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In recent years, the use of fertigation technology with center pivot irrigation systems has increased rapidly in the North China Plain (NCP). The combined effects of water and nitrogen application uniformity on the grain yield, water use efficiency (WUE) and nitrogen use efficiency (NUE) have become a research hotspot. In this study, a two-year field experiment was conducted during the winter wheat growing season in 2016–2018 to evaluate the water application uniformity of a center pivot with two low pressure sprinklers (the R3000 sprinklers were installed in the first span, the corresponding treatment was RS; the D3000 sprinklers were installed in the second span, the corresponding treatment was DS) and a P85A impact sprinkler as the end gun (the corresponding treatment was EG), and to analyze its effects on grain yield, WUE and NUE. The results showed that the water application uniformity coefficients of R3000, D3000 and P85A along the radial direction of the pivot (CUH) were 87.5, 79.5 and 65%, respectively. While the uniformity coefficients along the traveling direction of the pivot (CUC) were all higher than 85%. The effects of water application uniformity of the R3000 and D3000 sprinklers on grain yield were not significant (P>0.05); however, the average grain yield of EG was significantly lower (P

Sprinkler irrigation systems can be managed and designed by only conducting an individual sprinkler test in no wind conditions. The present work was conducted to study the effect of different operating pressures and riser heights to determine optimum operating conditions that achieve high application efficiency and wheat production in impact sprinkler system. The coefficient of uniformity (CU,%) was evaluated within the operating pressure range from 100 to 350 kPa, riser heights 1.0, 1.5 and 2.0 m, overlapped from 100 to 20% under square and triangular layouts sprinkler. It was concluded that the operating conditions that achieved high CU was operating pressure of 250 kPa and 1.5 m riser height for impact sprinkler. Information from individual sprinkler test was established to carry out the corresponding overlapping ranged from 20 to 100% in square and triangular layouts sprinkler. Optimal spacing between sprinklers was found to be as 50 to 70% from diameter of throw in square layout. It was found in range of 50 to 80% from diameter of throw in triangular layout sprinkler. The wheat yield was highly affected by water requirements (100, 80 and 60% ETc). The results showed that the average values of total grain and straw yield/fed, increased with increasing ETc from 60 to 100%. The highest yield was achieved with 100% ETc, while, WUE with 80% ETc was the highest value. It could be recommended to apply irrigation water to 100% ETc that has the highest yield of wheat under operating pressure of 250 kPa with good CU for impact sprinkler. On the other hand, adding 80% ETc applied gave the highest values was preferred when the priority to save on the applied water and increase water productivity. Also, layout spacing ≥ 50% from diameter of throw was recommended.

A set of nozzle and water dispersion devices were designed to obtain a desirable jet breakup and save water from an impact sprinkler (IS) at low pressure conditions. Comparative performance indicators were obtained for the commercial LP and IS sprinkler heads. Results show that under the same working conditions, the IS produced a large spray range and the water distribution in the middle of the spray range (R) was better than the LP. The best simulated uniformity from the IS was obtained for the combined spacing factor of 1.4*R and the combined uniformity was 4% larger than the LP. Considering the middle position of the spray range, the number and diameter of the droplets from the IS were larger than the droplets from the LP. However, in the end position of the spray range, the droplet diameters from the IS were quite smaller than the LP. Velocities from IS ranged between 0.2 and 6.4 m/s, while that from LP sprinkler were slightly higher ranging from 0.15 to 7.7 m/s at 150 kPa. Overall, introduction of the fixed dispersion device with a pointed tip profile combined with the 6 mm nozzle offered some advantages for the IS over the LP sprinkler at low-pressure conditions. Keywords: Dispersion device, Droplet distribution, Impact sprinkler, Low pressure sprinkler, Nozzle, Spray range, Uniformity.

An impact sprinkler with a newly designed nozzle-dispersion device and R33 sprinkler were introduced in this study. Comparative experiments and analyses on uniformity patterns of impinging water jet from both sprinklers were investigated by using high-speed photographic technique to visualize the spray. A mathematical model of the spray was developed and applied in MatLab to determine the spray angles at different axial distances. Results showed that the impact sprinkler with the nozzledispersion device combination gave the largest spray range of 12.6% larger than the R33 sprinkler. Combined effect of the nozzle-dispersion device for the impact sprinkler had a strong effect on the spray angle which increased with increasing pressure. Spray characteristics for the impact sprinkler were similar to those produced by the R33 sprinkler. The number of droplets increased with increasing spray angle due to early breakup of the jet, which is beneficial for greater water dispersion and uniformity. It was found that a low working pressure of 150 kPa leads to lower degree of nonuniformities for the sprinklers, and the variation coefficient were less than 10%. Obtained mathematical models of the changes in the variation coefficient was dependent upon working pressure and can be a good basis for easy management of the parameters necessary for the uniform spray distribution. Hence, the impact sprinkler with the nozzle-dispersion device can offer superior advantage of a larger spray range for better overlap and disperse more droplets for better Uniformity under low pressure conditions.

Water is limited resource. This is considered to be one of the main challenges for future water policy. Saving water and energy is a requirement to ensure the viability of pressurized irrigation systems. Designing and optimizing sprinkler irrigation systems are mainly based on achieving appropriate hydraulic performance. Spray nozzles being very often a critical component in determining the final quality of the product or the sprinkler irrigation efficiency process. The engineering design factors of sprinkler affect sprinkler system performance. So, this study focuses on some engineering design factors (three different nozzle characteristics (1, 2 and 3) and operating pressures from 150 to 250 kPa), comparing with designed nozzle (No 4) to improve brass impact sprinkler performance. This study sited on Giza region at National Laboratory for testing the components of irrigation networks and field drainage, Agricultural Engineering Research Institute AEnRI, Agricultural Research Center ARC. The result of Christiansen uniformity coefficient CU indicated that designed nozzle No 4 achieving good performance according to American society of Agricultural and Biological Engineers ASABE 2001 starting with operating pressure 150 kPa 74.05 % while nozzle No 3 starting with 175 kPa achieved 75.23 %. Also it was found that nozzle No 4 increasing flow rate by 43.48 %, precipitation rate by 19.92 %, rotation speed by 24.96 %, decreasing coverage radius by 28.38 % and the jet breaks up sufficiently to achieve an adequate water distribution pattern and obtained good droplet size comparing with nozzle No 3. It was found that sprinkler layouts 9m Х 9m overlapping achieved acceptable uniformity at operating pressure 150 kPa. Also the result indicated that nozzle No 4 saved operating time ratio by 26.87 % and decreased over minimum application targeted irrigation depth by 66.7 % at the same overlapping distances and at the same operating pressure 150 kPa.

The aim of this study is to improve the water distribution uniformity of a vertical impact sprinkler and explore the design method of the drive spoon blades. The width of straight blades (h1), the width of curved blades (h2) and number of blades (s) were chosen as the experiential variables. The suitable ranges of three variables for response surface method were determined initially by one-factor experimental design method, and 17 different drive spoons were designed according to response surface methodology. The results showed that in the one-factor experimental condition, the CU (Christiansen’s uniformity coefficient) values first increased and decreased slightly when h1 exceeded 3 mm with the increase of h1 within the variation range of the experimental factor. The CU values firstly increased and then decreased with the increase of h2. The CU values decreased rapidly when s was less than 3 or greater than 6. The relationship between CU values and h1, h2 and s was established using response surface methodology. The p-values for h1, h2 and s were 0.0359, 0.0092, 0.0212, and all of the selected factors were significant on CU. The order of parameters affecting CU were h2, h1 and s. The ideal parameters for the drive spoon blades were h1 = 6 mm, h2 = 4 mm, and s = 3. CU was greatly improved after the optimization of structure for the drive spoon blades, which increased to 87.96% from 73.12%. After optimization, the application rates within 1 to 5 m were improved and increased from 10% to 15% with an average of 10.7% under different operating pressures. The maximum application rates decreased from 9.3, 9.3, 9.4 and 8.4 mm·h−1 to 8.5, 8.4, 8.5 and 7.9 mm·h−1 with operating pressures of 300, 400, 500 and 600 kPa, respectively. The maximum application rates in the overlap area were decreased from 18, 16, 16 and 15 mm·h−1 to 16, 14, 14 and 12 mm·h−1 with operating pressures of 300, 400, 500 and 600 kPa, respectively.

A water jet aeration method was used to address the problem of high water application rates for rotating impact sprinklers operating at low pressures at the distal end of the wetted radius ...

HighlightsThe hydraulic performance of the impact sprinkler with circular and non-circular nozzles were measured.A High-Speed Photography (HSP) technique was employed to extract the jet breakup process of the impact sprinkler.Two index equations of jet characteristic lengths and equivalent diameters of non-circular nozzles were fitted. Abstract. An experiment was carried out to investigate the hydraulic performance of an impact sprinkler by using circular and non-circular nozzles. A High-Speed Photography (HSP) technique was employed to extract the breakup process and flow behavior of low-intermediate pressure water jets issued from the different types of orifices. These orifices were selected by the principle of equal flowrate with the same pressure. Moreover, two characteristic lengths: the jet breakup length and the initial amplitude of surface wave were measured. It was found that the sprinkler with circular nozzles produced the largest radius of throw followed by square nozzles and regular triangular nozzles when the cone angle of nozzle and pressure were unchanged, while the sprinkler with regular triangular nozzle had the best variation trend of water distribution and combination uniformity coefficient. Regular triangular jets exhibited a higher degree in breakup and the shortest breakup length compared with the square jets and the circular jets. The initial amplitudes of surface waves of regular triangular jets were larger than the square jets and the circular jets with the same cone angle. Two index equations of jet characteristic lengths and equivalent diameters of both circular and non-circular orifices were fitted with a relative error of less than 10%, which means the fitting formulas were accurate. Keywords: Breakup length, Fitting formula, Hydraulic performance, Initial amplitude, Non-circular jets.

Sodic soils are characterized by high exchangeable sodium on exchange sites, soil pH greater than 8.5, relatively low electrical conductivity, low infiltration rate and dispersed clay. These characteristics restrict the capacity of soil to absorb water, resulting in poor infiltration. Evidently, these soils require application of irrigation water at shorter intervals for crop production. Thus, irrigation strategy for sodic soils differs from that of normal soils. An experiment to determine the suitable irrigation strategy along with methods of application namely: surface (farmer’s practice), sprinkler (double nozzle impact sprinkler), and low-energy water application device (LEWA) were initiated in the year 2012 for rice crop. Irrigation depths of 6 cm in case of surface method and 4 cm in case of sprinkler and LEWA methods were applied at each irrigation event. The irrigation events for rice were scheduled at 2-DAD (days after the disappearance of the ponded water), 3-DAD, and 4-DAD through surface method, and at daily, 1- and 2-day intervals (after initial ponding disappeared) by sprinkler and LEWA methods. Sprinkler and LEWA methods resulted in highest rice yield of 4.4 t ha−1 in irrigated plots at the 2-day interval which was at par with the highest yielding surface-irrigated plot scheduled at 2-DAD. At the same time, irrigation strategy of 2-day interval through sprinkler and LEWA methods registered water saving to the extent of 30–40% over 2-DAD under surface irrigation method. Results revealed that there could be substantial saving of water and energy (electricity and diesel) through the use of sprinkling devices for irrigating rice under sodic soil environments.

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 world is increasingly experiencing water scarcity due to the impact of climate change, a phenomenon that is affecting agricultural production, particularly in tropical regions. An effective response system is required to adapt and reduce the impact on agricultural production. There have been calls on the role agriculture can play to reduce the impact without compromising food security. Hence, the present article discusses some of the major difficulties in water-smart sprinkler irrigation to adapt to the impact of climate change on agricultural production. In order to meet investment cost with water-smart sprinkler irrigation, the fixed water dispersion device for an impact sprinkler needs to be optimized to improve its performance under low pressure conditions. This is necessary to produce the desirable droplets sizes for minimising evaporation losses and distortion by wind, whilst maintaining the large distance of throw. Further research should be backed by strong institutional support towards a wide-scale adoption of water-smart sprinkler irrigation technologies. This could be of significant benefit to better water management in the artificially drained catchments and lessen the impact of climate change on agricultural production.

The main objective of the present study is to evaluate two types of sprinklers (impact sprinkler and rotating sprinkler), impact sprinkler (average nominal discharge from 780 to 1660 l/h at operating pressure from 100 to 400 kPa) and rotating sprinkler (average nominal discharge from 360 to 730 l/h at operating pressure from 50 to 350 kPa) to determine optimum operating conditions that achieve high application uniformity. The coefficient of uniformity (CU) and distribution uniformity (DU) were evaluated under different levels of operating pressure and constant riser height of 1.0 m. It was concluded that the operating conditions that achieved high coefficient of uniformity and distribution uniformity was operating pressure of 200 kPa for impact sprinkler. The results showed that the highest values of CU and DU were 90.55 % and 68.10 % for impact sprinkler respectively while for rotating sprinkler with combination of trajectory angles (20o, 25o), the corresponding values of CU and DU were 85.60 % and 60.50 %, respectively. Also, to achieve high percentage of overlap simulation model was used, it appeared that the spacing between sprinklers should be higher than or equal to 50 % of wetted diameter to avoid water lose and minimize irrigation system cost.

Impact sprinkler (20PY2 IS) outlet is a single-phase water flow, and the aeration impact sprinkler (20PY2 AIS) outlet is gas-liquid two-phase flow. The jet dispersing principle of AIS is somewhat different from conventional sprinklers and has advantages and the ability to working well at the low-pressure condition. The experimental study on the droplet size distribution of IS and AIS was carried out by the volume-weighted method to analyze the mean diameter (Dv), median diameter(D50), water droplets frequency distribution, and the cumulative frequency at different distances from sprinklers. Similarly, the velocity of the drop was measured by Laser Precipitation Monitor (LPM) and statically analyzed by using a number-weighted method. The results showed that both the drop diameters Dv and D50 increased with the distance from the sprinkler nozzle but decreased with an increase in the working pressure. Similarly, droplet frequency distribution at a diameter

A comparative study of an outside signal sprinkler (OS), a fluidic sprinkler (FS), and an impact sprinkler (IS) was carried out. The OS, FS, and IS were evaluated individually under indoor experimental conditions. Water distribution evaluations were measured under four operating pressures at a 1.5-m nozzle height (above the ground). Approximately 36 individual trials were performed. The results show that the discharge coefficient of the OS and FS was slightly larger than that of the IS. The water distribution profiles of the OS, FS, and IS were parabola-shaped, ellipse-shaped, and doughnut-shaped, respectively. The wetted radius for the OS was similar to the wetted radius of the FS and was 8.7–12 % less than the IS. An accurate and simple empirical equation for the wetted radius of OS and FS is reported. Additionally, equations of water application rate, with regard to distance from the sprinklers, are given. The average coefficients of determination for the OS, FS, and IS were 91.8, 89.2, and 79.1 %, respectively. Individual spray sprinkler water distributions were mathematically overlapped to calculate the combined uniformity coefficient (CU). Maximal combined CUs of 80.88, 80.92, and 78.12 % were found for the OS, FS, and IS, respectively. Both the OS and FS were found to have greater CU values than the IS, which indicates that the OS and FS provided a better water distribution pattern than the IS at low pressure.

A field trial in Salinas Valley, California, was conducted during July 2011 to quantify the microbial load that transfers from wildlife feces onto nearby lettuce during foliar irrigation. Romaine lettuce was grown using standard commercial practices and irrigated using an impact sprinkler design. Five grams of rabbit feces was spiked with 1.29 × 10(8) CFU of Escherichia coli O157:H7 and placed - 3, - 2, and - 1 days and immediately before a 2-h irrigation event. Immediately after irrigation, 168 heads of lettuce ranging from ca. 23 to 69 cm (from 9 to 27 in.) from the fecal deposits were collected, and the concentration of E. coli O157:H7 was determined. Thirty-eight percent of the collected lettuce heads had detectable E. coli O157:H7, ranging from 1 MPN to 2.30 × 10(5) MPN per head and a mean concentration of 7.37 × 10(3) MPN per head. Based on this weighted arithmetic mean concentration of 7.37 × 10(3) MPN of bacteria per positive head, only 0.00573% of the original 5 g of scat with its mean load of 1.29 × 10(8) CFU was transferred to the positive heads of lettuce. Bacterial contamination was limited to the outer leaves of lettuce. In addition, factors associated with the transfer of E. coli O157:H7 from scat to lettuce were distance between the scat and lettuce, age of scat before irrigation, and mean distance between scat and the irrigation sprinkler heads. This study quantified the transfer coefficient between scat and adjacent heads of lettuce as a function of irrigation. The data can be used to populate a quantitative produce risk assessment model for E. coli O157:H7 in romaine lettuce to inform risk management and food safety policies.

Single leg tests were conducted to determine performance of two different sprinkler that can be used in impact sprinkler irrigation systems design operating at 100, 200 and 300 kPa. The different two sprinklers HS2803 and Gardena impulse sprinkler were tested for coefficient of uniformity (CU), soil moisture content (MC) and EC (electrical conductivity) at three different pressure points for two different microclimate screen greenhouse and no tillage field conditions. As well as the experimental carried out at three different riser height of the sprinkler 0.6 m , 1.0 m and 1.2 m. Radial leg tests have been previously performed to find the water distribution pattern. Afterwards both outdoor single-sprinkler irrigation tests have been also performed to know the water distribution pattern distorted by microclimate conditions spatially the wind action. Results show that the main factors to be controlled are: the wind speed, the sprinkler type and the riser height. Results showed that higher Coefficients of Uniformity (CU) are attained with HS2803 three armed sprinkler than with a single impulse sprinkler under low wind speeds in screen greenhouse. As well as, the maximum values of coefficient uniformity CU percent under screen greenhouse conditions were 93.7% and 89.5% for HS2803 and Gardena impulse sprinkler at 300 kPa respectively. The soil moisture contents at 300 kPa operating pressure and 0.6 riser height under field conditions were 39.6 % compared to 26.7 for HS2803 sprinkler and Gardena impulse sprinkler respectively. The soil conductivity (EC) at 300 kPa operating pressure under field conditions were 2.1 cmSm-1, 2.4 cmSm-1 and 2.6 cmSm-1 compared to 3.9 cmSm-1, 4.1 cmSm-1 and 4.4 cmSm-1 for HS2803 sprinkler and Gardena impulse sprinkler respectively.

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.

37 Pags., 6 Figs., 3 Tabls. The definitive version is available at: http://www.sciencedirect.com/science/journal/15375110, The radial water distribution and irrigation performance of an agricultural sprinkler with plastic nozzles were analysed. Twenty-six tests with an isolated sprinkler corresponding to different combinations of three working pressure (p, 200, 300 and 400kPa) and three nozzle diameters of the main nozzle (4.0, 4.5 and 5.0mm) were performed to evaluate the radial water distribution curves, All the tests were performed under calm wind (≤1ms-1) under open air conditions. Fifty tests corresponding to six combinations of nozzle diameter and pressure with the same sprinkler model were performed under a wide range of meteorological conditions in a rectangular solid-set system at 18m×18m sprinkler spacing to evaluate the Christiansen's Uniformity Coefficient (CUC) and wind drift and evaporation losses (WDEL). The resulting radial water distribution curves were compared with those from impact sprinklers with brass nozzles. Sprinkler model had an important effect on the radial water distribution, even under similar operational conditions, and these differences were shown in the first 2.5-6m from the sprinkler. The CUC and WDEL of a solid-set sprinkler system were compared with simulated values from the >Ador-Sprinkler> model. The results of this analysis showed that the type of sprinkler had a moderate influence on sprinkler irrigation uniformity. The analysis presented in this study may serve to develop a decision tool to choose the most suitable combinations of sprinkler model, nozzle diameter and working pressure to optimise the uniformity and efficiency of sprinkler irrigation., This research was funded by the MCINN of the Government of Spain through grants AGL2007-66716-C03-01/02, AGL2010-21681-C03-01/03; the European Commission through grant QUALIWATER (INCO-CT-2005-015031) and by the FPI-MICINN PhD grants programme.

To improve the fire suppressing efficiency and reliability of the sprinkler systems, in this paper we analysis and discuss a problem about sprinklers arrangement. Use the water distribution curve of ZST-15 and the MATLAB to accomplish a 3D surface fitting among radius of protection, working pressure and mounting height as well as get a function expression about them. After that, aiming at the problems happened in engineering practice, we propose a method of determine the sprinklers arrangement distance and their mounting height, in addition give suggestions about choosing fire pools and work out the flow rate of sprinkler systems through calculation as well.

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.

In this article, a new type of variable-rate complete fluidic sprinkler is proposed. This sprinkler system was designed to achieve a variable wetted radius of the spray by moving two inserts relative to each other to change the inlet cross-sectional area. To determine the design method, the relationship between the pressure, the inlet cross-sectional area, and the rotating angle were analyzed by MATLAB for a square spray, the working pressure of the variable-rate sprinkler system spray in an irregular boundary area was calculated, and the relationship of the pressure values was obtained. The experiments were carried out using an automatic measurement system, and the wetted radius deviation, uniformity coefficient, wetted radius reduction coefficient and shape coefficient were calculated. The results showed that the experimental square wetted radius agreed well with the theoretical curves, and the deviation was 4.22%. The irrigation water distribution data were uniform at every spraying angle. The uniformity coefficient of the complete fluidic sprinkler system was 72.2%, which is larger than an impact sprinkler system. The decreased coefficient was 21.48%, and the shape coefficient was 91.7%. As a result, a square spray pattern was achieved using the variable-rate complete fluidic sprinkler system.

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.

Soil characteristics' degradation had been considered as one of the most important problems that face the agricultural development processes under arid and semi-arid conditions due to non-suitability of the applied technologies and techniques, attributed to management considerations. Consequently, higher crop yield and quality reduction had been occurred due to the degradation of the plant healthy media (soil). Therefore, the goal of this investigation was to monitor the change detection of some soil physical and hydrophysical characteristics under sprinkler irrigated agriculture. However, the terminal objectives were to evaluate and monitor some soil characteristics changes (soil bulk density, hydraulic conductivity and soil penetration resistance) under different mode of action of sprinkler types (rotating and impact sprinkler) and corresponding nozzle sizes (small and large sizes). Hereby, field experiments were carried out for two seasons (2006 and 2007) in the Desert Experimental Farm of Faculty of Agriculture, AinShamsUniversity which is located at El-Bustan region, Behaira Governorate. Results revealed that soil characteristics were highly affected with the sprinkler mode of action and corresponding nozzle sizes. However, a power function proportion of soil penetration resistance with respect to applied rotating and impact sprinkler types and corresponding small and large nozzle sizes, had been observed and analyzed. Therefore, data analysis speculated that, selection of the appropriate sprinkler types under diverse field conditions and situations such as: crop type and design criteria of sprinkler irrigation systems, have to be considered for good agricultural development processes under Egyptian newly reclaimed regions.

An integral 3D numerical model based on the structural characteristics of the impact sprinkler was constructed to simulate the relationship between flow rates and inlet pressures as well as the flow field distribution by computational fluid dynamics (CFD). A commonly used PY140 sprinkler in China with three different flow straighteners in lengths of 80, 140 mm and 200 mm respectively and without flow straightener was investigated under inlet pressures ranging from 300 kPa to 500 kPa numerically and experimentally. The simulation results obtained revealed that the predicted relationship of flow rates and inlet pressures was in good agreement with the measurements. Fixing a proper flow straightener can effectively improve the turbulent flow state inside the sprinkler and lead to a more uniform velocity at the nozzle outlet. The sprinkler with a flow straightener resulted in a larger pressure loss within the internal flow than the sprinkler without flow straightener. A longer flow straightener caused a smaller turbulent kinetic energy at the nozzle outlet, which indicated that the length of flow straightener had no significant effect on the flow rate. As well, it was found that reversed flow happened near the nozzle outlet with a diffused angle of 90° could be observed clearly. The decrease of the diffused angle from 90° to 60° can supply a larger flow rate, which was verified by an experiment.