therefore, the irrigation requirements of Nile riparian countries of existing (6.4 million ha) and additional planned (3.8 million ha, 2050) irrigation schemes were calculated, and likely water savings through improved irrigation efficiency were evaluated. We applied a spatial decision support system (SPARE:WATER) to calculate the irrigation demands on the basis of the well-known FAO56 Crop Irrigation Guidelines. New Hydrological Insights for the RegionEgypt (67km3yr−1) and Sudan (19km3yr−1) consume the highest share of 84km3yr−1 (2011). Assuming today’s poor irrigation infrastructure, the total demand were predicted to increase to 123km3yr−1 (2050), an amount far exceeding the total annual yield of the Nile Basin. Therefore, a key challenge for water resources management in the Nile Basin is balancing the increasing irrigation water demand and available water supply.We found that water savings from improved irrigation technology will not be able to meet the additional needs of planned areas. Under a theoretical scenario of maximum possible efficiency, the deficit would still be 5 km3yr−1. For more likely efficiency improvement scenarios, the deficit ranges between 23 and 29km3yr−1. Our results suggest that improving irrigation efficiency may substantially contribute to decreasing water stress on the Nile system but would not completely meet the demand.

The Impact of Irrigation Capital Subsidies on Common-Pool Groundwater Use and Depletion: Results for Western Kansas

We examine the effects of irrigation technology subsidies using a model of inter-temporal common pool groundwater use with substitutable technology and declining yields from groundwater stocks, where pumping cost and stock externalities arise from the common property problem. We develop and simulate an optimal control analytical model parameterized for Sheridan County, Kansas, overlying the Ogallala aquifer. We contrast competitive and optimal allocations and account for endogenous and time-varying irrigation capital on water use and groundwater stock. In our analysis, we account for the labor-savings from improved irrigation technologies. We find that in the absence of policy intervention, the competitive solution yields an early period with underinvestment in efficiency-improving irrigation technology relative to the socially efficient solution, followed by a period of overinvestment. This suggests a potential role for irrigation capital subsidies to improve welfare over certain ranges of the state variables. In contrast to previous work, we find evidence that significant returns may be achieved from policy intervention. We simulate a policy scenario where an irrigation technology subsidy is implemented to explore whether such a program can capture significant portions of the potential welfare gain.