Sprinkler irrigation was initially invented for home lawn care and garden water use. Even today, the rhythmic ‘chk-chk-chk’ sound of an impact sprinkler is iconoclastic of hot summer days, green lawns, and children playfully cooling off in lawn sprinklers.
But while spray irrigation technology was originally about personal use, it is such helpful technology that it was rapidly adopted into agriculture as one of the most common types of irrigation systems. Farmers quickly recognized the advantages of reliable, high-pressure water delivery for their watering systems.
So, what do farmers today need to know when it comes to sprinkler irrigation systems?
Table of Contents
What Is Sprinkler Irrigation?
Sprinkler irrigation is any irrigation that uses a pressurized system to apply water in a method that mimics rainfall to the soil surface.
Water is delivered to a farmer’s fields through a network of pipes or hoses, and the water is usually pressurized using a pumping system. Irrigation sprinkler systems may be temporary, movable or permanent.
In the United States, nearly 4.4 million acres are irrigated via some method of spray, aka sprinkler irrigation, not including center pivot or micro-spray irrigation, according to the 2018 United States Department of Agriculture (USDA) report “Sprinkler Irrigation in the Fields and Open.”
Sprinkler irrigation is widely used because it is versatile, adaptable to almost all crops, and affordable. But it’s not a perfect irrigation system. Spray irrigation is one of the most inefficient watering methods, wasting approximately 30 to 50% of the water applied through run-off and evaporation. Only flood irrigation is a more potentially inefficient method of irrigation crops, whereas systems like drip irrigation and sub-irrigation use much less water to achieve effective application rates.
This is an essential consideration because worldwide, farmers are grappling with increasing drought, higher temperatures, and growing populations sucking up the planet’s finite water resources and resulting in restricted water access for agricultural purposes. According to a recently published study, water scarcity is predicted to become a more significant issue in more than 80% of the world’s croplands by 2050.
As farmers plan for their future, carefully considering the type of irrigation system they employ and exploring ways to maximize the efficiency of the system they install is becoming an increasingly critical component of successful farm management.
The Difference Between Spray and Sprinkler Irrigation
Many farmers wonder what the difference is between spray and sprinkler irrigation systems. The answer is nothing. It is just different terminology for the same irrigation system.
We will use the terms sprinkler and spray irrigation interchangeably for this report.
The History of the Sprinkler
Agricultural sprinkler systems began with the American desire to have a lush, green lawn.
Joseph Lessler of Buffalo, New York, invented the first sprinkler in 1871. Lessler described his invention as a “portable water fountain and sprinkler,” and it was billed as a way to save time on lawn care by eliminating the need to water a yard manually.
This new way of delivering water in a manner replicating rain had apparent implications for farmers. By 1932 the impact sprinkler head, which distributed even more water over a wider area, was invented by a California fruit farmer. In time, other technology in sprinkler systems like oscillating sprinklers, pop-up risers on timers, and agricultural-specific advancements like center pivot systems and low-pressure micro-sprinklers would give farmers many options in spray irrigation systems.
Types of Sprinkler Irrigation Systems
Several different types of spray irrigation systems are commonly employed for farm irrigation methods.
Cable Tow System
A cable-tow system is a traveling gun irrigation system. It comprises a large sprinkler head connected to a flexible hose that runs to the water source. The sprinkler is installed on a wheeled cart and is propelled through the field by a cable that winds itself around a drum mounted on the cart.
Cable tow systems are helpful for many different crops but require a cleared lane to travel down and a stationary object at the end of the field, like a tractor, as an anchor.
Hose-Pull Traveler System
A hose-pull traveler is similar to the cable tow but does not require a cable or a stationary object as an anchor. A hose-pull traveler irrigation system uses a wheeled cart installed with a gun-type sprinkler and a semi-rigid polyethylene hose that winds up on a large reel mounted on a second wheeled cart.
The sprinkler cart is propelled through the field as the hose winds onto the mounted reel.
Solid Set Irrigation
Solid set irrigation systems are made up of evenly-spaced sprinkler heads mounted on risers along a length of pipe. They typically use impact sprinkler heads, although different types of sprinkler heads may be installed depending on the crop requirement. The line is above ground and is movable. These systems are most commonly used on smaller farms or high-value crops such as vegetables. Spacing and spray patterns are easily adjusted by switching out different spray heads or changing the space between risers.
Permanent Set Irrigation
Permanent set irrigation systems are similar to solid set irrigation systems, except for the difference that the pipe (typically PVC plastic) is buried underground. These systems are inexpensive to use once set up and can be automated but are the most expensive to install. They are most commonly used in long-term perennial plantings, such as orchard trees or berries.
Micro-sprinkler systems are a low-pressure type of spray irrigation. However, they are typically classified together with drip irrigation because the system for delivery is the same. Micro-sprinklers are small, low-pressure sprinklers inserted into a small, typical ½-inch diameter mainline tube.
While sprinkler heads can be switched to adjust droplet size and spray, impact sprinklers aren’t utilized in micro-sprinkler systems because the system doesn’t deliver enough water pressure to pressurize an impact sprinkler.
Center Pivot Irrigation
Center pivot irrigation systems are among the most commonly used irrigation systems, especially in the United States. They propel themselves around a central pivot point, creating the circular green fields standard throughout the Midwest.
Center pivot systems are quite large, capable of irrigating 125 to 130 acres. They are comprised of a lateral, stainless steel pipe mounted across mobile truss structures. Sprinkler heads are mounted along the length of the line, either directly from the overhead pipe or hanging down from lateral pipes. Center pivot systems are best used in circular fields as areas outside the circular pattern will not be irrigated.
Linear Move Irrigation
A linear move irrigation system is similar to a center pivot system, but rather than pivoting around a central point, it moves laterally through a field. They work in a square or rectangular-shaped field.
The Pros of a Sprinkler Irrigation
Flexible for Many Crops and Farms
Sprinkler irrigation systems are flexible for many different crops, regions, and soil types. They can be designed to match the dimensions of a field and accommodate hills and uneven terrain, issues that challenge other irrigation systems like furrow irrigation. By swapping out different types of sprinkler heads or nozzles, changing the height of the risers sprinklers are mounted on, or adjusting the water pressure or even pipe size, farmers can change the diameter and impact of how water is applied to crops and the soil surface.
Can Be Used to Apply Fertilizers and Chemicals
Farmers can easily use their sprinkler irrigation system to fertilize or apply chemicals by including a fertigation or chemigation component in their irrigation system.
Delivers a Lot of Water When Needed
Sprinkler irrigation systems are an excellent way to deliver much water when it is most needed uniformly across an area. For this reason, sprinkler irrigation systems are often set up in high-value crops like orchards or salad greens for secondary reasons—like cooling during hot weather or preventing cold weather damage during sudden freezes.
The Cons of Sprinkler Irrigation
Water Use Is Intensive
Water efficiency is low in sprinkler irrigation systems because of evaporation and run-off. Although some types of irrigation systems, like flood irrigation, waste even more water, other types of irrigation like drip irrigation and sub-irrigation may be choices for conserving water use when access to irrigation water is limited.
Expensive and Labor Intensive
Sprinkler irrigation systems can be expensive to install or run, especially compared to flood irrigation, the most inexpensive way to irrigate.
A standard center pivot system, for instance, easily costs around $80,000 though once it is set up, it requires very little labor to deliver water to large acreage. A center-pivot system per acre expenses about $600 per acre to install and run. Solid set irrigation systems are generally installed on smaller plots and more high-value crops. They require more labor to operate, so while their upfront costs are cheaper, they still average more per acre to run-generally about $2,000 per acre. Micro-sprinkler irrigation systems are generally considered even more expensive on a per-acre basis for installation and labor costs.
Can Damage Plants
Spray irrigation can lead to plant damage. Scalding occurs when water droplets on leaves are heated up by sun rays creating a powerful magnifying effect. Sprinkler irrigation can also promote foliar diseases such as blight from the increased humidity and wetness left on the leaf mass.
Components Required In Spray Irrigation System
No matter what type of sprinkler irrigation system a grower chooses, the essential components are all the same and can easily be set up DIY with basic tools and understanding.
A water supply for a sprinkler irrigation system can be groundwater or surface water, such as a pond, river, or irrigation channel. Municipal wastewater is also a potential source for sprinkler irrigation systems though there are strict health and safety restrictions for using wastewater.
Water Delivery System
Generally speaking, a water delivery system for a sprinkler irrigation system requires a motorized pump to create the necessary high-pressure volume for most spray irrigation systems.
Pumping systems are generally either electrified or gas-driven. Pipes, or hoses, are crucial additional components in bringing the water from the source to the field. Pipes may be constructed from PVC pipe or metal, and there are many types of hoses used for moving water to farm fields, including large-scale industrial hose systems.
Sprinkler heads are another prominent part of a sprinkler irrigation system. There are many different types of sprinkler heads that can adjust the volume, spray pattern and even flow rate of water application.
Risers, Timers, and Valves
Risers, timers, and valves are additional parts commonly used in most sprinkler irrigation systems. Valves allow a farmer to adjust the application rate between different system sections, while timers can be used to manage a system autonomously. Risers, of course, affect how far above a crop canopy the water is applied. Pressure regulators may also be used in a low-pressure micro-sprinkler irrigation system to prevent over-pressurizing the system.
Next-Gen Technology and Sprinkler Irrigation
Like every type of irrigation system, new irrigation technology combined with precision farming methodologies has made sprinkler irrigation systems more water and cost-efficient for farmers to employ.
New advancements like low-flow rate emitters and micro-sprinklers plus variable rate irrigation and moisture sensors help farmers to more precisely manage how much and how often they run their automatic sprinkler systems to meet their crop needs.
Farm Management Software and Sprinkler Irrigation
AGRIVI farm management software helps farmers run, monitor, and evaluate the effectiveness of their irrigation system no matter what type of watering system they choose.
AGRIVI lets growers record and track any irrigation activity. For instance, a farmer can record the exact amount of water used, when it was used, its source, and the labor costs for running the system and then use that information to calculate the irrigation ROI for that specific crop based on harvest returns.
Farmers can also use AGRIVI to manage and automate water distribution across their farm fields using our IoT hardware. This helps farmers make efficient decisions, especially when water resources are limited while saving time and labor.