Sprinkler Packages Research Articles

Evaluating Overhead Irrigation Sprinkler Packages in Utah

AbstractIn many areas where center‐pivot irrigation methods are used, the most common sprinkler package is called mid‐elevation sprinkler application, known as MESA. Two alternative sprinkler packages designed for better water use efficiency are called low‐energy precision application, or LEPA, and mobile drip irrigation, called MDI. A recent study evaluated how MDI and LEPA—at full and reduced irrigation rates—impact alfalfa and silage corn yield and quality in trials on two farms in Utah. Earn 0.5 CEUs in Soil & Water Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

On‐farm evaluations of overhead irrigation sprinkler packages at full and reduced rates

AbstractIrrigation is a critical resource in meeting the global demand for food, feed, fiber, and fuel. One water optimization method with high potential and interest is the use of more efficient irrigation systems. In many areas where pivots are used, the most common sprinkler package is mid‐elevation sprinkler application (MESA), which typically has application efficiencies near 80%. Low‐energy precision application (LEPA) and mobile drip irrigation (MDI) can have greater than 95% application efficiency. The objective of this research was to evaluate the ability of LEPA and MDI to maintain crop yield and quality in alfalfa (Medicago sativa L.) and silage corn (Zea mays L.), at similar and reduced irrigation rates as MESA. The intent of the reduced rate was to determine if the decreased application losses with LEPA and MDI could result in sustained crop production with a 20% irrigation rate reduction. Actual reductions ranged from 5% to 55% depending on system and site due to equipment constraints. Data from two farms in Utah during 2018–2020 provided evidence that these systems can often maintain yield and forage quality with 5%–55% less applied water. However, there were also many instances where yield was reduced by LEPA and MDI, even with similar application rates to MESA. This indicates that the two higher efficiency systems will not save water in all cases and that the application system must be carefully evaluated in small on‐farm trials over multiple years for its ability to succeed in specific field conditions.

Demonstration of Center Pivot Uniformity Evaluation and Retrofit to Improve Water Use Efficiency

Agricultural irrigation is a primary user for freshwater withdrawal. Irrigation plays an important role in crop production, as it provides the benefit of reducing the effects of prolonged dryness and erratic precipitation. Center pivot irrigation system is the most common irrigation system in agriculture. As the center pivot irrigation system ages, the system could develop a leaking joint, clogged sprinklers, and physical damage. This can cause areas of non-uniformity that can lead to under- or over-irrigated in some areas of the land, resulting in excess energy use and cost, wasting resources, and environmental impacts. Thus, it is important to evaluate the performance of a center pivot irrigation system regularly to maximize return on investments and minimize wasting resources. This study focuses on evaluating the impacts and benefits of improved center pivot irrigation distribution uniformity by performing distribution uniformity evaluations pre- and post-retrofit. This study also focused on demonstrating an unmanned aerial vehicle (UAV) to assess the performance of the center pivot irrigation system in two irrigated farmlands. The Coefficient of Uniformity (CU), Distribution Uniformity (DU), and Scheduling Coefficient (SC) were calculated based on the catch can test data. The values were utilized to evaluate water and energy savings from the improved coefficients. The team has found that replacing sprinkler packages increased the CU from 78 to 89 and the DU from 77 to 82, and reduced the SC from 1.3 to 1.2 in Field A. In Field B, replacing sprinkler packages increased the CU from 73 to 91 and the DU from 62 to 84 and reduced the SC from 1.6 to 1.2. The estimated water savings in Field A due to the reduced scheduling coefficient was approximately 151,000 liters/hectare/year, with consideration of the corn and soybean rotation field in Michigan. The estimated water savings in Field B was 608,000 liters/hectare/year. The data from this demonstration study showed the value of distribution uniformity evaluation and retrofit of irrigation systems. This information will encourage farmers and agricultural industries to consider performing more distribution uniformity evaluations, ultimately improving irrigation water use efficiency and supporting sustainable water management in agriculture.

Novel Monitoring System for Detecting Malfunctioning In-Canopy Sprinklers on a Center Pivot Irrigation System

The preservation of limited aquifer resources in the US Great Plains has driven the innovation and deployment of more efficient sprinkler packages for center pivot irrigation systems. One of the more efficient sprinkler packages available are in-canopy sprinkler packages, which hang low in the canopy. Although effective, they have the potential to become entangled in crop biomass and detach from the center pivot. Such detachments impact the efficiency and uniformity of the system, resulting in disrupted flow and pressure conditions, ultimately decreasing crop yield. Therefore, it is crucial that producers detect and replace missing in-canopy sprinklers immediately. A novel prototype monitoring system was designed using low-cost, publicly available technologies to monitor in-canopy sprinklers on a center pivot irrigation system and alert the user when and where an in-canopy sprinkler has become detached from the center pivot span. Later design revisions of the monitoring system introduced the ability of the monitoring system to also detect when a sprinkler became clogged. Experimental trials verified that the monitoring system operates efficiently and accurately; however, minor changes need to be made before large-scale implementation is possible.

Kansas Center Pivot Uniformity Evaluation Overview

Abstract. Center pivot irrigation systems are the most common system type in Kansas for a variety of factors – one of which is the ability to deliver a uniform depth of water application for a variety of crops and field conditions. Uniform applications are dependent on properly designed, installed and operated sprinkler nozzle packages. Uniformity evaluations were conducted as part of the Mobile Irrigation Lab (MIL) project to promote adoption of improved irrigation management practices with an emphasis on ET based irrigation scheduling. Since efficient and uniform water applications are critical to successful irrigation scheduling; MIL assessment included evaluation of sprinkler package performance using a single line catch can test. Catch can data was used to calculate the coefficient of uniformity (CU) and average application depth. The average CU value of the tested systems was 78.7 with a range of from 91.9 to 53.2. Many of the factors affecting pivot uniformity could have been identified and corrected with a visual inspection and/or comparison to the manufacturer’s sprinkler design specifications. Some of the catch tests indicated poorly designed and/or maintained sprinkler systems with reduced uniformity directly impacting crop performance, water use efficiency and economic results. Initial information was used in extension programs to illustrate the effect of various correctable sprinkler package deficiencies on performance and to encourage irrigation farmers to examine their nozzle packages and operating conditions. Keywords: Center pivot irrigation, Sprinkler packages, Uniformity.

Effect of Collector Size on Center Pivot Water Depth Catch

Abstract. The ASABE standard on uniformity testing of a center pivot system contains specifications on the collector size to measure the applied water depth. The standard was developed before many of the current sprinkler application devices were developed. A study was conducted to compare the catch depths of five collector sizes (opening diameters of 5.5, 10, 14.8, 20, and 27.4 cm, referenced as C2, C4, C6, C8, and C10) for three types of sprinkler application devices: spinning plate, fixed plate, and wobbling plate sprinkler systems using four 5x5 Latin squares. Each collector’s water depth was measured and statistically analyzed. Two analysis of variance (ANOVA) tests of the collector size effect were reported. Past experimental results were also compared to this experiment’s results, which generally reaffirms the difficulty of consistently measuring irrigation application depth within the practical range of collector sizes. Based on sprinkler application devices, fixed plate tends to have a more consistent depth caught compared to wobbling plate and spinning plate. If the ideal collector size selection was based on minimum variability of depth measurements, then either C6 or C4 collectors could be used. This study showed that within the range of sizes used, collector size does not substantially affect measurement of application depths for center pivot sprinkler systems. Despite the challenging task, measurement is probably within 5% if an appropriate number of collectors are used. Keywords: Catch can collector size, Center pivot irrigation, Sprinkler packages, Uniformity.

Effect of intra-irrigation meteorological variability on seasonal center-pivot irrigation performance and corn yield

Water application depth of a center-pivot (CP) irrigation system is not uniformly distributed across a field due to emitter package design, tower dynamics, and meteorological variability. The objective of this research was to measure and model the effect of the intra-irrigation meteorological variabilities on CP seasonal water distribution pattern and corn yield. The 2013 irrigation season of a commercial CP cropped with corn was analyzed. From 60 irrigation events applied to the corn, 10 were evaluated using radial catch cans. The mechanical movement of CP towers for the sixty irrigation events was characterized using Global Navigation Satellite System-Real Time Kinematic (GNSS-RTK) monitoring. Meteorological variables at 1s frequency were measured with an automatic weather station installed in the farm. The ballistic model calibrated and validated for rotating spray plate sprinklers under different nozzle sizes and wind conditions was mounted on the CP lateral, following the correspondent sprinkler package. The CP lateral was moved following the measured or simulated tower dynamic, and the current or averaged meteorological conditions of each irrigation event were applied to the corn. Crop yield was simulated by coupling the water distribution pattern simulated under the different cases with the Ador-crop model. Differences were observed for simulated seasonal water distribution pattern of the CP under homogeneous wind conditions (averaged for each irrigation event) or under variable of time wind conditions (measures). Simulated yield considering discontinuous tower dynamics and intra-irrigation meteorological variability has the largest correlation coefficient with the measured corn yield. Other factors were not considered in the yield simulation as variability in nutrient availability, emergence problems, and diseases and soil variability could explain the differences between the simulated and measured corn yield. The intra-irrigation meteorological variability has an important effect on the water distribution pattern of windy irrigation events of CP systems. Depending on the wind speed along the crop season, the intra-irrigation variability will have a major or minor effect on seasonal water distribution pattern and crop yield variability.

Effect of the start–stop cycle of center-pivot towers on irrigation performance: Experiments and simulations

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).

DEPIVOT: A model for center-pivot design and evaluation

Center-pivot sprinkler irrigation became very popular. Hence, aimed at farmers advising, the simulation model DEPIVOT has been developed with the objective of design new systems or changes in systems in operation. The software consists of a simulation package developed in Visual Basic and data base in Access. The model comprises five main sub-models for: (a) computation of the gross irrigation requirements; (b) sizing of the lateral pipe spans through the hydraulics computation of the friction losses and respective operative simulation considering to the effects of topography and the possible requirements of an end gun; (c) selecting a sprinklers package with computation of pressure and discharge at each outlet and including the consideration of pressure regulators; (d) verification of the sprinklers package through estimation of runoff potential by comparing application and infiltration rates at selected locations along the lateral; and (e) estimating the expected uniformity performance indicators when in operation. The user verifies if performance is within target values set at start and may develop and compare alternative sprinkler packages until appropriate conditions are obtained. When the model is used for evaluation of systems under operation using data collected in farmers’ fields performance indicators are computed and, responding to farmers’ needs, the model may be used to design changes in the existing systems and to improve management. This paper describes the model and shows examples of applications to select a sprinkler package and assess the respective runoff potential.

Selecting Sprinkler Packages for Center Pivots

Center pivots are the primary method of irrigation across the U.S. Great Plains. Center-pivot irrigation is also the fastest growing method of irrigation in the U.S. and around the world. Pivots have the potential to be very efficient and uniform if sprinkler devices are properly selected for local field conditions. New water application devices provide for selection that minimizes runoff and controls droplet sizes to reduce evaporation and drift losses. We present updates to models for computing runoff potential based on characteristics of sprinkler devices and soil textural classes. A dimensionless solution to the Green-Ampt infiltration method for center pivots is presented to better understand factors that influence runoff. That analysis shows that two dimensionless factors are needed to assess the runoff potential. One scaling factor is based on system design, and the second factor is based on irrigation management. An evaporation routine has also been incorporated to estimate potential evaporation losses that may result from utilization of a specific sprinkler design. Modeling runoff and evaporative losses simultaneously allows for comparison of tradeoffs in sprinkler package selection.

EVALUATION OF IRRIGAGE COLLECTORS TO MEASURE IRRIGATION DEPTHS FROM LOW PRESSURE SPRINKLERS

Coarse-grooved, fixed-plate sprinkler deflector pads provide distinct streams or jets of water that are not easily distorted by wind and minimize evaporative losses. However, these sprinklers provide variable, cyclic, and nonuniform application patterns of applied water that are difficult to accurately measure with collectors that have small openings. In 1999, 2000, and 2002, field studies were conducted to compare the measurement effectiveness of a non-evaporating sprinkler irrigation catch device (IrriGage) with larger collectors. The standard IrriGage has a 100-mm diameter opening, a 200-mm long collector barrel, and an attached storage bottle for collected water. These characteristics exceed current ASAE standard (ASAE S436.1) recommendations for sprinkler collectors. IrriGage collectors were compared to other catch devices that included 430-mm diameter pans (PAN) in 1999 and 2000, and a single row of 150-mm diameter collectors (150-S) similar to the IrriGage in 2002. IrriGage collectors were tested under three different sprinkler irrigation packages that included fixed-plate deflector pads with coarse grooves, spinning plates, and wobbling plates. In 1999, IrriGage collectors positioned with openings at a 1.2-m height within a corn canopy measured lower irrigation depths and different sprinkler patterns as compared to the larger diameter PAN collectors that were positioned in an adjacent grass buffer. In 2000, the 100-S collectors were lowered to a 600-mm height and repositioned into the grass buffer with the PAN collectors. The resultant measured irrigation depths and data variability for the IrriGage collectors were significantly greater and distributed differently than associated data from the PAN collectors. In 2002, a single row arrangement of IrriGage collectors (100-S) under the fixed plate sprinkler package had significantly greater irrigation depths (14% to 25%) and greater variances in collected data than the 150-S collectors (similar to 2000 results). However, while measured depths under spinning and wobbling plate sprinklers with 100-S collectors were 2% to 9% greater than measured depths with 150-S collector, differences were generally not significant. Furthermore, individual collector data between 100-S and 150-S collectors under the spinning and wobbling plate sprinklers tracked very well. Additional tests included multiple collector tests using inline (100-IL) and side-by-side (100-SS) arrangements of the 100-mm IrriGage collectors. Results from these tests showed that the 100-IL and 100-SS arrangements did not improve catch accuracy when compared to the individual 150-S collectors. The current ASAE standard (ASAE S436.1) for collector size criteria requires a minimum entrance diameter of just 60 mm. Based upon the field results of this work, the current standard collector size criteria are not appropriate for the low pressure, fixed plate, coarse-grooved sprinklers that provide distinct streams of water with little pattern breakup. Additional research is needed to determine an appropriate collector size (and perhaps shape) for the measurement of irrigation depths from center pivot and linear move irrigation machines with lower pressure sprinkler packages.

MEASURED AND SIMULATED UNIFORMITY OF LOW DRIFT NOZZLE SPRINKLERS

Field measurements conducted on largescale irrigation systems with fixedplate, low drift nozzle (LDN)sprinklers showed that coefficient of uniformity (CU) values ranged from 70 to over 90. Measured CU values were typicallylower in value for the lower operating pressure systems and for sprinkler packages with wider spacings. Measuredsinglesprinkler distribution patterns were then used in an overlapping sequence with specific sprinkler spacing scenariosto simulate multiplesprinkler distribution patterns for moving systems. Scenarios included sprinkler operating pressures of41, 69, 104, and 138 kPa; sprinkler spacings of 1.83, 2.44, 3.05, and 3.66 m; and nozzle orifice sizes of 4.76 to 7.94 mm witha flow range of 0.16 to 0.77 L/s. Simulated patterns and CU values compared well with fieldmeasured patterns and CU values for the respective sprinklersize, spacing, and operating pressure combinations. CU values from simulated patterns were highest for closer sprinklerspacing scenarios (

Decision Support System for Design of Center Pivots

Sprinkler irrigation package selection for center pivot systems depends on soil type and affects water and energy use. A decision support system (DSS) was developed to provide designers and irrigators with a rapid method to analyze many design alternatives. A digitized soils database is accessed by the DSS to determine the predominate soil for each 0.64-ha parcel of land in a center pivot field or site. Flow rates needed to meet crop water requirements and expected application losses are calculated and spatially averaged based on these water requirements for each cell. Uniformity of the irrigation applications are estimated for level land only. Energy usage for various sprinkler packages and power sources can be analyzed. Potential runoff from each cell is displayed by the DSS. The user selects the parameters for multiple system comparisons. The DSS enhances the analyses of management information seldom utilized in current design methods and presents the results of database lookups and numerical model calculations in easy-to-interpret graphical formats. The design can then integrate the users’ attitudes and values regarding energy and water savings.

Effect of Various Chemigation Methodologies on Suppression of the Fall Armyworm (Lepidoptera: Noctuidae) in Corn

Studies were conducted in Tifton, Georgia during 1989 to compare the effectiveness of center-pivot irrigation sprinkler packages and various formulations of insecticides for the control of fall armyworm, Spodoptera frugiperda (J. E. Smith), infesting corn. Chemigation with Whirl-jet (E53) sprinklers provided better control of the pest than impact sprinklers or a Pass system. Chemigation with whirl-jet sprinklers controlled fall armyworm as well as a conventional hi-clearance sprayer. Asana XL 0.66 EC + oil chemigated with an irrigation simulator provided the most consistent control of fall armyworm larvae in whorl stage corn when compared with Asana XL + water, Lorsban 4E + oil, Lorsban 4E + water, Lorsban 6 (tech.) + oil, Larvin 3.2 + oil, and Larvin 3.2 + water. All tested materials resulted in significant reductions in fall armyworm damage to the whorls of corn.

Sprinkler Irrigation Runoff and Erosion Control Using Interrow Tillage Techniques

A continuous-application rainfall simulator was used to apply water at rates similar to the peak rates of center pivot irrigation systems equipped with low pressure spray sprinkler packages. Three interrow tillage treatments implanted reservoir, basin till, and subsoilerwere compared to conventional tillage for two field slope conditions (1% and 10%). Tillage that provided increased levels of surface storage provided the most effective means of controlling both runoff and soil erosion. At 10% field slope, the implanted reservoir reduced runoff by 68% and soil erosion by 92% compared to the conventional treatment. There was significantly greater soil erosion on the subsoiler treatment than on the basin till, implanted reservoir, or conventional treatments for 10% field slope conditions. However, at 1% field slopes, the subsoiler treatment was comparable to the implanted reservoir with respect to amount of water runoff and soil erosion. At 10% field slopes, the conventional treatment resulted in greater erosion than the implanted reservoir and basin till treatments. However, at 1% field slopes, no difference in runoff volume was measured.

Analysis of Center Pivot Irrigation Systems Operating in a Humid-Area Environment

ABSTRACT Acomputer model was developed to analyze the economics of center pivot irrigation systems on various intake rates of soils in the humid Southeastern U.S. Seven system sizes and four sprinkler application packages were analyzed for peanut production. An analysis of input parameters was performed to determine the magnitude of impact of the model components on the selection of the most economic sprinkler package.

A System for Measuring Infiltration Rates Under Center-Pivot Irrigation Systems

ABSTRACT Asystem for measuring the apphcation rate, potential runoff and the soil infiltration rate under center-pivot irrigation sytems was developed. The infiltrometer is similar to the Purdue-Wisconsin type with improvements to increase the utility, portability and accuracy of the apparatus. The primary improvements in the system are the addition of an electronic water level sensor and a digital data logging system. The experimental procedures developed for using these instruments under a center-pivot irrigation system are also described. Results of tests for the various types of sprinkler packages and spray nozzles are presented to demonstrate the use of the infiltrometer. The performance of the individual components was satisfactory and the vacuum infiltrometer provided a measure of the potential runoff under the center-pivot irrigation systems.

Chemigation in Corn: Effects of Nonemulsifiable Oils and Sprinkler Package on the Efficacy of Corn Borer (Lepidoptera: Pyralidae) Insecticides

Second-generation southwestern corn borer (SWCB), Diatraea grandiosella (Dyar), and European corn borer (ECB), Ostrinia nubilalis (Hubner), were effectively controlled by insecticides applied in irrigation water. In 1983, two applications of fenvalerate (0.17 kg/ha) or chlorpyrifos (0.84 and 1.12 kg/ha) gave 98 and 75% control of SWCB, respectively, and 92 and 97% control of ECB, respectively. There was no advantage to adding oil in this test. In 1984, one application of fenvalerate (0.17 kg/ha), chlorpyrifos (1.12 kg/ha), or encapsulated methyl parathion (1.12 kg/ha) gave 40, 42, and 88% control of ECB, respectively. With the addition of a nonemulsifiable oil (1.18 liters/ha), efficacy of these insecticides was 71, 80, and 87% control, respectively. In two tests, ECB control was significantly higher under high-pressure impact sprinkler packages (350–410 kPa) than under low-pressure drop nozzle packages (140 kPa). In 1984, there was a significant increase in spider mite populations in plots treated with chlorpyrifos or fenvalerate applied without nonemulsifiable oil. However, when these insecticides were applied with nonemulsifiable oil the increase in spider mite populations was not significant. Spider mite populations were significantly higher in treatments applied with low-pressure drop nozzles than in treatments applied with high-pressure impact sprinklers.

Suitability of Reduced Pressure Center‐Pivots

Selection criteria for reduced pressure center‐pivot irrigation systems are developed. An analysis of the combined effects of the application rate characteristics or center‐pivot irrigation systems and the Soil Conservation Service (SCS) soil intake family curves is used to determine the maximum depth of water which could be applied per irrigation for various types of soils and sprinkler packages. These irrigation depths are used to determine guidelines for proper selection of reduced pressure center‐pivot systems. The results can be used as a general guide to determine if a particular system may have a runoff problem under a given situation.

An Experimental Center-Pivot Irrigation System for Reduced Energy Crop Production Studies

ABSTRACT AN experimental 52.6 ha center-pivot irrigation system for studies of reduced energy crop production systems is described. The system consists of high pressure impact sprinklers, low pressure impact sprinklers, and low pressure spray nozzles that are automatically turned on or off at preselected locations in the field. The control procedures ofthe system operation are described. The system also has the capability of applying different depths of water per irrigation as a function of position radially outward from the pivot point. Four years of data indicate that the system controls function properly and the design irrigation depths are being met. The concept of rotational uniformity or the spiking of water application as the pivot rotates is presented. Field measurements of water distribution of the different sprinkler packages indicate that rotational uniformity appears to be a problem only on the spray nozzle system and only for those systems applying relatively small application depths. The low pressure spray nozzles have the lowest uniformities while the high pressure impact and low pressure impact sprinklers have nearly identical uniformities.