Center Pivot Irrigation System
When we refer to irrigation, we simply mean providing a regular supply of water to a crop.
A center pivot irrigation system starts with a source of water, generally in the center of a field. The source may be a canal, a well, or any water supply which is consistent. Pipes or hoses which are connected to the water source transport the water through trusses as far as the length of the field. The pipes are held above ground level, above the crop, by the trusses.
The pivot can move slowly around the field because the trusses are attached to wheeled supports.
In order to further illustrate, if you consider a bicycle wheel with a hub and spokes. The spokes are attached to the central hub, as well as the outer rim of the wheel. The spokes move around the hub as the wheel turns.
The growing crop is sprayed or sprinkled by the sprinkler heads which are attached to the trusses, or from hoses which are set at a height just above the level of the crop.
The two key benefits of a center pivot irrigation system are that crop receive a consistent water supply and that wind drift and water evaporation are greatly reduced.
Consistent Water Supply
By watering a crop consistently deeply, it encourages the roots to grow downwards into the soil. This helps to produce a healthy, strong crop. Pivot irrigation does just that, whereby the farmer can determine how often the crop will receive water, and how much water to provide.
The water is given time to penetrate the soil because, typically, a pivot will take approximately three days to make a complete rotation. Further, the soil is given time to dry between each watering, in order for the crop to not remain in water.
Water Loss Minimized
Wind drift and water evaporation may well result in major water loss when using a typical irrigation system. However, a center pivot irrigation system allows for spot-directed irrigation. Because this system is set up with the hoses aligned merely a few inches above the level of the crop, there is almost no water loss due to evaporation or wind drift.
Hydrostatic Drive or Electric Drive
There are a total of five major producers of center pivot irrigation system supplies. Namely:
- Lindsay Corporation
- Raintex Irrigation
- T-L Irrigation
- Valley (Valmont Irrigation)
The only company providing hydrostatic equipment is T-L Irrigation. Hydrostatic allows the pivot to be powered and propelled by water. Otherwise, all other manufacturers offer equipment which is powered by 480 volt electricity.
Electrically powered center pivot irrigation systems have a number of drawbacks compared to hydrostatic irrigation systems. Instead of the motion being continuous, the propelling motors and other equipment rely on sensors to direct the forward movement. This tends to result in equipment wear-and-tear, which drives the maintenance costs higher.
What’s more however, due to the nature of the “stop and start” motion, the application of irrigation water tends to be variable.
Crops Suited to a Center Pivot Irrigation System
Crops suited to this type of irrigation system include corn, sugar beet, wheat, alfalfa, soybean, sunflowers, edible beans, and more.
This type of irrigation system is suited to very large areas of land, where sometimes the pivot alone can be as much as one-quarter mile in length.
The sprinkler heads that are nearest to the central hub are constricted to some extent so that the whole length of the extension arm receives water. Furthermore, the use of sprinkler heads called “big guns”, which are located at the very end of each pivot arm, allow irrigation to reach to the farthest edges of a field.
Generally, pivot irrigation is used on flat fields, but they can also be utilized on land where there is a slight roll.
The center pivot irrigation system has many benefits to offer, and many farmers are finding that it satisfies their own crops’ consistent irrigation needs.