Building a Center Pivot Irrigation System

This video shows how to build a Center Pivot Irrigation System.

Theft of copper wire

Hamilton County Sheriff’s Deputies arrested five area residents on Sept. 4 on charges of grand theft and felony criminal mischief in connection with the theft of copper wire, according to sheriff’s reports.

The five, four adults and one juvenile, all admitted guilt, according to Hamilton County Sheriff’s Office arrest notices.

In the reports filed by Sheriff’s Office Investigator Sergeant David Ehlert, copper wire from the tops of eight pivot irrigation systems in Hamilton County had been stolen between Aug. 10 and Sept. 1. The cost of the repairs to the pivots range from $2000 to $13,000, said Ehlert.

The five were booked into the Hamilton County Jail. The four adults remained in jail as of Wednesday, held on $60,000 bond each.

Giant green circles

Travelers looking out airplane windows while flying across the United States may wonder what creates those giant green circles so visible from 30,000 feet.

The circles are crops irrigated with a self-propelled sprinkler irrigation system that rotates around a central point commonly called a “center pivot system” or “center pivot.”

Center pivots are so common that many people are surprised to learn they have existed only about 50 years. The center pivot's inventor, Frank Zybach received a patent for a “Self-propelled Sprinkler Apparatus” in July 1952.

The center pivot is the first, and most successful, robot for production agriculture. The center pivot can be used to irrigate from one to more than 600 acres. Varying the length of pipe or adding a corner attachment will allow center pivots to irrigate almost any size or shape field. An operator only has to turn on the water pump, start the center pivot and wait until the system completes its journey across the field, which can be scheduled from 12 hours to 10 days, depending on the volume of water applied.

Center pivots are used on about one-third of the irrigated land in the United States. In the Great Plains, they irrigate more than 90 percent, and that percentage is increasing each year.

Growing rice with center-pivot irrigation saves water and fuel

Rice is an important crop in many places, and a staple food for many people worldwide. Traditionally, rice is grown with flood irrigation, a method that reduces weeds but is labor-intensive, requires lots of water and limits production to areas with the right climate and soil.

Some experiments are looking at a new way of growing rice, one that could expand rice production to places where it had been thought impossible.

Researchers are experimenting with center-pivot irrigation, an overhead sprinkler system commonly used on corn and soybeans. On rice, the technique requires less labor, water and fuel than traditional rice farming.

The main purpose of this experiment is to reduce water. It's possible to use half the water and energy with this system compared to a traditional rice field. The experiment was started in the spring, comparing the performance of pivot-irrigated rice to a traditional flooded rice field. The pivot showed its water-saving potential after just a few weeks.

On the flooded field, they used about 2 million gallons of water on a 6-acre field in just two-and-a-half weeks. On the pivot system, they hadn't even put out 1 million gallons yet and they had been watering for probably three weeks longer.

The method could triple rice production. With center-pivot irrigation, it would be possible to grow rice on fields with hills. It really opens up possibilities to other farmers who couldn't grow rice before.

Pivot water use in Nebraska

Center pivot irrigation systems consume a lot of water in Nebraska. 

Municipal supplies, domestic users, industries, commercial businesses, livestock and power plants are among the users of Nebraska’s water resources. None, however, use as much of Nebraska’s water as farmers irrigating their crops.

A new educational effort by University of Nebraska-Lincoln Extension seeks to inform center pivot irrigation operators on best practices aimed at reducing water consumption. In an unusual display of camaraderie, the major competing players in Nebraska’s center pivot irrigation industry have joined forces to help in the effort.

Valmont Irrigation of Valley, Reinke Manufacturing Co. of Deshler, T-L Irrigation Co. of Hastings and Lindsay Corp. of Lindsay will work with their dealers to hold educational sessions this winter for center pivot operators.

The way center pivots are managed and maintained can affect water consumption. The state must reach a “sustainable balance” of water users and supplies in these areas. 

Many center pivot users need additional information on properly managing and maintaining their systems in ways that conserve water. Higher fuel prices and land values and water shortages have changed the way operators must manage their units.

Precautions when working with irrigation systems

The following precautions should be taken when working with irrigation systems involving the use of electricity:

• Make certain only well-trained people familiar with the National Electrical Code and the new irrigation standard are allowed to work on the wiring.
  
• When servicing the machine, personally shut off and lock the master control switch.
• Stay away from the machine during lightning storms. A properly installed machine is an ideal lightning receptor and will carry the current for long distances.
• Install lightning arresters to protect equipment.
• Mark the location of all buried electrical lines.
• As with any electrical system, do not over-fuse. Instead, find out why the fuses are blowing and correct the problem.
• Don't cut corners on the electrical installation to save money. Include the cost of the electrical components when estimating the cost of your system.
• Avoid contact with overhead lines when moving equipment.
• Use the disconnect switch located at each tower when working on the system. It is there to protect a person from injury if someone accidentally energizes the system or if the system automatically restarts after a power outage. The Occupational Safety and Health Act (OSHA) requires the switch to be within 15 feet of the motor.
• If you feel a tingle when you contact any part of the system, shut it down until a competent electrician can troubleshoot the system.
  

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Center Pivot Sprinklers

Sprinkler manufacturers have developed and marketed a large number of different sprinkler technologies that produce relatively large wetted diameters at reduced pressures.Thus, center pivot operators have a greater number of sprinkler packages to meet goals of reduced wind drift, reduced energy costs and increased water application efficiency.

The goal of every sprinkler or spray nozzle package is to apply water uniformly to the soil surface where it can be used by plants to produce grain or dry matter.Some performance characteristics can affect the suitability of a package for a specific set of field conditions.

Each sprinkler is designed to operate within a range of water pressures. Tipically, impact sprinklers can be operated over a wide range of pressures than low pressure spray nozzles.

One of the more recent changes resulting from new nozzle designs is related to water application patterns.The design process sought to achieve the largest wetted diameter and lowest operating pressure combination possible.

Water Applications for Center Pivots

Today, the value of center pivots has increased even further as the tools available in the form of computer controls and sprinkler technology have reached a new plateau.

Center pivot applications have also expanded into the realm of applying not only water but also nutrientsand chemicals to the crop via fertigation and chemigation. Advances in sprinkler technology for mechanized irrigation have answered many of the previous challenges.

Today a grower can apply water and chemicals with precision uniformity and high irrigation efficiency. The improvements in irrigation efficiency, uniformity, andthe control of runoff illustrate major technological advancements.

REASONS TO RENOZZLE YOUR PIVOT SYSTEM

1. To add pressure regulators to compensate for pressure fluctuations and stabilize flowrate.
2. To replace old technology for better irrigation efficiency.
3. To improve irrigation uniformity.
4. To operate at lower pressure and save energy.
5. To improve crop yield and get a higher return per acre.
6. To adjust gallonage to match soil and crop requirements.
7. To replace worn out sprinklers and nozzles.
8. To minimize operating costs.
9. To take advantage of local power
10. To reduce runoff and solve wheel-tracking problems.

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Electrical inspections in Center Pivot Systems

Many irrigators have received minor tingles while working around electrical irrigation machinery. Under pressure to keep the system running, they tend to ignore warning signs until serious injury occurs. Two electrical inspection surveys point out the dangers of such practices.
A rural power supplier conducted a series of electrical tests and inspections of electrically driven Center Pivot Systems with electric pump motors. The survey showed 37 % were potentially hazardous because of the lack of a grounding conductor. Nearly 40 % did not have a ground rod installed. More than 50 % failed to have a fuse or a means of disconnection. Other hazardous situations were found, including loose connections, improper circuit and motor protection and deteriorated insulation.
A second series of inspections showed similar results. Of 77 systems inspected at the owners' requests, 10 were classified as lethal; 38 were definitely hazardous; the remaining 29 were potentially hazardous. The 10 lethal systems had current flowing to ground at the time of the inspection or had almost killed someone shortly before the inspection. The National Electrical Code (NEC) had been violated in all 77 installations.

Chemigation using Center Pivot Irrigation machines

Chemigation is the application of agricultural chemicals such as pesticides or fertilizer with irrigation water. When used properly, chemigation is an environmentally sound and cost-effective way to apply many chemicals during the growing season. Safe and effective chemigation is accomplished by combining both good management and good equipment.

A very important part of management is accurate calibration. This fact sheet covers procedures for calibrating chemigation when using Center Pivot Irrigation Machines.
Chemigation calibration is the process of establishing how fast the center pivot will cover the field and adjusting the injection pump to apply the desired quantity of chemical per acre. Calibration insures that the proper amount of chemical is being applied thereby giving the highest economic gain and minimizing environmental risks.
Calibration is especially important when applying pesticides where specific label rates must be followed. The procedure for calibration is straight-forward, but it does involve a significant time commitment, an understanding of chemigation concepts, and basic mathematical skills. You will need to spend time and effort calibrating before any chemical is applied.
It is necessary that all parts of the irrigation and chemical injection system are operating properly. All chemigation safety equipment should be installed and operating (see FS 860 Chemigation Safety).
Always check the irrigation system for operating problems and uniformity of water distribution. Some older-style systems such as water drives may not have good water distribution because more water from the drive goes near the wheel track. Make sure that the nozzles are not worn and that all sprinklers are operating properly. Remember that the chemical can be applied only as uniformly as the water applied.
The irrigation system and the injection system must be calibrated. You need to know the following information when calibrating: acres covered, time to cover the field, depth of water applied, chemigation application rate, amount of chemical, injection rate.
Besides the chemigation equipment, other items to help with calibration include a stopwatch, calculator, long measuring tape, marking stakes or flags, and a calibration tube.

Pessimistic rain forecasts in Spain

Spain faced up to the most serious drought in the last 60 years, (aquifers level was near a quarter of its size). The poor rains achieved this year were not enough to fill reservoirs, and water consumption limitations started to be aplied.
The Spanish Ministry for the Agriculture promissed transforming 138,000 hectares with a 1,137 mill. € budget, (76%, public investment). Besides, it would improve existing irrigation lands with a 3,056 mill. € (50%, public inventment). These works were directed and guided by the respective official institution in each area. They pointed out the specifications to which, installing enterprises which took part in the works execution, were obliged to.
One of the aims was the water control with the help of counters installation. The specifications indicated technical and administrative prescriptions for volumetric counters installation and support. These counters should have European Economic Community official approval. Approval certificate made out by an official organ. And performance certificate or calibration made out by an official organ or an officially accredited laboratory.