Suitability of Reduced Pressure Center‐Pivots

Gilley, James R.

doi:10.1061/(asce)0733-9437(1984)110:1(22)

Cited by 22 publications

(12 citation statements)

References 6 publications

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“…Figure 13.13 provides a "management guide" for avoiding runoff during water application (Gilley, 1984;Martin et al, 2007). The figure uses the important factors that we've just discussed to indicate how much water can be applied and yet avoid runoff.…”

Section: Depth Of Water Appliedmentioning

confidence: 99%

Center Pivots and Lateral Moves

2021

Irrigation Systems Management

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In 1948 Frank Zybach invented a device he called the "self-propelled irrigator." This led to the development of center pivot and linear or lateral move irrigation systems (Bittinger and Longenbaugh 1962;Heermann and Hein, 1968). A chapter is devoted to these systems because of the unique management needed to capitalize on the capability of these systems. Additionally, the growth of center pivot irrigation during the last three decades far exceeds the growth of any other method of irrigation. In some areas the amount of land irrigated with surface systems has receded. Many of the fields, previously surface irrigated, have been converted to center pivot irrigation. The growth in center pivot irrigation in one year almost equals the total amount of land irrigated with microirrigation in the U.S. The growth has been very substantial and will likely continue. Three principal reasons drive this growth. First, the systems have the ability to be very efficient. They can apply small depths of water at the time that the crop needs irrigation. Second, the systems require less labor than surface or moved lateral systems. In many areas the scarcity of available labor is a limitation to the amount of land that a farmer can irrigate. Third, the systems have the capability to irrigate crops, soils, and terrains that are infeasible with surface, or periodically-moved sprinkler systems.The basic components of a center pivot (Martin et al., 2007) are illustrated in Figure 13.1. The pivot lateral is a pipeline with sprinkler outlets. The pivot lateral is supported by a tower assembly. The towers include a structure to support the pipeline plus a motor to propel each tower. Today most pivots are powered by electricity. However, some manufacturers use oil hydraulic motors. The pivot base or pivot point is located at the center of the field. The base can be permanently installed or, for smaller systems that are towed from field to field, the base is mobile. Water is supplied to the inlet pipe on the pivot base. The water is pressurized by a pump upstream of the pivot. Water is carried up the pivot base through a rotating elbow to the inlet of the pivot lateral. Power is supplied continuously to motors installed at each tower using a slip-ring assembly. This device contains contacts that allow the pivot to pick up power from the pivot base while the lateral rotates. A control panel is usually located on the pivot base where the operator can adjust the speed of rotation of the pivot and check on other factors. A road is usually necessary so the operator can conveniently reach the pivot base.The combination of the pivot lateral, the truss support structure, sprinkler devices, and the tower are called a span. The length of a span can vary from 100 to 200 feet. Installation costs are less with longer spans; however, the maximum length of a span is determined by the diameter of the pipe and the slope and undulation of the terrain. The length of a span can vary along the pivot to adjust to the dimensions of the field. Spans of the pivot can b...

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Section: Depth Of Water Appliedmentioning

confidence: 99%

Center Pivots and Lateral Moves

2021

Irrigation Systems Management

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“…Figure 13.13 provides a "management guide" for avoiding runoff during water application (Gilley, 1984;. The figure uses the important factors that we've just discussed to indicate how much water can be applied and yet avoid runoff.…”

Section: Irrigation Systems Managementmentioning

confidence: 99%

Irrigation Systems Management

2021

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Like most textbooks, this book grew out of our desire to have written material that matches the educational needs of both the students and the instructor of a college course, in this case a course entitled Irrigation Systems Management. The book is the culmination of course notes which have been in development and use for nearly 30 years.The emphasis of this book is on the management of irrigation systems that are used for agricultural crop production. There are two distinct components of the book, starting with the soil-water-plant-atmosphere system and how soil water should be managed to achieve the desired crop production outcomes. This includes in-depth presentations on soil water storage and movement, plant water use, managing the soil water reservoir through irrigation scheduling, and salinity management. The book then shifts to the second component, which is the description and management of the various forms of agricultural irrigation systems along with their water supply. Whether it be a surface, sprinkler, or microirrigation system, the irrigation manager must not only know how much water to apply but also how to manage the system itself to achieve efficient application. High application efficiency can only be realized by minimizing runoff, deep percolation, evaporation, and drift onto non-target areas. Since energy costs are an integral part of the management equation, one chapter in the book deals with the hydraulics and energy requirements of pumping and distributing water. One of the key themes spread throughout the book is providing guidance to irrigation managers on how to improve irrigation water productivity (production per unit of irrigation water) and minimize water resource contamination.Our goal is for the reader to understand the complexities of irrigation systems and how they are to be managed to meet the water needs of the crop production system. This is not an irrigation engineering design book; we have purposely minimized the presentation of design steps and the supporting equations. The intended audience of the book is upper-level undergraduate students and graduate students who are pursuing degrees in Agricultural or Natural Resource Sciences. Example majors include Agricultural Systems Technology, Agronomy, Crop Science, Mechanized Systems Management (or equivalent), Natural Resources Management, Soil Science, and Water Science. We expect the reader to have a basic understanding of soils, crops, physics, and the application of algebraic equations. We have also tried to add enough advanced material to challenge graduate students when the book is used in courses that are taught simultaneously at the undergraduate and graduate level. We hope the book will match the needs of students who plan to work in irrigation and related industries, university extension and outreach, private consulting, government service, or production agriculture and that it will continue to serve as a useful reference to them following completion of their formal education.The book is being published by the Americ...

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“…Temporal variations in the value of the application rate of water in central pivot are analyzed under the assumption that during the time interval corresponding to the time of wetting, the application rate of water follows a template elliptical (KINCAID et al, 1969;DILLON et al, 1972;GILLEY, 1984;BERNUTH & GILLEY, 1985). However, others believe that the parabolic profile (LUZ & HEERMANN, 2005) or the trapezoidal pattern (DEBOER et al, 2001;KINCAID, 2005) are more suitable.…”

Section: Introductionmentioning

confidence: 99%

Water distribuition characteristics and soil loss of LEPA Quad-Spray emitter nozzles

et al. 2013

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ABSTRACT:The objective of this study was to characterize water application rate, water application pattern width, flow rate, water distribution uniformity and soil loss caused by nozzles of the Low Energy Precision Aplication (LEPA) type Quad-Spray emitter. The study was carried out at the Hydraulic and Irrigation Laboratory of the Department of Engineering at the Federal University of Lavras, in Lavras, state of Minas Gerais -MG, Brazil. Twenty-two (22) LEPA QuadSpray emitter nozzles were evaluated, with nozzle diameter ranging from 1.59 to 9.92 mm. The experimental design used was entirely randomized, with three replications. Increasing values of nozzle flow rate ranging from 77.44 up to 3,044 L h -1 , were obtained with increasing nozzle diameter sizes. Application pattern width ranged from 0.56 up to 3.24m, according to nozzles diameter size. Low values of CDU (maximum of 35.73%) were observed when using the QuadSpray nozzles. Observed average water application rates covered the range between 68.05 mm h -1 (the lowest value that was obtained with the 2.38mm nozzle) and 258.15 mm h -1 (the highest value that was observed with the 9.92 mm). Average water application rates increased in a simple nonlinear function with the increase of nozzle size diameter. However, the weighted average increase in the amount of soil loss by erosion was not related to the increase of weighted average water application values.KEYWORDS: technical characteristics of the Quad-Spray, resizing of nozzles, erosive impact. CARACTERÍSTICAS DE DISTRIBUIÇÃO DE ÁGUA E PERDAS DE SOLO DE BOCAIS DO EMISSOR QUAD-SPRAY TIPO LEPARESUMO: Foi objetivo deste trabalho caracterizar a taxa de aplicação de água, largura do padrão molhado, vazão, uniformidade de distribuição de água e perdas de solo de bocais do emissor QuadSpray tipo Low Energy Precision Aplication (LEPA). O trabalho foi realizado no

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Suitability of Reduced Pressure Center‐Pivots

Cited by 22 publications

References 6 publications

Center Pivots and Lateral Moves

Center Pivots and Lateral Moves

Irrigation Systems Management

Water distribuition characteristics and soil loss of LEPA Quad-Spray emitter nozzles

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