Sprinkler Irrigation Uniformity Research Articles

Evaluating soil water movement and soil water content uniformity under sprinkler irrigation with different soil texture and irrigation uniformity using numerical simulation

Water movement and its distribution uniformity in the soil are essential for the design of sprinkler irrigation systems. They are both crucial factors influencing nutrient migration and the productivity of crops. In this study, a new numerical simulation method was proposed to investigate the soil water movement in sprinkler irrigation under nonuniform infiltration boundary conditions using COMSOL software. Besides, two soil tank experiments were conducted to test the reliability of the simulation model. Finally, the model was applied to evaluate the effects of sprinkler irrigation uniformity, soil texture, and initial soil water content on soil wetting patterns and soil water content uniformity. The results showed that the COMSOL-2D predictions of the vertical wetting fronts were in good agreement with the experimental data. The soil texture and initial soil water content influenced the soil wetting pattern and the risks of surface runoff and deep percolation in sprinkler irrigation systems. When the water application rate was 11.35 mm h−1 with an irrigation duration of 10 h, it was easy to cause surface runoff in silty clay loam while deep percolation in loamy sand. Additionally, when the initial soil water content is high, it should be better to avoid irrigation or cut down the irrigation duration to prevent percolation. The water within the soil was more uniformly distributed than that applied through a sprinkler irrigation system. The uniformity coefficient of soil water content distribution (CUs) increased from 87.75 % to 95.56 %, as the uniformity coefficient of sprinkler irrigation (CU) increased from 40.74 % to 82.41 %. Although a higher initial soil water content brought a higher soil CUs value, it also led to a higher risk of percolation. The experimental and simulation results indicated that the COMSOL-2D model could be used to accurately simulate soil water movement in sprinkler irrigation and determine the suitable operation mode of low-pressure sprinklers.

Sprinkler irrigation uniformity assessment: Relational analysis of Christiansen uniformity and Distribution uniformity

AbstractChristiansen uniformity (CU) and Distribution uniformity (DU) are the most commonly used irrigation quality evaluation indicators, focusing on overall uniformity and local water deficit, respectively. Clarifying the quantitative relationship between the CU and DU has important production value for determining the water distribution characteristics of whole and localized areas in the evaluation of sprinkler irrigation water uniformity and improving the quality of sprinkler irrigation. This paper analyses the relationship between the calculation formulas of CU and DU based on mathematical analysis. The results reveal a prominent linear relationship between CU and DU, and the sum of the slope coefficient and the constant term of the linear relationship equation is 1. The value of the slope coefficient of the CU–DU linear relationship characterizes the differentiated form of the sprinkler water distribution. The slope coefficient is determined by the nozzle type, operating parameters and working scenarios. Notably, the specific form of the linear relationship obtained by fitting the experimental results in the literature is not universal. The mapping relationship between the value of the slope coefficient and the distribution form of sprinkler irrigation water quantity was established, and the influence of the value range of the slope coefficient on the DU of the overall and local sprinkler irrigation water quantity was demonstrated. The results show that the deviation rates of CU and DU decrease with increasing slope coefficient. When the slope coefficient is less than 1, CU is greater than DU; and the slope coefficient ranges from 0.46 to 1.36. When the slope coefficient is 0.625, the possibility of uniform irrigation is the highest. This research helps to overcome the limitations of CU and DU for irrigation uniformity evaluation and provides a reference for carrying out sprinkler irrigation uniformity evaluation with comprehensive characterization capabilities.

Extended Assessment of Sprinkler Irrigation Uniformity in Greenhouses Using GIS and Hydraulic Modeling

Traditionally, distribution uniformity has been obtained by using rain gauges, which makes it a very expensive process. This paper sought to create a simulation strategy using QGIS and EPANET, both free software, that allowed the simulation of the water application results of all the emitters of an irrigation installation. In this way, it was possible to obtain the geospatial representation of the applied water and finally to know the distribution uniformity in the whole installation. The simulation finally fulfilled its objective and was compared with a study of distribution uniformity with rain gauges. The biggest difference between the measured and simulated data was a difference of 5.76% among the sectors. The simulated uniformity was very similar to the measured uniformity, which allowed us to affirm that the proposed simulation methodology was adequate. We believe that the methodology proposed in this article could be very useful in improving the management of sprinkler irrigation systems, particularly those in which distribution uniformity is of special importance. These improvements in management can also result in savings in water and other inputs, which are becoming increasingly important in the current context of climate change and the reduction in the impact of agriculture on the environment. Finally, similar studies could be carried out with the same tools for other pressurized irrigation systems, such as sprinkler irrigation outside greenhouses and drip irrigation.

Development of an automatic test bench to assess sprinkler irrigation uniformity in different wind conditions

In sprinkler irrigation the water distribution uniformity in field conditions is not always a known factor, mainly due to the many variables involved, especially the wind. The main objective of this study was to design, install and test an automatic sprinkler bench to measure the irrigation uniformity of solid set systems for multiple wind conditions in real time. The system developed measures the different wind speeds and directions while simultaneously recording the rainfall distribution automatically. Consequently, the system requires little manual intervention, thus reducing the operating costs. All the information generated is stored in a database, obtaining multiple results of irrigation uniformity for each stable wind regime. As a second step, uniformities in different situations (layouts and wind directions) were studied. In addition, this study shows the potential for assessing the influence of different variables on irrigation uniformity for several sets of sprinklers. As an example of possible applications, 12,150 results of uniformity coefficients for conventional impact rotary head sprinklers with hexagonal nozzles in windy conditions were generated. These data were used to establish comparisons between different sprinklers. To do this, a multiple linear regression methodology was applied in order to analyse the influence of the different contour variables on the irrigation uniformity. The test bench presented along with the methodology to simulate and generate multiple scenarios constitutes a powerful tool for designers, farmers and technicians both for the improvement of existing installations and for future designs. The generation of a large amount of irrigation uniformity results for sprinkler irrigation in different wind conditions will lead to a large database with the potential to be able to determine the irrigation uniformity in all common scenarios.

Fertigation Uniformity under Sprinkler Irrigation: Evaluation and Analysis

In modern farming systems, fertigation is widely practiced as a cost effective and convenient method for applying soluble fertilizers to crops. Along with efficiency and adequacy, uniformity is an important fertigation performance evaluation criterion. Fertigation uniformity is defined here as a composite parameter consisting of irrigation and fertilizer application uniformity indicators. The field and computational procedures for sprinkler irrigation uniformity evaluation have been the subject of various studies. The objective of the study reported in this paper, however, is the development of an analytical framework for the evaluation and analyses of test-plot scale fertilizer application uniformity under solid-set sprinkler irrigation systems. Irrigation uniformity indices are adapted for use in fertilizer application uniformity evaluation. Fertilizer application rate, given as a function of irrigation depth and fertilizer concentration, is identified as the appropriate variable to express fertilizer application uniformity indices. Pertinent mathematical properties of the uniformity indices along with their practical fertigation management implications are outlined. Carefully designed hypothetical fertigation scenarios were analyzed to examine the significance of the interactive effects, of the local spatial trends of depth and concentration data, on the test-plot scale uniformity of the resultant fertilizer application rate data. The results of the study show that the spatial overlap patterns between depth and concentration data sets are the main determinants of test-plot scale fertilizer application rate uniformity. The study also shows that often the uniformity levels of irrigation and fertilizer concentration data sets cannot be uniquely related to the uniformity of the resultant application rate data. However, some practically useful qualitative relationships between the uniformity of irrigation depth, solute concentration, and application rate data sets are defined. Application of the approach presented here in the evaluation and analysis of fertigation uniformity data sets, measured under sprinkler irrigated conditions, is highlighted.

Sprinkler irrigation uniformity: Impact on the crop yield and water use efficiency

In this work, an assessment of the effect of distribution uniformity over water use efficiency is shown. The experimental study took place in Sebha region, southern Libya, characterized by arid climate and interested a barley field. The results of water irrigation in the sprinkler irrigation system with respect to the operating pressure (P) and raiser height of sprinkler (H) are reported with respect to distribution uniformity and water use efficiency. The main objective of irrigation is to apply the optimum amount of water to the crop root zone that is needed for its growth and maturation, and it is, hence, important for to check the uniformity of irrigation systems in order to adjust the operating parameters involved. To assess uniformity, the coefficient of uniformity (CU), the low quarter distribution uniformity (DU), and the coefficient of variation (CV) were considered, while the grain yield (GY), the crop height (CH) and the water use efficiency (WUE) weremeasured in order to find the best solution in terms of operating conditions. The highest values reached by the uniformity parameters with varying the operating conditions defined the best operating practices under which the irrigation system works efficiently: the results demonstrated that the maximum values for CU and DU, 91.37% and 0.85, respectively, were obtained at the highest P and H, and under the same conditions, also grain yield, plants height and WUE recorded the highest values: 5.50 t·ha−1, 63.49 cm and 0.75 kg·m−3, respectively. The results emerged in this work can be useful for similar arid regions like Sebha region, in order to solve the problems related to water scarcity and water use efficiency.

Sprinkler irrigation uniformity and crop water productivity of barley in arid region

An investigation has been organized To study the effect of the sprinkler irrigation system design on irrigation uniformity and its impact on barley crop yield and crop water productivity (CWP). The spring irrigation operating pressures (P) were 200 kPa (P1), 250 kPa (P2) and 300 kPa (P3). The sprinkler riser heights were 100 cm (H1), 125 cm (H2) and 150 cm (H3) from the ground. The results demonstrated that the maximum values of coefficient of uniformity (CU) and distribution uniformity (DU) (91.37 % and 0.85, respectively) were obtained at P3H3, while the minimum values (78.21 % and 0.71, respectively) were obtained at P1H1.Under P3H3 treatment, the highest values of 5.50 t ha-1 and 63.49 cm of grain yield (GY) and barely plant height (PH), respectively were recorded. The highest CWP value (0.75 kg m-3) was obtained when the P3H3 treatment was applied, while the lowest yield (0.36 kg m-3) was recorded under P1H1 treatment. According to the results of this experiment, under Sebha environmental conditions and similar regions, it is recommended to operate the solid set sprinkler irrigation system at P3H3 to obtain the highest CU and DU and consequently the highest GY, PH and CWP.

Effect of Combination Factors of Operating Pressure, Nozzle Diameter and Riser Height on Sprinkler Irrigation Uniformity

The irrigation uniformity of sprinkler irrigation system depends on many design factors such as nozzle type, nozzle diameter, operating pressure and riser height. An experimental study was performed to investigate the effect of combination factors of operating pressure, nozzle diameter and riser height on sprinkler irrigation uniformity. Different operating pressures, nozzle diameters and riser heights have been used. The irrigation uniformity coefficients such as coefficient of uniformity (CU) and distribution uniformity of low quarter (DUlq) have been studied. This study concluded that, the irrigation uniformity of sprinkler irrigation system was more affected by the combination of operating pressure, nozzle diameter and riser height.

Performance of new agricultural impact sprinkler fitted with plastic nozzles

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 400 kPa) and three nozzle diameters of the main nozzle (4.0, 4.5 and 5.0 mm) were performed to evaluate the radial water distribution curves, All the tests were performed under calm wind (≤1 m s−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 18 m × 18 m 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 2.5–6 m 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.

Design of Distribution Bench for Precision Measurement of Micro-Irrigation Sprinkler Irrigation Uniformity Coefficient

Micro-irrigation sprinkler irrigation uniformity coefficient is an important indicator of measuring the irrigation uniformity of micro-irrigation system and is an important parameter of micro-irrigation nozzle design. In order to test micro-irrigation sprinklers irrigation uniformity coefficient precisely, micro-irrigation sprinkler irrigation uniformity coefficient precision test-bed was developed. Test-bed can measure some parameters, such as on-site temperature, pressure, total flow, sub-flow and measurement time accurately. Collecting data through the data collect network. Multi-chip acquisition card is connected with RS485 bus and is connected to the host computer by numerical control system specially developed. The task of numerical control system is to process preliminary collected data, transfer the data to host computer, and coordinate with host computer to complete the task of control. It can also complete the several of control functions independently. Experiments show that the test-bed is reasonable designed, easy to operate and has a high test accuracy.

Evaluation model development for sprinkler irrigation uniformity based on catch-can dat

A new evaluation method with accompanying software was developed to precisely calculate uniformity from catch-can test data, assuming sprinkler distribution data to be a continuous variable. Two interpolation steps are required to compute unknown water application depths at grid distribution points from radial distribution of catch-cans’ data: using both radial and peripheral interpolations. Interpolation by cubic splines was used to give more accurately interpolated values. This method has higher accuracy theoretically compared with conventional methods to analyze catch-can data. Water application depths were calculated at each grid point and uniformity coefficients were computed from the grid distribution maps of water application depths. This has value in assessing application uniformity of sprinkle irrigation designs. Key words: Sprinkler irrigation, uniformity evaluation, model development, twice interpolation.

Assessing whole-field sprinkler irrigation application uniformity

In order to assess whole-field sprinkler irriga- tion uniformity, an experiment was conducted to obtain water distribution profiles at 23 different pressures for each of five different sprinklers: Nelson R33, Nelson R33LP, Nelson R33 with road guard, Nelson R33LP with road guard, and Rainbird Mini Paw/LG-3. A mathematical model was developed to account for pressure variation throughout a fixed sprinkler system on a 10-ha field and to evaluate sprinkler irrigation uniformity for the whole field using interpolated water distribution profiles from the experimental data. The relationships between irrigation application uniformity and sprinkler pressure, sprinkler spacing, pressure variation, sprinkler type, and field topography were studied using the model. The results show that the coefficient of uniformity, CU, decreases rapidly when the pressure is below the low end of the manufac- turer-recommended range; however, CU changes very little with pressure within the manufacturer-recommended range. The system application uniformity, CUsys, is usually less when pressure variations at different locations in a field are considered, and a simple previously published equation to predict CUsys is shown to closely approximate the CU from a more stringent calculation method. It was found that the impact of pressure variation (within the tested ranges) on application uniformity is less than that of the sprinkler spacing. Also, the effect of field topography on sprinkler application uniformity is relatively small for the cases tested herein.

Impact of Sprinkler Irrigation Uniformity on the Variability of Sugar Beet Leaf N Content

Impact of Sprinkler Irrigation Uniformity on the Variability of Sugar Beet Leaf N Content

Influence of lettuce as cover crop of the soil on sprinkler irrigation uniformity and parameters of efficiency

The effect of lettuce as cover crop was evaluated on sprinkler irrigation uniformity and parameters of efficiency. The experiment was carried out in field at the Universidade do Oeste Paulista, in Presidente Prudente, São Paulo, Brazil, from August to October, 2006. One treatment was performed on bare soil and the other using lettuce cultivar Vera as cover crop, at the end of the cycle. The average water depth, application rate, uniformity of distribution coefficient, Christiansen uniformity coefficient, Hawaiian uniformity coefficient, as well as the statistical uniformity coefficient were evaluated. The following plant spacing were simulated: 12 x 12, 12 x 18, and 18 x 18 m. The highest water depth retained with lettuce crop cover, at the end of the cycle was 2.4 mm, applied when sprinklers were spaced at 12 x 12 m. The same occurred in the application rate with an average reduction of 43%. When the overlapping was performed, the crop cover did not influence the parameters of efficiency and uniformity, assuring the distribution of the irrigation depth. Neither treatment reached the expected rate concerning the water depth average or the application rate in the spaces. The treatment using cover crop presented the lowest value, with a water depth average below the intended amount. Therefore, the lettuce as cover crop promotes the reduction of applied water depth. Consequently, the irrigation time has to be increased to assure the expected water depth.

EFFECT OF SPRINKLER IRRIGATION UNIFORMITY ON WHEAT PRODUCTIVITY, WATER LOSSES AND WATER USE EFFICIENCY

The current study was carried out at Agricultural and Veterinary Research Station, Faculty of Agriculture and Veterinary Medicine, Qassim University, Kingdom of Saudia Arabia during 2007/08 wheat growing season. The objective of this study is to investigate the effect of sprinkler irrigation uniformity on sprinkler irrigation uniformity coefficient on water losses by deep percolation, wheat crop yield and height, water use efficiency, uniformity coefficient of crop yield and height through field experiments. The other purpose is to obtain the response of wheat crop height yield to seasonal applied water. Treatments consisted of five sprinkler irrigation uniformity: CUc1 (>90- 80- 70- 60- 50- <55%). The results indicated that sprinkler irrigation uniformity coefficient affected all parameters of this study. By increasing sprinkler irrigation uniformity wheat crop yield, plant height, adequacy of irrigation and water use efficiency were increased while water losses by deep percolation and irrigation insufficient were decreased. High irrigation uniformity enhanced wheat growth, water use efficiency and worse water losses by deep percolation. Uniformity coefficient values for crop height, grain yield and water use efficiency of wheat were higher than the values of sprinkler irrigation Uniformity coefficient.

Effects of applied water and sprinkler irrigation uniformity on alfalfa growth and hay yield

This study was conducted to investigate the effects of applied water and sprinkler irrigation uniformity on alfalfa ( Medicago sativa L.) growth and hay yield in a semi-arid region. Field experiments were carried out in 2006 in Varamin, Iran, on three plots of 25 m × 30 m. Each plot was subdivided into 25 subplots of 5 m × 6 m. Different irrigation depths and sprinkler water uniformities were obtained by various scenarios of sprinkler nozzle pressure. In each plot, applied water was measured at 250 points (125 points above and 125 points below canopy) and the soil water content of 40 cm deep below soil surface was monitored at 25 points, each in the center of a subplot, throughout the irrigation season. The results showed that sprinkler water and soil water content uniformity varied between 66–78 and 88–91%, respectively. The findings revealed that soil water content uniformity was around 20% higher than sprinkler water uniformity. The irrigation uniformity below the canopy was estimated to be 2.5% greater than above the canopy, and canopy-intercepted water could account for 11–15% of the total seasonal applied water. Evaluation showed that alfalfa leaf area index relies more heavily on farm water application uniformity than hay yield and crop height. The experimental results illustrated that water distribution in sprinkler irrigation systems has a direct effect on alfalfa growth, hay yield and water productivity such that the applied water reduction and the increased sprinkler water uniformity led to an increased alfalfa water productivity of 2.41 kg m −3.

Uniformidade de aplicação de água, variáveis de produção e índice de área foliar da cultivar de feijão Iapar 57

O efeito da uniformidade da irrigação por aspersão sobre a cultura de feijão, Phaseolus vulgaris L. (Leguminosae-Faboideae), foi avaliado estudando o índice de área foliar e algumas variáveis de produção. Foram adotados quatro espaçamentos entre aspersores, correspondentes a quatro valores de coeficientes de uniformidade das irrigações realizadas. As variáveis estudadas foram índice de área foliar (IAF), número de vagem por planta, o número de grãos por vagem, a massa de cem grãos e o rendimento de grãos. Os resultados mostraram que a irrigação ótima para o máximo IAF foi a de máxima uniformidade, o que não corresponde ao ótimo para a produção

Effect of varying the distance of collectors below a sprinkler head and travel speed on measurements of mean water depth and uniformity for a linear move irrigation sprinkler system

A series of sprinkler irrigation uniformity tests were conducted to determine the effect of collector height and speed on applied water depth and uniformity from a linear move sprinkler irrigation system. Collectors, 102 mm in diameter and 200 mm in height, were set in the field according to the method outlined by ASAE [(2001). American Society of Agricultural Engineers. Test procedure for determining the uniformity of water distribution of center pivot and lateral move irrigation machines equipped with spray or sprinkler nozzles. ASAE Standards, ANSI/ASAE S436.1 MAR01] test procedures. The sprinkler system used in the study was a fixed plate sprinkler head with a 180° wetting pattern. Catch devices were placed to 300, 600, 900, and 1200 mm heights above ground and tested with 15 and 30 m h−1 speeds. The results indicated that mean sprinkler irrigation depths ranged from 45.5 to 51.4 mm and from 21.3 to 25.9 mm for 15 and 30 m h−1 system speeds, respectively. Mean coefficient of uniformity (CU) values for the same speeds ranged from 89.4% to 92.6% and 88.9% to 95.1%, respectively. Both irrigation water depth and CU measurements were significantly affected (p<0.05) by collector height but halving the irrigation system speed, apart from producing the expected doubling in water depth, produced no significant effects. Differences in collector heights could cause differences in irrigation depth and CU values of as high as 10 mm and 6%, respectively.

Modeling crop yield as affected by uniformity of sprinkler irrigation system

The effect of sprinkler irrigation uniformity on crop yield is an important consideration for the design of sprinkler irrigation system. A model that relates yield response to evapotranspiration deficits at special growth stages to evaluate the impacts of uniformity on crop yield was developed from a crop water production function. The simulation results of the model showed that crop yield increased with increasing uniformity. Optimum irrigation amount and uniformity for the maximum net return were determined with the model. The optimum irrigation amount depends on irrigation uniformity and on economic factors, decreasing with the uniformity but increasing with the ratio of product price to water cost. The optimum uniformity increased with an increase of irrigation amount expressed by a ratio between gross and required irrigation amount, but approximated 90% when the ratio exceeded 0.85. Field experiments conducted to study the relationship between spatial distribution of soil moisture and sprinkler application uniformity demonstrated that the water in the soil was more uniformly distributed than that measured for the application at the soil surface.

Modelling the effects of sprinkler irrigation uniformity on crop yield

This study reports the development and testing of a model which relates yield to irrigation amount and uniformity. Required input data are the Christiansen uniformity coefficient (CUC) and a parameter describing the sensitivity of crop yield to water deficits obtained from empirical relationships between evapotranspiration and crop yield. The model was used to determine optimum irrigation amounts for corn at Cordoba (Spain) under sprinkler irrigation. The economic impact of the accuracy in the ET estimates was assessed. The results were compared to those obtained with a crop growth model (Ceres-Maize) which was adapted to simulate the effect of irrigation uniformity on yield. The assumptions behind the use of CUC were experimentally evaluated. The results show that the optimum irrigation amount depends on irrigation uniformity, and on agronomic and economic factors. For maize production at Cordoba, the optimal ratio between gross and required irrigation requirements increased from 0.77 for CUC of 55% to 1 for CUC of 95% under high water prices. Crop simulation models and the simple model presented here are alternative tools for determining site-specific optimum irrigation amounts, with relatively low input data requirements.