Search

12 Pags.- 9 Figs.- 2 Tabls., The suspension of eroded soil in surface runoff ultimately leads to the transfer of nutrients to land and water resources. Placing soil or straw (as a barrier) inside irrigated furrows in order to reduce water flow velocity, as a traditional local practice, has not been investigated from the environmental point of view. In this research, the effect of micro-dams (barriers built inside the irrigated furrows, also known as tied ridges or furrow dikes) on the reduction of soil and phosphorus losses was investigated. Field experiments were performed in four consequent irrigation events. Two erosive inflow discharges (0.6 and 0.9 L/s) and two micro-dam distances (10 and 20 m) were implemented as test treatments. A control treatment, without micro-dams, was used for comparison purposes. For the discharge of 0.6 L/s, micro-dams reduced furrow soil loss by 25% and 33% for distances of 20 and 10 m, respectively. For 0.9 L/s, soil loss was reduced by 25% and 59% for distances of 20 and 10 m, respectively. Micro-dams also reduced dissolved phosphorus losses in runoff water by 13% to 37%, depending on discharge and distance, as compared to the control treatment. Micro-dams can effectively reduce water, soil and phosphorus losses., This work has been supported by the Center for International Scientific Studies & Collaboration (CISSC), Ministry of Science, Research and Technology, Iran.

13 Pags.- 4 Tabls.- 9 Figs., Surface irrigation, particularly furrow irrigation, is the most common method of water application into agricultural lands. Despite all its advantages, furrow irrigation has some demerits, such as a potential large volume of runoff losses. In this research, an approach was proposed to reduce runoff losses and to improve water flow characteristics by creating micro-dams, barriers inside the irrigated furrows. To control water flow and increase infiltration into the soil, experimental micro-dams were created at distances of 10 and 20 m, with a height of 5 cm. Field experiments were conducted at the research farm of the College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran in summer of 2018. Two erosive inflow rates (0.6 and 0.9 L/s) were considered. Furrow length and spacing were 100 and 0.75 m, respectively. Results indicated that micro-dams increased the advance time, leading to increased infiltration. Micro-dams also increased the recession time, due to the increase in overland water volume. Moreover, results showed that in treatments with micro-dams, runoff was reduced by up to 45.3% in comparison to the control treatment. The change in furrow cross-sectional area during the irrigation event was also reduced. Micro-dams showed a great potential to reduce irrigation runoff losses, and should be considered as a management practice aiming at water and soil conservation., This work has been supported by the Center for International Scientific Studies & Collaboration (CISSC), Ministry of Science, Research and Technology, Iran.

45 Pags.- 12 Figs.- 4 Tabls. The definitive version is available at: https://www.sciencedirect.com/science/journal/03783774, he impact of zebra mussel (Dreissena polymorpha) colonization on pressurized irrigation systems is becoming important in many areas of the world. If the infestation is not controlled, the conveyance capacity of the network reduces and mussels can completely block the system, preventing irrigation. A methodology to assess zebra mussel infestation in collective pressurized networks based on monitorization and hydraulic simulation is developed in this research. Normalized pressure, defined as the difference between simulated and measured pressure, is an indicator of the presence of zebra mussels (Morales-Hernández et al., 2018). When this variable is combined with the distributed discharge of the irrigation network, it is possible to use an optimization procedure to produce a roughness map of network pipelines. Roughness in excess of that characteristic of the pipeline material can be directly associated zebra mussel infestation. Different objective functions, optimization algorithms and strategies are proposed in this work, with the aim of attaining constant discharge-independent normalized pressure at each observation point in the network. Roughness values under different pipe conditions, reproducing levels of zebra mussel infestation, were experimentally obtained at a reference laboratory. The limitations and uncertainties of the proposed methodology are discussed. Normalized pressure was validated in an irrigation network belonging to a water users association, using continuous data recorded at different observation points during a complete irrigation campaign. The non-invasive hydraulic method has been designed to identify infested areas in real time and to optimize the chemical treatments controlling mussel development, This work was supported by the State Agency of Research of the Government of Spain (Agencia Estatal de Investigación) through grant AGL2017-89407-R and by the European Agricultural Fund for Rural Development (EAFRD) and the Government of Aragón. Both institutions funded the IRRIZEB II (Programa integral para el control y mitigación del impacto de la plaga de Mejillón Cebra en sistemas de regadío II) grant of the Plan de Desarrollo Rural (PDR).

48 Pags./ 3 Tabls./ 10 Figs. The definitive version is available at https://link.springer.com/journal/271, The energy of sprinkler irrigation drops splashing on the soil surface or the crop canopy depends on their size and velocity. The kinetic energy of sprinkler irrigation drops is a major factor degrading the soil surface. The effect of a growing maize canopy on sprinkler drop energy dissipation and water partitioning was analyzed. A field experiment was performed on a solid-set sprinkler irrigated plot cropped with maize. Measurements were performed at different locations and heights into the sprinkler layout. Tests were performed at five maize heights. At each maize height, drop population characteristics and pluviometry were measured above and below the maize canopy. Drop population was measured with an optical disdrometer. Catch-can devices were used to measure pluviometry. Solid-set sprinkler irrigation distributes water quite homogeneously, but drop characteristics largely differ between layout locations. The effect of the crop on drop characteristics intensified as the canopy height increased. The canopy cover reduced drop diameter more than it reduced drop velocity. As the canopy grew, its capacity to intercept and derive irrigation water to stemflow increased. The largest part of energy dissipation by the maize canopy took place in the top 1.5 m. A fully developed maize canopy reduced the drop kinetic energy reaching the soil to 13.6% of that reaching bare soil. As a management practice, in sensitive soils or in sprinkler systems applying water with high specific kinetic power, irrigation of bare soils should be avoided., State Research Agency of the Government of Spain (Agencia Estatal de Investigación) through grant AGL2017-89407-R

42 Pags.- 4 Tabls.- 11 Figs. The definitive version is available at: https://www.sciencedirect.com/science/journal/03783774, Zebra mussel (Dreissena polymorpha) colonies are becoming a real problem in pressurized irrigation networks. The zebra mussel infestation of the 45 Water Users Associations (WUAs) of the Riegos del Alto Aragón (RAA) irrigation project (121 thousand hectares located in northeastern Spain) was assessed during the period of 2013–2017. Maps of WUA infestation stages were produced. A survey of the WUAs made it possible to assess the relevance of certain structural and management practices in the control of zebra mussels. A method to monitor zebra mussel colonization of pressurized collective irrigation networks was presented. The method is based on the combination of pressure measurements at network hydrants and hydraulic simulations. Normalized pressure, estimated as the difference between simulated and observed pressure, should approach zero in all hydrants in a properly characterized, non-infested network. A positive normalized pressure can indicate the presence of zebra mussel colonies. The methodology was validated using two different test cases located in two RAA WUAs: the first case involved a discrete chemical treatment, while the second case was based on the analysis of three years of telemetry pressure data and remote operation of network hydrants. The existence of an infested reservoir upstream of the WUAs was the most likely source of zebra mussel colonization of the WUA pressurized networks in the RAA project. The desiccation and chemical treatment of the small WUA reservoirs was associated with pest control. The hybrid (measurement-simulation) methodology is able to characterize the presence of zebra mussel colonies in specific reaches of pressurized irrigation networks., This work was supported by the European Agricultural Fund for Rural Development (EAFRD) and by the Government of Aragón. Both institutions funded the IRRIZEB (Programa integral para el control y mitigación del impacto de la plaga de Mejillón Cebra en sistemas de regadío) grant of the Plan de Desarrollo Rural (PDR).

34 Pags.- 7 Tabls.- 1 Fig. The definitive version is available at: https://www.sciencedirect.com/science/journal/03783774, A decades-long policy for irrigation Telemetry and Remote Control (TM/RC) systems in Spain has led to installations for approximately 260 Water Users Associations (WUAs), with a total estimated area of 1.0 M ha of agricultural land. This is believed to be the largest deployment of such technologies in the world. These systems have been installed in financial cooperation between public administrations and WUAs. This paper set out to characterize these systems, assess the causes for their individual success or failure, consider their future evolution and support policy updates. A survey with 110 questions was addressed to 84 WUAs distributed throughout the country. Further, an interview with four questions was addressed to 24 selected stakeholders intervening in irrigation TM/RC projects: from policy makers to farmers. The results provide a detailed overview of these systems in Spain, characterizing the WUAs in which they are installed, their technological traits, their maintenance, the problems they face in their daily operation, their current use, the factors limiting wider use, and the willingness of the WUAs to continue bearing the costs to use TM/RC features in the future. A large majority of TM/RC systems are regularly used to improve WUA water and energy management, and receive proper maintenance. However, in 15% of WUAs, farmers are not satisfied with the TM/RC system, and in 19% of the WUAs the TM/RC system cannot operate half of the hydraulic valves connected to them. We found that early technology applications failed more than recent applications, evidencing a process of technological maturity. The standardization of TM/RC systems, adaptation of the system to WUA specificities, training of WUA personnel, and a sufficiently long guarantee period stood as critical variables for success in the implementation of these technologies., This work was supported by the Spanish State Research Agency (Agencia Estatal de Investigación) of the Ministry of Economy and Competitiveness (MINECO) of the Government of Spain, grant numbers: AGL2013-48728-C2-1-R, AGL2014-59747-C2-1- R, AGL2014-59747-C2-2-R, RTC-2015-3453-2 and RTC-2016-4972-2.

51 Pags.- 4 Tabls.- 12 Figs. The definitive version is available at: https://www.sciencedirect.com/science/journal/03783774, Reducing the working pressure at the sprinkler nozzles is one of the alternatives to reduce energy requirements in solid-set sprinkler irrigation systems. Previous studies reported ≈10% lower seasonal Christiansen uniformity coefficient (CUC) for low-pressure treatments than for standard treatments, but no differences in maize yield. This research analyses the effect of maize canopy water partitioning on irrigation performance indexes (CUC and wind drift and evaporation losses, WDEL). Three irrigation treatments were considered, based on the working pressure: 1) A standard brass impact sprinkler operating at a pressure of 300 kPa (CIS300); 2) A standard brass impact sprinkler operating at a pressure of 200 kPa (CIS200); and 3) A modified plastic impact sprinkler (with a deflecting plate attached to the drive arm) operating at a pressure of 200 kPa (DPIS200). Irrigation performance was measured using a catch-can network located above the maize canopy (CUCac, WDELac) along the whole crop season and using stemflow and throughfall devices below the maize canopy (CUCbc, WDELbc) in eight irrigation events. Maize growth, yield and its components were measured. Under low-wind and fully developed canopy conditions (a frequent situation for maize irrigation), CUCbc resulted higher than CUCac for the low-pressure treatments, while the opposite was observed for the standard pressure treatment. Maize canopy partitioning reduces the differences in irrigation performance indexes between pressure treatments, explaining why there are no differences in grain yield between them. Caution should be used when measuring sprinkler irrigation performance above tall canopies, since the elevation of the catch-cans and the crop canopy partitioning affect performance estimations., This research was funded by the Minister of Economy, Industry and Competitiveness (MICINN) of the Government of Spain through grant AGL2013-48728-C2-1-R. Octavio Robles has a scholarship funded by the Minister of Economy and Competitiveness of the Spanish Government.

The large diversity of irrigated agricultural areas hinders the development of social consensus and complicates decision-making about the allocation of investments for irrigation modernization. A classification of irrigated areas permits the identification and mapping of different categories and reveals the strengths and weaknesses of each category regarding specific criteria. This paper proposes a binomial (genus and species) classification methodology of irrigated areas, which was designed based on a participatory approach. Four internal properties determine the genus: type of water source, type of water energy, on-farm irrigation method and water availability. Four external properties classify the variability within each genus into species: land tenure, crop type, existence of an environmental protection figure and socio-economic level. The words used for the genus and specific name arise from the concatenation of syllables representing the state or level of each property. The method was applied to the irrigated area of the Ebro river basin in the Aragón region of Spain (ERB-Aragón). A total of 435,851 ha were classified. A large part of the irrigated land uses surface water (94 %), does not have water availability problems (80 %), is not affected by environmental protection figures (97 %), is devoted to field crops (86 %), and manifests a low (45 %) or moderate (41 %) socio-economic level. A total of 24 genera and 126 species were identified. The two most representative genera are SurGraFloVe (31 %) and SurPumPreVe (27 %), and the two main species are SurGraFloVe DisCeNoLo (19 %) and SurPumPreVe ConCeNoMo (19 %). These species received the local names of “Ribera del Ebro” and “Alto Aragonés” to facilitate policy discussions. The application of the method to the ERB-Aragón provides a privileged insight that can support policy analyses and guide institutional intervention. The proposed methodology can be adapted to other areas of the world by adjusting criteria and categories to local conditions., This research was funded by the Department of Agriculture, Livestock and Environment of the Regional Government of Aragón through the Rural Development Programme grant GGO2017E03200.

27 Pags.- 2 Tabls.- 17 Figs. The definitive version is available at: https://link.springer.com/journal/271, Despite the development of pressurized irrigation systems in the second half of the twentieth century, surface irrigation continues to be the most used system in the world. Computer tools are required to support performance improvements leading to its sustainability. A simulation model of basin/border irrigation is presented in this paper combining two-dimensional overland hydraulics based on Saint–Venant equations with three-dimensional infiltration based on the mixed form of Richards’ equation. The coupling of these equations is attained by enforcing continuity of pressure at the soil surface. The model applies a finite-volume approach using the diffusion-wave approximation form of the shallow water equations. Water flow on undulated topographies is simulated using a non-orthogonal curvilinear coordinate system. An underrelaxed-modified Picard iteration algorithm is used for Richards’ equation, and an underrelaxed Picard iteration algorithm is used for Saint–Venant equations. The model was validated using experiments from the literature. Model performance was robust and accurate, even in complex theoretical cases with strong soil-surface undulations. Mass conservation was judged satisfactory in all cases, with the long-term ratio of mass balance error in the order of 10−2 in the most complex simulations. Soil type, mesh non-orthogonality, and the interaction of these variables had a strong effect on CPU time. Additional research will be required to transform this simulation model into an operational tool for surface irrigation. Attention will need to be paid to additional surface irrigation systems, soil types, and the optimization of computational speed.

52 Pags.- 1 Tabl.- 13 Figs. The definitive version is available at: https://link.springer.com/journal/271, Numerous methodologies have been developed to characterize sprinkler irrigation drops with the purpose of improving irrigation efficiency and controlling soil erosion and compaction. This paper presents the laboratory characterization of the morphology and velocity of drops in their free-falling trajectory as influenced by drop diameter and wind speed. For this purpose, a particle tracking velocimetry technique with in-line volumetric illumination was implemented. Hypodermic needles were used to produce droplets of uniform size. Two needle diameters resulted in drops with average diameters of 1.94 and 2.94 mm. Drops were illuminated with a double-pulsed laser beam or an LED lamp. Drop characterization reached an elevation of 4.28 m and occasionally attained terminal velocity. Motion blur was suppressed using a deconvolution filter. Drop equivalent diameter, velocity, chord ratio, canting angle and trajectory angle were determined using an ad-hoc software. The experimental approach led to the measurement of real drop size by illuminating a volume in the capture zone; drop shape ranged from quasi-sphere to ellipsoid. Drop deformation was more intense under high wind speeds. Ballistic simulations of drop fall were performed using sphere and ellipsoid drag force models. Both models resulted in excellent agreement with measured drop velocity, with the ellipsoid model performing marginally better. The robustness of the experimental equipment, particularly in combination with the developed LED lamp, announces future outdoor applications in real sprinkler irrigated fields. Such applications will provide insight on the governing processes, and data sets for the improvement of sprinkler simulation models., Thanks are due to the Centro Interamericano de Recursos del Agua from the Universidad Autónoma del Estado de México, to the Universidad Autónoma de Zacatecas and to Aula Dei from the Consejo Superior de Investigaciones Científicas for the collaboration and support provided for the publication of this paper. Thanks are also due to CONACYT for providing a scholarship to Jesús Ramiro Félix-Félix to pursue doctoral studies.

Pags.- 1 Tabl.- 9 Figs. Published online: 7 June 2014. The definitive version is available at: http://link.springer.com/journal/271, A variety of techniques have been proposed in the literature for sprinkler drop characterization. An optical particle tracking velocimetry (PTV) technique is proposed in this paper to determine drop velocity, diameter and angle. The technique has been applied to the drops emitted by an isolated impact sprinkler equipped with two nozzles (diameters 3.20 and 4.37 mm) operating at a pressure of 175 kPa. PTV has been previously used to determine the velocity vector of different types of particles. In this research, PTV was used to photograph sprinkler drops over a region illuminated with laser light. Photographs were taken at four horizontal distances from the sprinkler, which was located at an elevation of 1.65 m over the soil surface. Drop angle and velocity were derived from the displacement of the drop centroid in two images separated by a short time step. Centrality and dispersion parameters were obtained for each drop variable and observation point. Results derive from the analysis of 2,360 images. Only 37.5 % of them (884 images) contained drops which could be processed by the PTV algorithm, resulting in a total of 3,782 drops. A filtering algorithm just validated 1,893 valid drops, which were successfully analyzed. The proposed technique uses expensive equipment requiring continued protection against irrigation water. This methodology has proven valuable to characterize irrigation water drops. Despite its robust measurement procedure, further comparison with other techniques seems necessary before this optical technique can be recommended for practical use in sprinkler drop characterization., Thanks are due to the Centro Interamericano de Recursos del Agua from the Universidad Autónoma del Estado de México and to the Maestría en Ingeniería Aplicada Orientación Recursos Hidráulicos of Universidad Autónoma de Zacatecas. Thanks are also due to CONACYT for providing a scholarship to Cruz Octavio Robles Rovelo to pursue Master Degree studies.

41 Pags.- 3 Tabls.- 11 Figs. The definitive version is available at: https://link.springer.com/journal/271, More than one million hectares have undergone irrigation modernization in Spain during this century. Irrigation modernization to pressurized systems is currently facing challenges derived from increasing electricity prices and decreasing public subsidies. The economic viability of such projects is compromised, and the number of projects is decreasing. Pressurized collective networks are commonly designed and managed using hydraulic simulation tools and probabilistic hypotheses on hydrant use. In this paper, a simulation tool is presented that widens the scope of the analysis by combining hydraulics with agronomy, agrometeorology, solid-set sprinkler irrigation and economics. The CINTEGRAL software simulates the net benefit of the seasonal operation of a collective pressurized irrigation network. The software incorporates an optimization module for the electricity contract associated with the pumping station. CINTEGRAL runs on a time step of a half-hour, and simulates the irrigation season of a variety of crops. The software was applied to analyze the economic benefit of a Water User Association (WUA) under different design and management scenarios (on-demand, network sectoring and dividing the irrigated area in separate networks). In the studied WUA, the network sectoring scenario provided important energy savings (22%) but negatively affected yield by a similar economic magnitude. The division of the area in two independent networks was the most cost-effective scenario. Network topologies, cropping patterns, market prices, irrigation infrastructure, soil conditions and management rules determine the optimum WUA management options. CINTEGRAL is a comprehensive simulation tool designed to help designers and managers guarantee the economic viability of their projects., Research was funded by the Ministry of Economy and Competitiveness of the Spanish Government (Plan Estatal de I + D+i) through Grant AGL2013-48728-C2-1-R. The International Center for Advanced Mediterranean Agronomic Studies of Zaragoza (CIHEAM-Zaragoza) provided an M. Sc. scholarship to Mr. El Habib El Malki.

42 Pags.- 5 Tabls.- 8 Figs. The definitive version is available at: http://www.sciencedirect.com/science/journal/03783774, Water and energy are limited and expensive resources. Conserving water and energy is a requirement to ensure the viability of modern pressurized irrigation systems. The objective of this research was to analyze the possibilities of reducing the nozzle operating pressure of impact sprinklers from 300 kPa (standard pressure) to 200 kPa (low pressure) in solid-set irrigation systems without reducing the sprinkler spacing and maintaining crop yield. Three treatments resulting from combinations of sprinkler type, and working pressure were analyzed: 1) Conventional impact sprinkler operating at 300 kPa (CIS300); 2) Conventional impact sprinkler operating at 200 kPa (CIS200); and 3) Modified deflecting plate impact sprinkler operating at 200 kPa (DPIS200). A randomized experimental design was applied to a maize crop during two seasons (2015 and 2016). Irrigation performance was measured by catch-can monitoring at one replicate of each treatment. Maize growth, yield and its components were measured. Differences between treatments in soil water, maize growth and yield variables were analyzed using ANOVA. Seasonal irrigation uniformity evaluated at the top of the canopy was larger for the standard pressure treatment (93%) than for the low pressure treatments (82% and 84% for DPIS200 and CIS200, respectively). The average wind drift and evaporation losses for the 2016 irrigation season were higher for the CIS300 treatment (17%) than for the low pressure treatments, DPIS200 (15%) and CIS200 (13%). Low pressure treatments did not reduce grain yield compared with the standard pressure treatment. Differences in irrigation performance and maize yield between the low pressure treatments, DPIS200 and CIS200, were not statistically significant. The reduction in energy use by reducing the operating pressure from 300 kPa to 200 kPa would allow to increase the net farming benefit of individual and collective systems. This is particularly true if low pressure irrigation is considered at the design phase of the irrigation system., This research was funded by MICINN of the Government of Spain through grant AGL2013-48728-C2-1-R. Octavio Robles has a scholarship funded by the Minister of Economy and Competitiveness of the Spanish Government.

This study is targeted to improve surface irrigation performance of durum wheat in swelling soils. For this purpose, furrow and border irrigation trials were carried out and evaluated under different soil water depletion rates, furrow spacing and unitary inlet discharges. Irrigation was triggered whenever the soil water depletion rate reached a predetermined threshold. A comprehensive irrigation evaluation produced hydraulic, agronomic and economic indicators, such as application efficiency, distribution uniformity, crop yield, gross margin and water productivity. Experimental results showed that supplied water depths exceeded soil water deficits, inducing relevant vertical and lateral water losses. Al- though border and furrow irrigation crop yields were virtually tantamount (about 5.5 Mg/ha), furrow irrigation was the system of choice. An irrigation strategy based on a furrow spacing of 150 cm, an inlet discharge of 2 l/s/furrow and a soil water depletion rate of 30% required a gross water depth of 4300 m3/ha/yr and generated an optimum crop yield of 58 qx/ha. In the analyzed range of soil water depletion, the gross margin and water value amounted to 1064 - 1390 Tunisian Dinar per hectare (TD/ha) and 0.39 - 0.44 TD/m3, respectively, for a furrow spacing of 150 cm.

46 Pags., 3 Tabls., 10 Figs. The definitive version is available at: http://www.sciencedirect.com/science/journal/01681699, Software con manual de uso en: http://hdl.handle.net/10261/45608, This paper presents a real-time, on-farm irrigation scheduling software (RIDECO). The software was been designed for stone fruit orchards in the semiarid conditions of Spain. The characterization of stone fruit crop water requirements for the local conditions and under different irrigation strategies is presented. Meteorological data in the study area is collected daily from the SIAR public network of weather stations in an automated fashion. Subsequently, values of cumulative degree-days are computed to identify the stages of fruit growth and crop development. The software allows performing weekly irrigation schedules under standard, regulated deficit irrigation and water restriction conditions. The irrigation scheduling software stands as a valuable tool for on-farm water resources allocation planning. It can be used to forecast the irrigation water required to meet seasonal meteorological, agronomical and managerial scenarios in stone fruit orchards. RIDECO can also be used to plan deficit irrigation strategies in cases of severe water restrictions. The software can be parameterized to adjust to specific varieties and local farming conditions. A variety of graphs assist irrigation managers in their decisions., The authors sequence in this paper follows the “first-last-author-emphasis” norm. This research was funded by the Plan Nacional de I+D+i of the Government of Spain through grant RIDECO-CONSOLIDER CSD2006-00067.

10 Pags., 6 Figs., 7 Tabls., Irrigation uniformity and wind drift and evaporation losses (WDEL) are major concerns for the design and management of sprinkler irrigation systems under arid or semi-arid conditions. Field trials were carried out to assess irrigation uniformity and WDEL under various wind velocities, sprinkler spacings and operating pressure heads. Based on experimental data, a frequency analysis was performed to infer the occurrence probability of a given uniformity coefficient (UC). In addition, statistical regressions were used to model WDEL as a function of different climatic variables. Increasing the operating pressure head improved uniformity at low wind speeds. It was shown that UC has been severely impaired at wind speeds above 4 m/s. In the prevailing wind conditions, the frequency analysis showed that a sprinkler spacing of 12 m × 12 m provided the best uniformity. In the local conditions, it is recommended to stop irrigation when wind velocity exceeds 4 m/s. Moreover, it was shown that wind speed and relative humidity were the main significant variables influencing WDEL., The authors are thankful to the INRGREF for the valuable support of this research.

44 Pags., 5 Tabls., 7 Figs. The definitive version is available at: http://www.springerlink.com/content/0342-7188/, Sprinkler kinetic energy has been linked to a number of problems in irrigated fields. This work presents the characterization of sprinkler drop kinetic energy and specific power from low-speed photographic drop data using a commercial impact sprinkler and three operating pressures. The spatial variability of specific power (W m−2) was assessed for different sprinkler spacings, showing different patterns in rectangular and triangular spacings. The specific power uniformity coefficient ranged from 38–77%, depending on sprinkler spacing and operating pressure. An attempt was made to characterize specific power from estimated (measured diameter and estimated velocity) and simulated data (using a ballistic model). While estimated data produced adequate results, simulated data resulted in a large overestimation. Discrepancies in kinetic variables between measured and simulated drop data permit to conclude that it is important to continue experimental drop characterization efforts as well as sprinkler simulation model development., This research was funded by the Agencia Española de Cooperación Internacional para el Desarrollo (AECID). Thanks are also due to the Universidad Autónoma de Zacatecas, México.

44 Pag., 3 Tabl., 3 Fig. The definitive version is available at: http://www.sciencedirect.com/science/journal/03783774, This study analyzes the effects of irrigation modernization on water conservation, using the Riegos del Alto Aragón (RAA) irrigation project (NE Spain, 123354 ha) as a case study. A conceptual approach, based on water accounting and water productivity, has been used. Traditional surface irrigation systems and modern sprinkler systems currently occupy 73% and 27% of the irrigated area, respectively. Virtually all the irrigated area is devoted to field crops. Nowadays, farmers are investing on irrigation modernization by switching from surface to sprinkler irrigation because of the lack of labour and the reduction of net incomes as a consequence of reduction in European subsidies, among other factors. At the RAA project, modern sprinkler systems present higher crop yields and more intense cropping patterns than traditional surface irrigation systems. Crop evapotranspiration and non-beneficial evapotranspiration (mainly wind drift and evaporation loses, WDEL) per unit area are higher in sprinkler irrigated than in surface irrigated areas. Our results indicate that irrigation modernization will increase water depletion and water use. Farmers will achieve higher productivity and better working conditions. Likewise, the expected decreases in RAA irrigation return flows will lead to improvements in the quality of the receiving water bodies. However, water productivity computed over water depletion will not vary with irrigation modernization due to the typical linear relationship between yield and evapotranspiration and to the effect of WDEL on the regional water balance. Future variations in crop and energy prices might change the conclusions on economic productivity.

The evolution of water governance and societal perception in large, public irrigation systems in developing countries has triggered successive waves of reforms since the 1980s. Among them are Participatory Irrigation Management, Irrigation Management Transfer, Public-Private Partnerships or Market Instruments. Reforms have generalized the implementation of Water Users Associations (WUAs) in continuous interaction with a public Irrigation Agency. This paper set out to review recurrent problems and reported solutions in the governance of irrigated areas in developing countries and to relate solutions to problems in a case study context. The combination of literature review and the experience of the authors permitted identification and characterization of eight problems and eight solutions. A semi-quantitative approach was designed to relate solutions to problems in case study WUAs. The approach is based on the definition of a generic problem-solution matrix and a WUA-specific problem vector. The solution vector indicates the adequacy of each solution to a case study WUA. It can be obtained by multiplying the problem vector with the problem-solution matrix. Application of this approach to seven case study WUAs demonstrated its potential. Local fine-tuning of the coefficients defining the problem-solution matrix seems required to draw conclusions effectively guiding decision-making., To CSIC Agency (Spain) for support.

32 Pag., 12 Fig., 1 Tabl. The definitive version is available at: http://cedb.asce.org/, Furrow fertigation can be an interesting practice when compared to traditional overland fertilizer application. In the first paper of this series, a model for furrow fertigation was presented. The simulation model combined overland water flow (Saint-Venant equations), solute transport (advection-dispersion), and infiltration. Particular attention was paid to the treatment of junctions present in level furrow systems. In this paper, the proposed model is validated using five furrow fertigation evaluations differing in irrigation discharge, fertilizer application timing, and furrow geometry. Model parameters for infiltration and roughness were estimated using error minimization techniques. The error norm was based on observed and simulated values of advance time, flow depth, and fertilizer concentration. Model parameters could be adequately predicted from just one discharge experiment, although the use of more experiments resulted in decreased error. The validated model was applied to the simulation of a level furrow system from the literature. The model adequately reproduced irrigation advance and flow depth. Fertigation events differing in application timing were simulated to identify conditions leading to adequate fertilizer uniformity.

The final version is available at: http://cedb.asce.org/cgi/WWWdisplay.cgi?0880019, The effect of reduced corn evapotranspiration (ET) during solid-set sprinkler irrigation on application efficiency was analyzed on two subplots. During each irrigation event, one subplot was irrigated (moist treatment) while the other was not (dry treatment). ET (weighing lysimeter) and transpiration (heat balance method) rates were determined at each subplot before, during, and after the irrigations. During daytime irrigations, there was a significant decrease in ET (32 – 55%) and transpiration (58%) for the moist treatment. After the irrigations (1 – 2 h), ET significantly increased (34%) and transpiration decreased (20%). Gross wind drift and evaporation losses (WDELg) were found to be 19.3% of the applied water. Taking into account the ET changes during and after the irrigations, net sprinkler evaporation losses (SELn) were 14.4 – 17.5% of the applied water. During nighttime irrigations, changes in ET and transpiration were almost negligible, and SELn were slightly greater than WDELg (9.5 and 8.1%, respectively, of applied water). SELn was mainly a function of wind speed. Reduced ET and transpiration during daytime irrigations moderately increased solid-set sprinkler application efficiency., This work was supported by grant AGL-2004-06675-CO3-02 (PN I+D+I, Ministerio de Educación y Ciencia of Spain).

11 pags.- 6 Figs.- 1 Tabl., Este trabajo presenta una aplicación de la herramienta de simulación CINTEGRAL que permite adaptar el diseño de la red de riego a la realidad agraria local de las zonas regables (meteorología, suelos, cultivos y productividad global). Se estudian las condiciones locales (meteorología, suelos y cultivos) de una zona regable del Valle Medio del Ebro cuya red se ha diseñado de forma estándar. Se analiza el efecto de la variabilidad meteorológica y de diferentes alternativas de gestión del riego sobre la productividad global de la zona. Se discuten las diferencias en producción y productividad global de la zona bajo tres alternativas de gestión del riego: 1) gestión a la demanda, 2) gestión en turnos de riego coincidentes con pisos de presión, y 3) gestión en dos redes independientes. Los resultados obtenidos muestran un efecto claro de la variabilidad meteorológica sobre los ingresos brutos, ingresos netos y la factura eléctrica. La gestión del riego en turnos ajustados en función de la presión requerida permite ahorrar el 22% en la factura eléctrica respecto de la gestión del riego a la demanda. Sin embargo, las producciones se ven afectadas de forma muy notable, reduciendo notablemente la productividad de la zona. Para mantener la productividad con un riego a turnos es necesario realizar modificaciones en el diseño original de la red. Por lo tanto, en esta zona la gestión en turnos coincidentes con pisos de presión no mejora los ingresos netos. La división de la red global en dos sub redes independientes de riego reduce la factura eléctrica en un 20% y además mantiene los niveles de producción, por lo que los ingresos netos se incrementan en un 9%., 11 pags.- 6 Figs.- 1 Tabl. Creative Commons License Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

The definitive version is available at: http://www.sciencedirect.com/science/journal/03783774, In the last decade irrigation districts in the Ebro Valley of Spain have started to use database applications to enhance their management operations. Such applications often put more emphasis on administrative issues than on water management issues. A new irrigation district management software called “Ador” is presented in this paper. This database application has been designed to overcome limitations identified in an analysis of the software used in the study area. Ador can be used in irrigation districts independently of the type of irrigation system (surface, sprinkler or trickle) and the type of irrigation distribution network (open channel or pressurised). It can even be used in irrigation districts combining different types of irrigation systems and different types of irrigation distribution networks. The software can be used with minimum district information. The goals are to manage detailed information about district water management and to promote better on-farm irrigation practices. Ador is currently used to enhance management of 62 irrigation districts accounting for some 173,000 hectares in the Ebro Valley., National Plan for Research and Development of the Government of Spain (AGL2000-0151-P4-02). FEDER II of the European Union (2FD97-0547-C02). I3P program of the European Union. Oficina del Regante (Government of Aragón, FEOGA funds of the European Union).

49 Pags., 1 Tabl., 1 Fig. The definitive version is available at: http://ascelibrary.org/toc/jidedh/130/6, The development of a coupled crop model (Ador-Crop) and solid set sprinkler irrigation model (Ador-Sprinkler) is reported in this work. The crop model incorporates many of the features developed in the well-known CropWat model. Improvements include the use of thermal time and the input of daily ET0. The solid set sprinkler model applies ballistic theory to determine water distribution resulting from water droplets subjected to a wind vector. Regarding the validation of the coupled model (AdorSim), the plot of soil available water versus measured and simulated yield reduction resulted in similar features. AdorSim explained 25% of the variability in measured yield reduction. Most of the unexplained variability is due to the effect of nonwater-related factors affecting crop yield. In a companion paper, AdorSim is used to investigate optimum water management options in the middle Ebro basin in the NE of Spain., This research was sponsored by the Research and Development program of the Ministry of Science and Technology of the Government of Spain and the FEDER funds of The European Union, through grant 2FD97-0547, and by the CONSI+D of the Government of Aragón, through grant P028/2000. The International Agency of Cooperation (Government of Spain) awarded a research scholarship to F. Dechmi.

40 Pags., 2 Tabls., 9 Figs. The definitive version is available at: http://ascelibrary.org/toc/jidedh/130/6, In this work, applications of the coupled solid set sprinkler irrigation and crop model AdorSim introduced in the companion paper are presented. The sprinkler irrigation model is based on ballistic theory, while the crop model is based on CropWat. AdorSim was used to evaluate the effect of sprinkler spacing on seasonal irrigation water use (WU) and crop yield. The most relevant results were related to the characterization of advanced irrigation scheduling strategies. The differences in crop yield and WU derived from irrigating at different times of the day were estimated for two locations strongly differing in wind speed. Irrigation guidelines were established in these locations to relate gross water use and water stress induced yield reductions. Simulations were also applied to estimate adequate wind speed thresholds for irrigation operation. In the experimental conditions, thresholds of 2.0 - 2.5 m s-1 proved effective to control yield reductions and to minimize WU., This research was sponsored by the Research and Development program of the Ministry of Science and Technology of the Government of Spain and the FEDER funds of The European Union, through grant 2FD97-0547, and by the CONSI+D of the Government of Aragón, through grant P028/2000.

32 Pags.- 3 Tabls.- 7 Figs. The definitive version is available at: http://www.sciencedirect.com/science/journal/03783774, In this work, a Fixed Spray Plate Sprinkler (FSPS) and two Rotating Spray Plate Sprinklers (RSPS) were compared in terms of wetted diameter, wind drift and evaporation losses (WDEL), static water precipitation pattern and dynamic water application profile. An experimental irrigation machine reproducing a pivot section was constructed and used to perform experiments in static and dynamic (linear displacement) modes. Water application from FSPS often resulted in a bi-modal pattern, while RSPS produced bell-shaped or triangular patterns. At a nozzle elevation of 2.4 m and an operating pressure of 140 kPa the wetted diameter was 1.6 m larger for the RSPS than for the FSPS. The differences between the two RSPS amounted to 0.5 m on the average. Reducing the nozzle elevation from 2.4 to 1.0 m resulted in a 2.6 m decrease in the wetted diameter. The use of RSPS may result in reduced surface runoff losses, due to the increased wetted diameter and the reduced peak precipitation rate. WDEL for RSPS were statistically related to wind speed, although no significant differences were found between both types of RSPS or between the two nozzle elevations. According to the experimental results, reducing the nozzle elevation will not result in reduced WDEL, but will increase the chances for runoff., This research was funded by the CONSI+D of the Government of Aragón (Spain) through grants P08/96 and P028/2000.

7 Pags.- 7 Figs. 1 Tabl. The definitive version is available at: http://ascelibrary.org/journal/jidedh, The level-furrow irrigation system consists of furrowing a level basin. In level furrows, irrigation proceeds just like in level basins: the field is flooded from one point and water spreads to irrigate each furrow. Several writers have reported that this irrigation system has the potential to conserve water as compared to level-basin irrigation. However, no comparative studies on the performance of both irrigation systems are available, and the simulation of level furrows has not been attempted. In this work, two field experiments are reported. Both of them were performed in the same soil and in the same conditions. In the first experiment, infiltration was estimated for a series of furrow irrigation discharges and for a level basin. In the second experiment, a level furrow irrigation event was evaluated. A simulated level basin irrigation event in the level furrow experimental field required six times more time and water to complete advance. Infiltration equations including the irrigation discharge or the wetted perimeter as independent variables were proposed for the experimental furrow conditions. Application of a furrow simulation model to the level–furrow experiment resulted in an underestimation of the time of advance. To overcome this problem, a simulation model for level furrows was developed and is presented in a companion paper. The reported field experiments were used to validate the model, which was applied (in a companion paper) to explore adequate conditions for level furrow irrigation performance.

A field experiment was performed to study the effect of the space and time variability of water application on maize (Zea mays) yield when irrigated by a solid set sprinkler system. A solid set sprinkler irrigation layout, typical of the new irrigation developments in the Ebro basin of Spain, was considered. Analyses were performed (1) to study the variability of the water application depth in each irrigation event and in the seasonal irrigation and (2) to relate the spatial variability in crop yield to the variability of the applied irrigation and to the soil physical properties. The results of this research showed that a significant part of the variability in the Christiansen coefficient of uniformity (CU), and wind drift and evaporation losses were explained by the wind speed alone. Seasonal irrigation uniformity (CU of 88%) was higher than the average uniformity of the individual irrigation events (CU of 80%). The uniformity of soil water recharge was lower than the irrigation uniformity, and the relationship between both variables was statistically significant. Results indicated that grain yield variability was partly dictated by the water deficit resulting from the non-uniformity of water distribution during the crop season. The spatial variability of irrigation water depth when the wind speed was higher than 2 m s−1 was correlated with the spatial variability of grain yield, indicating that a proper selection of the wind conditions is required in order to attain high yield in sprinkler-irrigated maize.

In this work, the Loma de Quinto irrigation district, located in Zaragoza (Spain) was characterised, and water use (WU) was assessed. The study was performed to contribute to the diagnostic analysis phase of an incipient management improvement process in this sprinkler-irrigated district. The objectives of this first paper of the series include: (1) characterising the irrigation systems, soil types and crops; (2) evaluating irrigation performance through the relationship between on-farm WU and net irrigation requirements (NIR); (3) identifying factors affecting on-farm WU. In order to accomplish these objectives, statistical analyses of field data, district records on WU and farmers' interviews were performed. Technical deficiencies were detected in solid-sets, centre-pivots and linear-moves. A seasonal irrigation performance index (SIPI), defined as the percentage of NIR to seasonal water billing, was determined at each plot and for each of the three study years. The average inter-annual SIPI amounted to 127%, indicating that crops in the district were consistently water stressed. An analysis of the SIPI for the main crops in the district revealed that water stress was more intense in drought resistant and/or heavily subsidised crops (SIPI for sunflower was 142%). The average irrigation interval (12.3 days) and irrigation depth (44 mm) were too high for some of the soils in the district. Farmers adjusted the irrigation interval to meet the seasonal change in irrigation requirements. The irrigation depth was reduced in windy days. In two of the three study years, large plots used less water than small plots, at a rate of about -5 mm ha-1. The high cost of irrigation water in relation to crop revenues, the technical deficiencies of the irrigation systems, and the limitations imposed by climate and soils appeared to be major causes of local water management problems. In a companion paper, irrigation evaluations and simulations are presented, and irrigation schedules for optimal crop yield are proposed and evaluated via simulation. Author Keywords: Sprinkler irrigation; Irrigation performance; Water use; Farm management

In the first paper of this series, the Loma de Quinto Irrigation District (LQD) was characterised, and water use was assessed. In this work, the analysis of the LQD is completed with field irrigation evaluations, solid-set sprinkler irrigation simulations and irrigation scheduling for optimal crop yield. The results of the irrigation evaluations indicated that the average Christiansen coefficient of uniformity (CU) for solid-sets, centre-pivots and linear-moves was 68.0, 75.5, and 80.0%, respectively. In solid-sets CU was severely reduced by wind speed. However, in centre-pivots and linear-moves CU was higher in evaluations with wind speeds between 2 and 6 m s-1 than under calm conditions. The evaluation data set was used to validate a ballistic solid-set sprinkler irrigation simulation model. The performance variables used for model validation were CU and the potential application efficiency of the low quarter (PAElq). Both variables were adequately predicted in the range of the observed values. The model was used to extend the evaluation results to all the solid-set plots in the LQD. CU maps were produced for different wind speeds and operating pressures. These maps can be used to identify plots with low irrigation performance. The effect of irrigation scheduling on crop yield and net benefit was analysed using the CropWat simulation model. Simulations of the 1997 irrigation practices performed on a limited number of plots detected a 12% decrease in crop yield due to deficit irrigation and/or large irrigation intervals. The introduction of an optimal irrigation schedule (avoiding yield reductions) would imply increasing the alfalfa seasonal irrigation depth by 101 mm, and applying light, frequent irrigation events. Due to labour scarcity in the LQD, the implementation of the optimal schedule would require a high degree of irrigation automation, which is currently unavailable. Taking into consideration the value of the additional yield and the costs of the extra irrigation water depth and the automation devices, the resulting net benefit would be 50 ha-1. The purpose of this analysis of the LQD is to contribute to the diagnostic analysis phase of an incipient Management Improvement Program at the LQD. In order to complete this phase, an interdisciplinary committee will perform a study not just on irrigation but on a wide scope of irrigated agriculture in the LQD. Author Keywords: Sprinkler irrigation; Irrigation uniformity; Simulation model

Pags.- 4 Tabls.- 9 Figs. Available online 11 June 2014. The definitive version is available at: http://www.sciencedirect.com/science/journal/03783774, The simulation of center-pivot performance has been the subject of research efforts since the 1960s. Center-pivot models frequently use empirical equations relating pressure and sprinkler radial application pattern. Individual, stationary water application patterns are overlapped and the resulting water application is mapped in the field. Such models use constant tower angular velocity, neglecting the effect of tower alignment. In this work the discontinuous tower movement has been experimentally characterized and modelled, and a complete model has been developed by using a ballistic model of the center-pivot sprinklers considering nozzle diameter, operating pressure and wind speed. A detailed kinetic analysis of a four-tower commercial center-pivot was performed. Each tower was monitored using a high precision GPS, recording tower positions at high frequency. The experimental center-pivot was equipped with fixed spray plate sprinklers (FSPS). Five experimental center-pivot irrigation events were evaluated using catch-cans. The analysis of tower location data permitted to conclude that two key variables (linear speed and switching angle) showed normal distribution patterns. The center-pivot model was validated with catch-can data. Finally, the simulation tool was used to assess the effect of variable tower alignment quality, center-pivot travel speed and wind conditions on irrigation performance. Comparisons were performed in terms of radial, circular and total irrigation uniformity. Results indicate that the observed tower dynamics had no measurable effect on irrigation uniformity. Tower alignment quality started to be relevant when the switching angle lag was equal to or larger than 2°. In the conditions of this analysis, wind speed showed a clear effect on uniformity. As wind speed increased, uniformity first decreased and then increased. Further research is required to generalize these results to other center-pivot sizes and designs (sprinkler packages)., This research was funded by the Ministry of Economy and Competitiveness of the Government of Spain through grant AGL2010-21681-C03-01.

18 Pags., 1 Tabl., 3 Figs. The definitive version is available at: http://ascelibrary.org/toc/jidedh/140/3, Triangular weirs are commonly used to measure discharge in open channel flow, representing an inexpensive, reliable methodology to monitor water allocation. In this work, a low-speed photographic technique was used to characterize the upper and lower nappe profiles of flow over fully aerated triangular weirs. A total of 112 experiments were performed covering a range of weir vertex angles (from 30° to 90°), crest elevations (8 or 10 cm), and discharges (0.01–7.82 l s−1). The experimental nappe profiles were mathematically modeled and combined with elements of free-vortex theory to derive a predictive equation for the weir discharge coefficient. Comparisons were established between measured Cd, the proposed discharge coefficient equation, and discharge coefficient equations identified in the literature. The proposed equation predicts Cd with a mean estimation error (MEE) of 0.001, a root-mean square error (RMSE) of 0.004, and an index of agreement (IA) of 0.984. In the experimental conditions of this study, this performance slightly improves that of the equation proposed by Greve in 1932, and showed the same absolute value of MEE but lower values of RMSE and IA., This research was funded by the Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación of the Mexican Government (SAGARPA, Mexico) and the Secretaría del Campo of Zacatecas State Government (SECAMPO, Zacatecas). Thanks are also expressed to the Universidad Autónoma of Zacatecas, Mexico. Cruz Octavio Robles Rovelo received a scholarship from the Mexican Consejo Nacional de Ciencia y Tecnología (CONACYT).

A comparative study of two types of spray sprinklers was performed. Rotating spray plate sprinklers (RSPSs) and fixed spray plate sprinklers (FSPSs) were evaluated individually in open field conditions. The water distribution, wind drift, and evaporation losses during the evaluations were measured under low, medium, and high wind speed conditions with three nozzle diameters and two nozzle heights above the soil surface. Individual spray sprinkler water distributions were mathematically overlapped to simulate the water distribution resulting from sprinkler machines. The water distribution of the RSPS had a conical shape, whereas the FSPS concentrated the water application in a circular crown. The uniformity coefficient of the simulated water application in sprinkler machines fitted with RSPSs or FSPSs was >93% in all cases. However, the RSPS could attain a higher uniformity coefficient at higher spacing along the lateral. For the nozzle diameters of 6.7 and 7.9 mm, the wetted width produced by the RSPS was larger than that of the FSPS. Also, the peak instantaneous precipitation rate of the RSPS was smaller than that of the FSPS., This work was sponsored by the Superior Council of Research and Development (CONSI&D) of Aragón, Spain, and by the Spanish-German cooperation program ‘‘Water and Energy Conservation in Irrigated Systems’’ sponsored by the respective Ministries of Agriculture.

7 Pag., 3 Tabl., 5 Fig., Success in breeding crops for yield and other quantitative traits depends on the use of convenient methods to accurately evaluate genotypes under field conditions. We report the evaluation of a drip-injection irrigation system (DIS) for assessing the salt tolerance of barley genotypes. Ten barley cultivars were randomized within each of nine salinities imposed by a DIS in an experiment with two replications. Grain yields were regressed against soil salinity (ECe) using a sigmoidal growth response model to obtain the statistics Ym, ECe50, and p. The data fitted the model well; the average correlation coefficient was 0.89 (P < 0.001) when the observations for each cultivar in both replications were pooled, and the average SEs were

A model of solute transport in overland flow is developed and applied to the simulation of surface fertigation. Water flow is simulated using the depth-averaged, 1D shallow water equations. Solute flow is represented by an advection-diffusion model. The resulting set of three partial differential equations is sequentially solved at each time step. First, water flow is computed using the explicit two-step McCormack method. Based on the obtained velocity field, solute transport is explicitly determined from the advection-diffusion equation using the operator split technique. Four field experiments involving fertigation events on an impervious free-draining border were performed to validate the proposed model and to obtain estimates of Kx, the longitudinal dispersion coefficient. A value of Kx = 0.075 m2 s-1 satisfactorily reproduces the field experiments. The model is also applied to the simulation of a fertigation event on a pervious border. A sensitivity analysis is performed to assess the dependence of fertilizer distribution uniformity on the value of Kx. Finally, the proposed model is compared with a previous model based on pure advection., The writers would like to express their gratitude to the CONSI+D of the Government of Aragón, Spain. Their Grant PCA1094 made this research possible. Thanks are also due to the INIA of the government of Spain for granting a scholarship to N. Zapata.

Surface irrigation simulation models have seldom been used in engineering practise, and district modernisation is not an exception. Surface irrigation evaluations were performed in the Almudevar irrigation district to obtain the parameters required for surface irrigation modelling. The total district irrigated area was divided into 92 design units, for which a characteristic blocked-end border was defined. Simulation was used to establish the current irrigation performance in each design unit, and district performance contour maps were built. Irrigation performance was characterised using potential application efficiency, with an average of 54%, and irrigation time, averaging 6 h ha−1. Simulated potential application efficiency of the low quarter was similar to the seasonal irrigation performance index (an estimate of irrigation efficiency) presented in the companion paper. A set of seven modernisation scenarios was defined. Two strategies were identified to improve the potential application efficiency in the scenarios: increase the irrigation discharge into the current blocked-end borders and/or substitute the current system with a solid set sprinkler irrigation system. The performance of each scenario was estimated using irrigation models to determine efficiency, water conservation and irrigation time. The modernisation investment costs were estimated and compared to the performance of each scenario. The best results (potential application efficiency of 77%, reduced water allocation by 14.4 106 m3 year−1) were obtained by a combination of blocked-end irrigation with a discharge of 200 l s−1 and sprinkler irrigation in the areas where surface irrigation efficiency could not attain 50%. The investment cost for this scenario was 3932 Euro ha−1. More expensive scenarios did not guarantee better performance.

The analysis of water management in irrigated districts is highly relevant. The present work highlights the principal irrigation management problems of the irrigation district of Almudevar, a representative surface irrigation district located in the northeast of Spain. The predominant irrigation system is blocked-end borders. The study included three phases: (1) assessment of crop water requirements of the main crops of the study area; (2) characterisation of soil depth and soil water retention; and (3) analysis of the current irrigation practices based on the study of the 1994 water records of the district. The following irrigation management problems were identified: (1) the mean volume of water billed to the farmers was 43% higher than the net irrigation requirements; (2) the volume of water billed to the farmers were inversely related to the farm size; (3) few, widely spaced, large irrigation events; (4) large delay time in water delivery; and (5) in selected crops and/or areas, water billing was lower than the net irrigation requirements, indicating the presence of marginal areas or heavily subsidised crops. This research could be applied in other areas of traditional surface irrigation systems. The goal of this methodology is to diagnose the actual level of water management and to provide data for the modernisation of the irrigation district. In a companion paper, a decision support system for the modernisation of the district is presented.

15 Pags.- 5 Figs. Esta revista se publica bajo una licencia de Creative Commons Reconocimiento-NoComercial-SinObraDerivada 4.0 Internacional., [ES]El regadío ha sido, sigue siendo y será uno de los pilares básicos para el desarrollo y mantenimiento de la población humana. Su evolución pasada ha ido al unísono del avance de los conocimientos en materias propias de agronomía e ingeniería del agua y de la tecnología (desarrollo de materiales plásticos, elementos electrónicos…) llegando a un estado actual en el que todavía están por resolver muchos interrogantes que quedan como retos para el futuro. Cabe destacar el fuerte impulso del regadío en Brasil en la última década. Aprovechando el relanzamiento de la revista Ingeniería del Agua se presenta una visión del regadío, dentro del espacio limitado de este artículo, que incluye algunas de las líneas de investigación actuales, algunas novedosas como la relacionada con el movimiento del agua en el sistema suelo-planta de las especies mediterráneas y sus consecuencias en el uso del agua, con el fin de motivar la publicación en Ingeniería del Agua de artículos relacionados con la variada temática que integra el estudio del Regadío en las comunidades de lengua española y portuguesa., [EN] Irrigation not only has been a key factor for the development and maintenance of human societies but it still plays this role now and it is foreseen that in the future as well. Its evolution has been constrained to the advance in knowledge on matters regarding Agronomy and Water Engineering and in technology however, many challenges deserve further research. It is worth to note that Brazil has strongly promoted irrigation in the last decade. Within the limited extension of this article, some current topics in irrigation, some of them are innovative such us the research line studying water flow in soil-plant in Mediterranean plants and its consequences on water use,. and future challenges are presented with the purpose of stimulate publication of Irrigation papers in the journal “Ingeniería del Agua” among Portuguese and Spanish language communities.

31 Pags., 2 Tabls., 10 Figs. The definitive version is available at: http://ascelibrary.org/toc/jidedh/139/7, Ballistic simulation has been successfully applied to impact sprinklers. However, ballistic simulation of center pivot sprinkler irrigation has been limited by the difficulty in estimating the initial drop velocity vector in fixed and rotating spray plate sprinklers. Initial velocity is severely affected by the impact of the jet on the sprinkler deflecting plate (or plates). In this work, experimental techniques based on drop photography have been used to obtain the droplet velocity and angle in the vicinity of a fixed spray plate sprinkler by using three different nozzle diameters. Furthermore, simulation techniques based on the inverse solution of drop trajectory were combined to determine the initial velocity vector and energy loss at the spray. Our analysis suggests that the ballistic model can be used to simulate drop inverse trajectory in these sprinklers, although the ballistic model can benefit from 5 to 10% effective drag-force screening. The ratio of initial drop velocity to jet velocity was between 0.67 and 0.82, whereas the kinetic energy losses in the spray sprinklers amounted to 33–55%., This research was funded by the National Research, Development and Innovation Plan of the Government of Spain (Plan Nacional de I+D+I) through grant AGL2010-21681-C03-01, and by the Special Intramural Grant 200940I041 of CSIC (funding G. S´anchez Burillo). R. Delirhasannia received a scholarship from the Ministry of Science, Research and Technology 301 of Iran to perform a scientific stay at the Aula Dei Experimental Station of CSIC, Zaragoza, Spain.

18 Pags., 6 Tabls., 7 Figs. Available online at www.inia.es/sjar, Fruit production development is resulting in large commercial orchards with improved water management standards. While the agronomic and economic benefits of regulated deficit irrigation (RDI) have long been established, the local variability in soils and climate and the irrigation system design limits its practical applications. This paper uses a case study approach (a 225 ha stone fruit orchard) to unveil limitations derived from environmental spatial variability and irrigation performance. The spatial variability of soil physical parameters and meteorology in the orchard was characterized, and its implication on crop water requirements was established. Irrigation depths applied during 2004- 2009 were analysed and compared with crop water requirements under standard and RDI strategies. Plant water status was also measured during two irrigation seasons using stem water potential measurements. On-farm wind speed variability amounted to 55%, representing differences of 17% in reference evapotranspiration. During the study seasons, irrigation scheduling evolved towards deficit irrigation; however, the specific traits of RDI in stone fruits were not implemented. RDI implementation was limited by: 1) poor correspondence between environmental variability and irrigation system design; 2) insufficient information on RDI crop water requirements and its on-farm spatial variability within the farm; and 3) low control of the water distribution network, This research was funded by the Plan Nacional de I+D+i of the Government of Spain through grant RIDECO-CONSOLIDER CSD2006-00067 and by CSIC through the grant PIE 2007-2009.

48 Pags., 3 Tabls., 11 Figs. The definitive version is available at: http://link.springer.com/journal/271, Increasing water and fertilizer productivity stands as a relevant challenge for sustainable agriculture. Alternate furrow irrigation and surface fertigation have long been identified as water and fertilizer conserving techniques in agricultural lands. The objective of this study was to simulate water flow and fertilizer transport in the soil surface and in the soil profile for variable and fixed alternate furrow fertigation and for conventional furrow fertigation. An experimental data set was used to calibrate and validate two simulation models: a 1D surface fertigation model and the 2D subsurface water and solute transfer model HYDRUS-2D. Both models were combined to simulate the fertigation process in furrow irrigation. The surface fertigation model could successfully simulate runoff discharge and nitrate concentration for all irrigation treatments. Six soil hydraulic and solute transport parameters were inversely estimated using the Levenberg–Marquardt optimization technique. The outcome of this process calibrated HYDRUS-2D to the observed field data. HYDRUS-2D was run in validation mode, simulating water content and nitrate concentration in the soil profiles of the wet furrows, ridges and dry furrows at the upstream, middle and downstream parts of the experimental field. This model produced adequate agreement between measured and predicted soil water content and nitrate concentration. The combined model stands as a valuable tool to better design and manage fertigation in alternate and conventional furrow irrigation., This research was funded by The Center of Excellence for Evaluation and Rehabilitation of Irrigation and Drainage Networks of the University of Tehran.

This chapter presents a discussion of a set of technological actions aimed at living with drought in the irrigated agricultural region of the Ebro Basin in Spain. The basin faces recurrent drought episodes that have led farmers to take action on the structural and water management aspects of water conservation. Structural works have taken the form of large irrigation modernization plans, affecting about one-fourth of the currently irrigated land. Modernization typically implies the construction of collective, remote-controlled, pressurized irrigation networks and the installation of on-farm sprinkler/drip irrigation systems. The impacts of these modernization projects on the Ebro Basin hydrology and on the economy and productivity of irrigated agriculture are discussed. In parallel, actions have been set up to improve water management, mostly at the water-user association (WUA) level. The cooperative design, elaboration, and dissemination of a database software supporting daily water management operations in WUAs is presented, and the utilities for drought management are discussed. Finally, a plan for action benefiting from improvements on both structures and water management capacities is presented. This new action comprises automated irrigation scheduling and operation, and is based on a combination of remotely controlled networks, WUA management and meteorological databases, and irrigation engineering tools. The proposed action has already undergone significant research and could result in the generalization of scientific irrigation scheduling and in the complete automation of irrigation operation. Technology can support farmers in their efforts to adapt to drought conditions and still obtain sustainable profits.

16 Pags., 4 Tabls., 11 Figs., Alternate furrow irrigation and surface fertigation have been known as techniques to control water and fertilizer losses. The main goal of this field study was to characterize the combined effect of these techniques on water and nitrate losses and on soil water and nitrate concentration. Two types of alternate furrow irrigation, i.e., variable alternate furrow irrigation (AFI) and fixed alternate furrow irrigation (FFI), as well as conventional furrow irrigation (CFI) were considered in the experiments. Results evidenced higher infiltration at irrigated furrows under AFI and FFI as compared to CFI. Increased lateral water movement under alternate irrigation resulted in lower water and nitrate losses via runoff and deep percolation. Water application efficiency for the CFI, FFI and AFI strategies amounted to 61.3%, 71.8% and 77.0% in the first fertigation and 36.4%, 58.8% and 60.7% in the second fertigation, respectively. Nitrate runoff for the CFI, FFI and AFI strategies amounted to 32.4%, 31.2% and 25.7% in the first fertigation and 44.3%, 35.1% and 32.7% in the second fertigation, respectively. Soil water content and nitrate concentration at the upstream part of the experimental field were larger than at the middle and downstream parts for all three irrigation regimes. Overall, alternate furrow fertigation, particularly AFI, stands as a simple and practical management practice for water and fertilizer conservation in agricultural fields., This research was funded by The Center of Excellence for Evaluation and Rehabilitation of Irrigation and Drainage Networks in the University of Tehran.